OSCL-LXR linux-6.0.1/​drivers/​gpu/​drm/​drm_atomic_helper.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * Copyright (C) 2014 Red Hat
  * Copyright (C) 2014 Intel Corp.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  *
  * Authors:
  * Rob Clark <robdclark@gmail.com>
  * Daniel Vetter <daniel.vetter@ffwll.ch>
  */
 
 #include <linux/dma-fence.h>
 #include <linux/ktime.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_atomic_uapi.h>
 #include <drm/drm_blend.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_damage_helper.h>
 #include <drm/drm_device.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_print.h>
 #include <drm/drm_self_refresh_helper.h>
 #include <drm/drm_vblank.h>
 #include <drm/drm_writeback.h>
 
 #include "drm_crtc_helper_internal.h"
 #include "drm_crtc_internal.h"
 
 /**
  * DOC: overview
  *
  * This helper library provides implementations of check and commit functions on
  * top of the CRTC modeset helper callbacks and the plane helper callbacks. It
  * also provides convenience implementations for the atomic state handling
  * callbacks for drivers which don't need to subclass the drm core structures to
  * add their own additional internal state.
  *
  * This library also provides default implementations for the check callback in
  * drm_atomic_helper_check() and for the commit callback with
  * drm_atomic_helper_commit(). But the individual stages and callbacks are
  * exposed to allow drivers to mix and match and e.g. use the plane helpers only
  * together with a driver private modeset implementation.
  *
  * This library also provides implementations for all the legacy driver
  * interfaces on top of the atomic interface. See drm_atomic_helper_set_config(),
  * drm_atomic_helper_disable_plane(), and the various functions to implement
  * set_property callbacks. New drivers must not implement these functions
  * themselves but must use the provided helpers.
  *
  * The atomic helper uses the same function table structures as all other
  * modesetting helpers. See the documentation for &struct drm_crtc_helper_funcs,
  * struct &drm_encoder_helper_funcs and &struct drm_connector_helper_funcs. It
  * also shares the &struct drm_plane_helper_funcs function table with the plane
  * helpers.
  */
 static void
 drm_atomic_helper_plane_changed(struct drm_atomic_state *state,
                 struct drm_plane_state *old_plane_state,
                 struct drm_plane_state *plane_state,
                 struct drm_plane *plane)
 {
     struct drm_crtc_state *crtc_state;
 
     if (old_plane_state->crtc) {
         crtc_state = drm_atomic_get_new_crtc_state(state,
                                old_plane_state->crtc);
 
         if (WARN_ON(!crtc_state))
             return;
 
         crtc_state->planes_changed = true;
     }
 
     if (plane_state->crtc) {
         crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc);
 
         if (WARN_ON(!crtc_state))
             return;
 
         crtc_state->planes_changed = true;
     }
 }
 
 static int handle_conflicting_encoders(struct drm_atomic_state *state,
                        bool disable_conflicting_encoders)
 {
     struct drm_connector_state *new_conn_state;
     struct drm_connector *connector;
     struct drm_connector_list_iter conn_iter;
     struct drm_encoder *encoder;
     unsigned int encoder_mask = 0;
     int i, ret = 0;
 
     /*
      * First loop, find all newly assigned encoders from the connectors
      * part of the state. If the same encoder is assigned to multiple
      * connectors bail out.
      */
     for_each_new_connector_in_state(state, connector, new_conn_state, i) {
         const struct drm_connector_helper_funcs *funcs = connector->helper_private;
         struct drm_encoder *new_encoder;
 
         if (!new_conn_state->crtc)
             continue;
 
         if (funcs->atomic_best_encoder)
             new_encoder = funcs->atomic_best_encoder(connector,
                                  state);
         else if (funcs->best_encoder)
             new_encoder = funcs->best_encoder(connector);
         else
             new_encoder = drm_connector_get_single_encoder(connector);
 
         if (new_encoder) {
             if (encoder_mask & drm_encoder_mask(new_encoder)) {
                 drm_dbg_atomic(connector->dev,
                            "[ENCODER:%d:%s] on [CONNECTOR:%d:%s] already assigned\n",
                            new_encoder->base.id, new_encoder->name,
                            connector->base.id, connector->name);
 
                 return -EINVAL;
             }
 
             encoder_mask |= drm_encoder_mask(new_encoder);
         }
     }
 
     if (!encoder_mask)
         return 0;
 
     /*
      * Second loop, iterate over all connectors not part of the state.
      *
      * If a conflicting encoder is found and disable_conflicting_encoders
      * is not set, an error is returned. Userspace can provide a solution
      * through the atomic ioctl.
      *
      * If the flag is set conflicting connectors are removed from the CRTC
      * and the CRTC is disabled if no encoder is left. This preserves
      * compatibility with the legacy set_config behavior.
      */
     drm_connector_list_iter_begin(state->dev, &conn_iter);
     drm_for_each_connector_iter(connector, &conn_iter) {
         struct drm_crtc_state *crtc_state;
 
         if (drm_atomic_get_new_connector_state(state, connector))
             continue;
 
         encoder = connector->state->best_encoder;
         if (!encoder || !(encoder_mask & drm_encoder_mask(encoder)))
             continue;
 
         if (!disable_conflicting_encoders) {
             drm_dbg_atomic(connector->dev,
                        "[ENCODER:%d:%s] in use on [CRTC:%d:%s] by [CONNECTOR:%d:%s]\n",
                        encoder->base.id, encoder->name,
                        connector->state->crtc->base.id,
                        connector->state->crtc->name,
                        connector->base.id, connector->name);
             ret = -EINVAL;
             goto out;
         }
 
         new_conn_state = drm_atomic_get_connector_state(state, connector);
         if (IS_ERR(new_conn_state)) {
             ret = PTR_ERR(new_conn_state);
             goto out;
         }
 
         drm_dbg_atomic(connector->dev,
                    "[ENCODER:%d:%s] in use on [CRTC:%d:%s], disabling [CONNECTOR:%d:%s]\n",
                    encoder->base.id, encoder->name,
                    new_conn_state->crtc->base.id, new_conn_state->crtc->name,
                    connector->base.id, connector->name);
 
         crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
 
         ret = drm_atomic_set_crtc_for_connector(new_conn_state, NULL);
         if (ret)
             goto out;
 
         if (!crtc_state->connector_mask) {
             ret = drm_atomic_set_mode_prop_for_crtc(crtc_state,
                                 NULL);
             if (ret < 0)
                 goto out;
 
             crtc_state->active = false;
         }
     }
 out:
     drm_connector_list_iter_end(&conn_iter);
 
     return ret;
 }
 
 static void
 set_best_encoder(struct drm_atomic_state *state,
          struct drm_connector_state *conn_state,
          struct drm_encoder *encoder)
 {
     struct drm_crtc_state *crtc_state;
     struct drm_crtc *crtc;
 
     if (conn_state->best_encoder) {
         /* Unset the encoder_mask in the old crtc state. */
         crtc = conn_state->connector->state->crtc;
 
         /* A NULL crtc is an error here because we should have
          * duplicated a NULL best_encoder when crtc was NULL.
          * As an exception restoring duplicated atomic state
          * during resume is allowed, so don't warn when
          * best_encoder is equal to encoder we intend to set.
          */
         WARN_ON(!crtc && encoder != conn_state->best_encoder);
         if (crtc) {
             crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
             crtc_state->encoder_mask &=
                 ~drm_encoder_mask(conn_state->best_encoder);
         }
     }
 
     if (encoder) {
         crtc = conn_state->crtc;
         WARN_ON(!crtc);
         if (crtc) {
             crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
             crtc_state->encoder_mask |=
                 drm_encoder_mask(encoder);
         }
     }
 
     conn_state->best_encoder = encoder;
 }
 
 static void
 steal_encoder(struct drm_atomic_state *state,
           struct drm_encoder *encoder)
 {
     struct drm_crtc_state *crtc_state;
     struct drm_connector *connector;
     struct drm_connector_state *old_connector_state, *new_connector_state;
     int i;
 
     for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
         struct drm_crtc *encoder_crtc;
 
         if (new_connector_state->best_encoder != encoder)
             continue;
 
         encoder_crtc = old_connector_state->crtc;
 
         drm_dbg_atomic(encoder->dev,
                    "[ENCODER:%d:%s] in use on [CRTC:%d:%s], stealing it\n",
                    encoder->base.id, encoder->name,
                    encoder_crtc->base.id, encoder_crtc->name);
 
         set_best_encoder(state, new_connector_state, NULL);
 
         crtc_state = drm_atomic_get_new_crtc_state(state, encoder_crtc);
         crtc_state->connectors_changed = true;
 
         return;
     }
 }
 
 static int
 update_connector_routing(struct drm_atomic_state *state,
              struct drm_connector *connector,
              struct drm_connector_state *old_connector_state,
              struct drm_connector_state *new_connector_state)
 {
     const struct drm_connector_helper_funcs *funcs;
     struct drm_encoder *new_encoder;
     struct drm_crtc_state *crtc_state;
 
     drm_dbg_atomic(connector->dev, "Updating routing for [CONNECTOR:%d:%s]\n",
                connector->base.id, connector->name);
 
     if (old_connector_state->crtc != new_connector_state->crtc) {
         if (old_connector_state->crtc) {
             crtc_state = drm_atomic_get_new_crtc_state(state, old_connector_state->crtc);
             crtc_state->connectors_changed = true;
         }
 
         if (new_connector_state->crtc) {
             crtc_state = drm_atomic_get_new_crtc_state(state, new_connector_state->crtc);
             crtc_state->connectors_changed = true;
         }
     }
 
     if (!new_connector_state->crtc) {
         drm_dbg_atomic(connector->dev, "Disabling [CONNECTOR:%d:%s]\n",
                 connector->base.id, connector->name);
 
         set_best_encoder(state, new_connector_state, NULL);
 
         return 0;
     }
 
     crtc_state = drm_atomic_get_new_crtc_state(state,
                            new_connector_state->crtc);
     /*
      * For compatibility with legacy users, we want to make sure that
      * we allow DPMS On->Off modesets on unregistered connectors. Modesets
      * which would result in anything else must be considered invalid, to
      * avoid turning on new displays on dead connectors.
      *
      * Since the connector can be unregistered at any point during an
      * atomic check or commit, this is racy. But that's OK: all we care
      * about is ensuring that userspace can't do anything but shut off the
      * display on a connector that was destroyed after it's been notified,
      * not before.
      *
      * Additionally, we also want to ignore connector registration when
      * we're trying to restore an atomic state during system resume since
      * there's a chance the connector may have been destroyed during the
      * process, but it's better to ignore that then cause
      * drm_atomic_helper_resume() to fail.
      */
     if (!state->duplicated && drm_connector_is_unregistered(connector) &&
         crtc_state->active) {
         drm_dbg_atomic(connector->dev,
                    "[CONNECTOR:%d:%s] is not registered\n",
                    connector->base.id, connector->name);
         return -EINVAL;
     }
 
     funcs = connector->helper_private;
 
     if (funcs->atomic_best_encoder)
         new_encoder = funcs->atomic_best_encoder(connector, state);
     else if (funcs->best_encoder)
         new_encoder = funcs->best_encoder(connector);
     else
         new_encoder = drm_connector_get_single_encoder(connector);
 
     if (!new_encoder) {
         drm_dbg_atomic(connector->dev,
                    "No suitable encoder found for [CONNECTOR:%d:%s]\n",
                    connector->base.id, connector->name);
         return -EINVAL;
     }
 
     if (!drm_encoder_crtc_ok(new_encoder, new_connector_state->crtc)) {
         drm_dbg_atomic(connector->dev,
                    "[ENCODER:%d:%s] incompatible with [CRTC:%d:%s]\n",
                    new_encoder->base.id,
                    new_encoder->name,
                    new_connector_state->crtc->base.id,
                    new_connector_state->crtc->name);
         return -EINVAL;
     }
 
     if (new_encoder == new_connector_state->best_encoder) {
         set_best_encoder(state, new_connector_state, new_encoder);
 
         drm_dbg_atomic(connector->dev,
                    "[CONNECTOR:%d:%s] keeps [ENCODER:%d:%s], now on [CRTC:%d:%s]\n",
                    connector->base.id,
                    connector->name,
                    new_encoder->base.id,
                    new_encoder->name,
                    new_connector_state->crtc->base.id,
                    new_connector_state->crtc->name);
 
         return 0;
     }
 
     steal_encoder(state, new_encoder);
 
     set_best_encoder(state, new_connector_state, new_encoder);
 
     crtc_state->connectors_changed = true;
 
     drm_dbg_atomic(connector->dev,
                "[CONNECTOR:%d:%s] using [ENCODER:%d:%s] on [CRTC:%d:%s]\n",
                connector->base.id,
                connector->name,
                new_encoder->base.id,
                new_encoder->name,
                new_connector_state->crtc->base.id,
                new_connector_state->crtc->name);
 
     return 0;
 }
 
 static int
 mode_fixup(struct drm_atomic_state *state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *new_crtc_state;
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     int i;
     int ret;
 
     for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
         if (!new_crtc_state->mode_changed &&
             !new_crtc_state->connectors_changed)
             continue;
 
         drm_mode_copy(&new_crtc_state->adjusted_mode, &new_crtc_state->mode);
     }
 
     for_each_new_connector_in_state(state, connector, new_conn_state, i) {
         const struct drm_encoder_helper_funcs *funcs;
         struct drm_encoder *encoder;
         struct drm_bridge *bridge;
 
         WARN_ON(!!new_conn_state->best_encoder != !!new_conn_state->crtc);
 
         if (!new_conn_state->crtc || !new_conn_state->best_encoder)
             continue;
 
         new_crtc_state =
             drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
 
         /*
          * Each encoder has at most one connector (since we always steal
          * it away), so we won't call ->mode_fixup twice.
          */
         encoder = new_conn_state->best_encoder;
         funcs = encoder->helper_private;
 
         bridge = drm_bridge_chain_get_first_bridge(encoder);
         ret = drm_atomic_bridge_chain_check(bridge,
                             new_crtc_state,
                             new_conn_state);
         if (ret) {
             drm_dbg_atomic(encoder->dev, "Bridge atomic check failed\n");
             return ret;
         }
 
         if (funcs && funcs->atomic_check) {
             ret = funcs->atomic_check(encoder, new_crtc_state,
                           new_conn_state);
             if (ret) {
                 drm_dbg_atomic(encoder->dev,
                            "[ENCODER:%d:%s] check failed\n",
                            encoder->base.id, encoder->name);
                 return ret;
             }
         } else if (funcs && funcs->mode_fixup) {
             ret = funcs->mode_fixup(encoder, &new_crtc_state->mode,
                         &new_crtc_state->adjusted_mode);
             if (!ret) {
                 drm_dbg_atomic(encoder->dev,
                            "[ENCODER:%d:%s] fixup failed\n",
                            encoder->base.id, encoder->name);
                 return -EINVAL;
             }
         }
     }
 
     for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         if (!new_crtc_state->enable)
             continue;
 
         if (!new_crtc_state->mode_changed &&
             !new_crtc_state->connectors_changed)
             continue;
 
         funcs = crtc->helper_private;
         if (!funcs || !funcs->mode_fixup)
             continue;
 
         ret = funcs->mode_fixup(crtc, &new_crtc_state->mode,
                     &new_crtc_state->adjusted_mode);
         if (!ret) {
             drm_dbg_atomic(crtc->dev, "[CRTC:%d:%s] fixup failed\n",
                        crtc->base.id, crtc->name);
             return -EINVAL;
         }
     }
 
     return 0;
 }
 
 static enum drm_mode_status mode_valid_path(struct drm_connector *connector,
                         struct drm_encoder *encoder,
                         struct drm_crtc *crtc,
                         const struct drm_display_mode *mode)
 {
     struct drm_bridge *bridge;
     enum drm_mode_status ret;
 
     ret = drm_encoder_mode_valid(encoder, mode);
     if (ret != MODE_OK) {
         drm_dbg_atomic(encoder->dev,
                    "[ENCODER:%d:%s] mode_valid() failed\n",
                    encoder->base.id, encoder->name);
         return ret;
     }
 
     bridge = drm_bridge_chain_get_first_bridge(encoder);
     ret = drm_bridge_chain_mode_valid(bridge, &connector->display_info,
                       mode);
     if (ret != MODE_OK) {
         drm_dbg_atomic(encoder->dev, "[BRIDGE] mode_valid() failed\n");
         return ret;
     }
 
     ret = drm_crtc_mode_valid(crtc, mode);
     if (ret != MODE_OK) {
         drm_dbg_atomic(encoder->dev, "[CRTC:%d:%s] mode_valid() failed\n",
                    crtc->base.id, crtc->name);
         return ret;
     }
 
     return ret;
 }
 
 static int
 mode_valid(struct drm_atomic_state *state)
 {
     struct drm_connector_state *conn_state;
     struct drm_connector *connector;
     int i;
 
     for_each_new_connector_in_state(state, connector, conn_state, i) {
         struct drm_encoder *encoder = conn_state->best_encoder;
         struct drm_crtc *crtc = conn_state->crtc;
         struct drm_crtc_state *crtc_state;
         enum drm_mode_status mode_status;
         const struct drm_display_mode *mode;
 
         if (!crtc || !encoder)
             continue;
 
         crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
         if (!crtc_state)
             continue;
         if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
             continue;
 
         mode = &crtc_state->mode;
 
         mode_status = mode_valid_path(connector, encoder, crtc, mode);
         if (mode_status != MODE_OK)
             return -EINVAL;
     }
 
     return 0;
 }
 
 /**
  * drm_atomic_helper_check_modeset - validate state object for modeset changes
  * @dev: DRM device
  * @state: the driver state object
  *
  * Check the state object to see if the requested state is physically possible.
  * This does all the CRTC and connector related computations for an atomic
  * update and adds any additional connectors needed for full modesets. It calls
  * the various per-object callbacks in the follow order:
  *
  * 1. &drm_connector_helper_funcs.atomic_best_encoder for determining the new encoder.
  * 2. &drm_connector_helper_funcs.atomic_check to validate the connector state.
  * 3. If it's determined a modeset is needed then all connectors on the affected
  *    CRTC are added and &drm_connector_helper_funcs.atomic_check is run on them.
  * 4. &drm_encoder_helper_funcs.mode_valid, &drm_bridge_funcs.mode_valid and
  *    &drm_crtc_helper_funcs.mode_valid are called on the affected components.
  * 5. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
  * 6. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
  *    This function is only called when the encoder will be part of a configured CRTC,
  *    it must not be used for implementing connector property validation.
  *    If this function is NULL, &drm_atomic_encoder_helper_funcs.mode_fixup is called
  *    instead.
  * 7. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with CRTC constraints.
  *
  * &drm_crtc_state.mode_changed is set when the input mode is changed.
  * &drm_crtc_state.connectors_changed is set when a connector is added or
  * removed from the CRTC.  &drm_crtc_state.active_changed is set when
  * &drm_crtc_state.active changes, which is used for DPMS.
  * &drm_crtc_state.no_vblank is set from the result of drm_dev_has_vblank().
  * See also: drm_atomic_crtc_needs_modeset()
  *
  * IMPORTANT:
  *
  * Drivers which set &drm_crtc_state.mode_changed (e.g. in their
  * &drm_plane_helper_funcs.atomic_check hooks if a plane update can't be done
  * without a full modeset) _must_ call this function after that change. It is
  * permitted to call this function multiple times for the same update, e.g.
  * when the &drm_crtc_helper_funcs.atomic_check functions depend upon the
  * adjusted dotclock for fifo space allocation and watermark computation.
  *
  * RETURNS:
  * Zero for success or -errno
  */
 int
 drm_atomic_helper_check_modeset(struct drm_device *dev,
                 struct drm_atomic_state *state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     struct drm_connector *connector;
     struct drm_connector_state *old_connector_state, *new_connector_state;
     int i, ret;
     unsigned int connectors_mask = 0;
 
     for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
         bool has_connectors =
             !!new_crtc_state->connector_mask;
 
         WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
 
         if (!drm_mode_equal(&old_crtc_state->mode, &new_crtc_state->mode)) {
             drm_dbg_atomic(dev, "[CRTC:%d:%s] mode changed\n",
                        crtc->base.id, crtc->name);
             new_crtc_state->mode_changed = true;
         }
 
         if (old_crtc_state->enable != new_crtc_state->enable) {
             drm_dbg_atomic(dev, "[CRTC:%d:%s] enable changed\n",
                        crtc->base.id, crtc->name);
 
             /*
              * For clarity this assignment is done here, but
              * enable == 0 is only true when there are no
              * connectors and a NULL mode.
              *
              * The other way around is true as well. enable != 0
              * implies that connectors are attached and a mode is set.
              */
             new_crtc_state->mode_changed = true;
             new_crtc_state->connectors_changed = true;
         }
 
         if (old_crtc_state->active != new_crtc_state->active) {
             drm_dbg_atomic(dev, "[CRTC:%d:%s] active changed\n",
                        crtc->base.id, crtc->name);
             new_crtc_state->active_changed = true;
         }
 
         if (new_crtc_state->enable != has_connectors) {
             drm_dbg_atomic(dev, "[CRTC:%d:%s] enabled/connectors mismatch\n",
                        crtc->base.id, crtc->name);
 
             return -EINVAL;
         }
 
         if (drm_dev_has_vblank(dev))
             new_crtc_state->no_vblank = false;
         else
             new_crtc_state->no_vblank = true;
     }
 
     ret = handle_conflicting_encoders(state, false);
     if (ret)
         return ret;
 
     for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
         const struct drm_connector_helper_funcs *funcs = connector->helper_private;
 
         WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
 
         /*
          * This only sets crtc->connectors_changed for routing changes,
          * drivers must set crtc->connectors_changed themselves when
          * connector properties need to be updated.
          */
         ret = update_connector_routing(state, connector,
                            old_connector_state,
                            new_connector_state);
         if (ret)
             return ret;
         if (old_connector_state->crtc) {
             new_crtc_state = drm_atomic_get_new_crtc_state(state,
                                        old_connector_state->crtc);
             if (old_connector_state->link_status !=
                 new_connector_state->link_status)
                 new_crtc_state->connectors_changed = true;
 
             if (old_connector_state->max_requested_bpc !=
                 new_connector_state->max_requested_bpc)
                 new_crtc_state->connectors_changed = true;
         }
 
         if (funcs->atomic_check)
             ret = funcs->atomic_check(connector, state);
         if (ret)
             return ret;
 
         connectors_mask |= BIT(i);
     }
 
     /*
      * After all the routing has been prepared we need to add in any
      * connector which is itself unchanged, but whose CRTC changes its
      * configuration. This must be done before calling mode_fixup in case a
      * crtc only changed its mode but has the same set of connectors.
      */
     for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
         if (!drm_atomic_crtc_needs_modeset(new_crtc_state))
             continue;
 
         drm_dbg_atomic(dev,
                    "[CRTC:%d:%s] needs all connectors, enable: %c, active: %c\n",
                    crtc->base.id, crtc->name,
                    new_crtc_state->enable ? 'y' : 'n',
                    new_crtc_state->active ? 'y' : 'n');
 
         ret = drm_atomic_add_affected_connectors(state, crtc);
         if (ret != 0)
             return ret;
 
         ret = drm_atomic_add_affected_planes(state, crtc);
         if (ret != 0)
             return ret;
     }
 
     /*
      * Iterate over all connectors again, to make sure atomic_check()
      * has been called on them when a modeset is forced.
      */
     for_each_oldnew_connector_in_state(state, connector, old_connector_state, new_connector_state, i) {
         const struct drm_connector_helper_funcs *funcs = connector->helper_private;
 
         if (connectors_mask & BIT(i))
             continue;
 
         if (funcs->atomic_check)
             ret = funcs->atomic_check(connector, state);
         if (ret)
             return ret;
     }
 
     /*
      * Iterate over all connectors again, and add all affected bridges to
      * the state.
      */
     for_each_oldnew_connector_in_state(state, connector,
                        old_connector_state,
                        new_connector_state, i) {
         struct drm_encoder *encoder;
 
         encoder = old_connector_state->best_encoder;
         ret = drm_atomic_add_encoder_bridges(state, encoder);
         if (ret)
             return ret;
 
         encoder = new_connector_state->best_encoder;
         ret = drm_atomic_add_encoder_bridges(state, encoder);
         if (ret)
             return ret;
     }
 
     ret = mode_valid(state);
     if (ret)
         return ret;
 
     return mode_fixup(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
 
 /**
  * drm_atomic_helper_check_plane_state() - Check plane state for validity
  * @plane_state: plane state to check
  * @crtc_state: CRTC state to check
  * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
  * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
  * @can_position: is it legal to position the plane such that it
  *                doesn't cover the entire CRTC?  This will generally
  *                only be false for primary planes.
  * @can_update_disabled: can the plane be updated while the CRTC
  *                       is disabled?
  *
  * Checks that a desired plane update is valid, and updates various
  * bits of derived state (clipped coordinates etc.). Drivers that provide
  * their own plane handling rather than helper-provided implementations may
  * still wish to call this function to avoid duplication of error checking
  * code.
  *
  * RETURNS:
  * Zero if update appears valid, error code on failure
  */
 int drm_atomic_helper_check_plane_state(struct drm_plane_state *plane_state,
                     const struct drm_crtc_state *crtc_state,
                     int min_scale,
                     int max_scale,
                     bool can_position,
                     bool can_update_disabled)
 {
     struct drm_framebuffer *fb = plane_state->fb;
     struct drm_rect *src = &plane_state->src;
     struct drm_rect *dst = &plane_state->dst;
     unsigned int rotation = plane_state->rotation;
     struct drm_rect clip = {};
     int hscale, vscale;
 
     WARN_ON(plane_state->crtc && plane_state->crtc != crtc_state->crtc);
 
     *src = drm_plane_state_src(plane_state);
     *dst = drm_plane_state_dest(plane_state);
 
     if (!fb) {
         plane_state->visible = false;
         return 0;
     }
 
     /* crtc should only be NULL when disabling (i.e., !fb) */
     if (WARN_ON(!plane_state->crtc)) {
         plane_state->visible = false;
         return 0;
     }
 
     if (!crtc_state->enable && !can_update_disabled) {
         drm_dbg_kms(plane_state->plane->dev,
                 "Cannot update plane of a disabled CRTC.\n");
         return -EINVAL;
     }
 
     drm_rect_rotate(src, fb->width << 16, fb->height << 16, rotation);
 
     /* Check scaling */
     hscale = drm_rect_calc_hscale(src, dst, min_scale, max_scale);
     vscale = drm_rect_calc_vscale(src, dst, min_scale, max_scale);
     if (hscale < 0 || vscale < 0) {
         drm_dbg_kms(plane_state->plane->dev,
                 "Invalid scaling of plane\n");
         drm_rect_debug_print("src: ", &plane_state->src, true);
         drm_rect_debug_print("dst: ", &plane_state->dst, false);
         return -ERANGE;
     }
 
     if (crtc_state->enable)
         drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2);
 
     plane_state->visible = drm_rect_clip_scaled(src, dst, &clip);
 
     drm_rect_rotate_inv(src, fb->width << 16, fb->height << 16, rotation);
 
     if (!plane_state->visible)
         /*
          * Plane isn't visible; some drivers can handle this
          * so we just return success here.  Drivers that can't
          * (including those that use the primary plane helper's
          * update function) will return an error from their
          * update_plane handler.
          */
         return 0;
 
     if (!can_position && !drm_rect_equals(dst, &clip)) {
         drm_dbg_kms(plane_state->plane->dev,
                 "Plane must cover entire CRTC\n");
         drm_rect_debug_print("dst: ", dst, false);
         drm_rect_debug_print("clip: ", &clip, false);
         return -EINVAL;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_plane_state);
 
 /**
  * drm_atomic_helper_check_crtc_state() - Check CRTC state for validity
  * @crtc_state: CRTC state to check
  * @can_disable_primary_planes: can the CRTC be enabled without a primary plane?
  *
  * Checks that a desired CRTC update is valid. Drivers that provide
  * their own CRTC handling rather than helper-provided implementations may
  * still wish to call this function to avoid duplication of error checking
  * code.
  *
  * Note that @can_disable_primary_planes only tests if the CRTC can be
  * enabled without a primary plane. To test if a primary plane can be updated
  * without a CRTC, use drm_atomic_helper_check_plane_state() in the plane's
  * atomic check.
  *
  * RETURNS:
  * Zero if update appears valid, error code on failure
  */
 int drm_atomic_helper_check_crtc_state(struct drm_crtc_state *crtc_state,
                        bool can_disable_primary_planes)
 {
     struct drm_device *dev = crtc_state->crtc->dev;
     struct drm_atomic_state *state = crtc_state->state;
 
     if (!crtc_state->enable)
         return 0;
 
     /* needs at least one primary plane to be enabled */
     if (!can_disable_primary_planes) {
         bool has_primary_plane = false;
         struct drm_plane *plane;
 
         drm_for_each_plane_mask(plane, dev, crtc_state->plane_mask) {
             struct drm_plane_state *plane_state;
 
             if (plane->type != DRM_PLANE_TYPE_PRIMARY)
                 continue;
             plane_state = drm_atomic_get_plane_state(state, plane);
             if (IS_ERR(plane_state))
                 return PTR_ERR(plane_state);
             if (plane_state->fb && plane_state->crtc) {
                 has_primary_plane = true;
                 break;
             }
         }
         if (!has_primary_plane) {
             drm_dbg_kms(dev, "Cannot enable CRTC without a primary plane.\n");
             return -EINVAL;
         }
     }
 
     return 0;
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_crtc_state);
 
 /**
  * drm_atomic_helper_check_planes - validate state object for planes changes
  * @dev: DRM device
  * @state: the driver state object
  *
  * Check the state object to see if the requested state is physically possible.
  * This does all the plane update related checks using by calling into the
  * &drm_crtc_helper_funcs.atomic_check and &drm_plane_helper_funcs.atomic_check
  * hooks provided by the driver.
  *
  * It also sets &drm_crtc_state.planes_changed to indicate that a CRTC has
  * updated planes.
  *
  * RETURNS:
  * Zero for success or -errno
  */
 int
 drm_atomic_helper_check_planes(struct drm_device *dev,
                    struct drm_atomic_state *state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *new_crtc_state;
     struct drm_plane *plane;
     struct drm_plane_state *new_plane_state, *old_plane_state;
     int i, ret = 0;
 
     for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
         const struct drm_plane_helper_funcs *funcs;
 
         WARN_ON(!drm_modeset_is_locked(&plane->mutex));
 
         funcs = plane->helper_private;
 
         drm_atomic_helper_plane_changed(state, old_plane_state, new_plane_state, plane);
 
         drm_atomic_helper_check_plane_damage(state, new_plane_state);
 
         if (!funcs || !funcs->atomic_check)
             continue;
 
         ret = funcs->atomic_check(plane, state);
         if (ret) {
             drm_dbg_atomic(plane->dev,
                        "[PLANE:%d:%s] atomic driver check failed\n",
                        plane->base.id, plane->name);
             return ret;
         }
     }
 
     for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         funcs = crtc->helper_private;
 
         if (!funcs || !funcs->atomic_check)
             continue;
 
         ret = funcs->atomic_check(crtc, state);
         if (ret) {
             drm_dbg_atomic(crtc->dev,
                        "[CRTC:%d:%s] atomic driver check failed\n",
                        crtc->base.id, crtc->name);
             return ret;
         }
     }
 
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_planes);
 
 /**
  * drm_atomic_helper_check - validate state object
  * @dev: DRM device
  * @state: the driver state object
  *
  * Check the state object to see if the requested state is physically possible.
  * Only CRTCs and planes have check callbacks, so for any additional (global)
  * checking that a driver needs it can simply wrap that around this function.
  * Drivers without such needs can directly use this as their
  * &drm_mode_config_funcs.atomic_check callback.
  *
  * This just wraps the two parts of the state checking for planes and modeset
  * state in the default order: First it calls drm_atomic_helper_check_modeset()
  * and then drm_atomic_helper_check_planes(). The assumption is that the
  * @drm_plane_helper_funcs.atomic_check and @drm_crtc_helper_funcs.atomic_check
  * functions depend upon an updated adjusted_mode.clock to e.g. properly compute
  * watermarks.
  *
  * Note that zpos normalization will add all enable planes to the state which
  * might not desired for some drivers.
  * For example enable/disable of a cursor plane which have fixed zpos value
  * would trigger all other enabled planes to be forced to the state change.
  *
  * RETURNS:
  * Zero for success or -errno
  */
 int drm_atomic_helper_check(struct drm_device *dev,
                 struct drm_atomic_state *state)
 {
     int ret;
 
     ret = drm_atomic_helper_check_modeset(dev, state);
     if (ret)
         return ret;
 
     if (dev->mode_config.normalize_zpos) {
         ret = drm_atomic_normalize_zpos(dev, state);
         if (ret)
             return ret;
     }
 
     ret = drm_atomic_helper_check_planes(dev, state);
     if (ret)
         return ret;
 
     if (state->legacy_cursor_update)
         state->async_update = !drm_atomic_helper_async_check(dev, state);
 
     drm_self_refresh_helper_alter_state(state);
 
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_check);
 
 static bool
 crtc_needs_disable(struct drm_crtc_state *old_state,
            struct drm_crtc_state *new_state)
 {
     /*
      * No new_state means the CRTC is off, so the only criteria is whether
      * it's currently active or in self refresh mode.
      */
     if (!new_state)
         return drm_atomic_crtc_effectively_active(old_state);
 
     /*
      * We need to disable bridge(s) and CRTC if we're transitioning out of
      * self-refresh and changing CRTCs at the same time, because the
      * bridge tracks self-refresh status via CRTC state.
      */
     if (old_state->self_refresh_active &&
         old_state->crtc != new_state->crtc)
         return true;
 
     /*
      * We also need to run through the crtc_funcs->disable() function if
      * the CRTC is currently on, if it's transitioning to self refresh
      * mode, or if it's in self refresh mode and needs to be fully
      * disabled.
      */
     return old_state->active ||
            (old_state->self_refresh_active && !new_state->active) ||
            new_state->self_refresh_active;
 }
 
 static void
 disable_outputs(struct drm_device *dev, struct drm_atomic_state *old_state)
 {
     struct drm_connector *connector;
     struct drm_connector_state *old_conn_state, *new_conn_state;
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     int i;
 
     for_each_oldnew_connector_in_state(old_state, connector, old_conn_state, new_conn_state, i) {
         const struct drm_encoder_helper_funcs *funcs;
         struct drm_encoder *encoder;
         struct drm_bridge *bridge;
 
         /*
          * Shut down everything that's in the changeset and currently
          * still on. So need to check the old, saved state.
          */
         if (!old_conn_state->crtc)
             continue;
 
         old_crtc_state = drm_atomic_get_old_crtc_state(old_state, old_conn_state->crtc);
 
         if (new_conn_state->crtc)
             new_crtc_state = drm_atomic_get_new_crtc_state(
                         old_state,
                         new_conn_state->crtc);
         else
             new_crtc_state = NULL;
 
         if (!crtc_needs_disable(old_crtc_state, new_crtc_state) ||
             !drm_atomic_crtc_needs_modeset(old_conn_state->crtc->state))
             continue;
 
         encoder = old_conn_state->best_encoder;
 
         /* We shouldn't get this far if we didn't previously have
          * an encoder.. but WARN_ON() rather than explode.
          */
         if (WARN_ON(!encoder))
             continue;
 
         funcs = encoder->helper_private;
 
         drm_dbg_atomic(dev, "disabling [ENCODER:%d:%s]\n",
                    encoder->base.id, encoder->name);
 
         /*
          * Each encoder has at most one connector (since we always steal
          * it away), so we won't call disable hooks twice.
          */
         bridge = drm_bridge_chain_get_first_bridge(encoder);
         drm_atomic_bridge_chain_disable(bridge, old_state);
 
         /* Right function depends upon target state. */
         if (funcs) {
             if (funcs->atomic_disable)
                 funcs->atomic_disable(encoder, old_state);
             else if (new_conn_state->crtc && funcs->prepare)
                 funcs->prepare(encoder);
             else if (funcs->disable)
                 funcs->disable(encoder);
             else if (funcs->dpms)
                 funcs->dpms(encoder, DRM_MODE_DPMS_OFF);
         }
 
         drm_atomic_bridge_chain_post_disable(bridge, old_state);
     }
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
         int ret;
 
         /* Shut down everything that needs a full modeset. */
         if (!drm_atomic_crtc_needs_modeset(new_crtc_state))
             continue;
 
         if (!crtc_needs_disable(old_crtc_state, new_crtc_state))
             continue;
 
         funcs = crtc->helper_private;
 
         drm_dbg_atomic(dev, "disabling [CRTC:%d:%s]\n",
                    crtc->base.id, crtc->name);
 
 
         /* Right function depends upon target state. */
         if (new_crtc_state->enable && funcs->prepare)
             funcs->prepare(crtc);
         else if (funcs->atomic_disable)
             funcs->atomic_disable(crtc, old_state);
         else if (funcs->disable)
             funcs->disable(crtc);
         else if (funcs->dpms)
             funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
 
         if (!drm_dev_has_vblank(dev))
             continue;
 
         ret = drm_crtc_vblank_get(crtc);
         WARN_ONCE(ret != -EINVAL, "driver forgot to call drm_crtc_vblank_off()\n");
         if (ret == 0)
             drm_crtc_vblank_put(crtc);
     }
 }
 
 /**
  * drm_atomic_helper_update_legacy_modeset_state - update legacy modeset state
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * This function updates all the various legacy modeset state pointers in
  * connectors, encoders and CRTCs.
  *
  * Drivers can use this for building their own atomic commit if they don't have
  * a pure helper-based modeset implementation.
  *
  * Since these updates are not synchronized with lockings, only code paths
  * called from &drm_mode_config_helper_funcs.atomic_commit_tail can look at the
  * legacy state filled out by this helper. Defacto this means this helper and
  * the legacy state pointers are only really useful for transitioning an
  * existing driver to the atomic world.
  */
 void
 drm_atomic_helper_update_legacy_modeset_state(struct drm_device *dev,
                           struct drm_atomic_state *old_state)
 {
     struct drm_connector *connector;
     struct drm_connector_state *old_conn_state, *new_conn_state;
     struct drm_crtc *crtc;
     struct drm_crtc_state *new_crtc_state;
     int i;
 
     /* clear out existing links and update dpms */
     for_each_oldnew_connector_in_state(old_state, connector, old_conn_state, new_conn_state, i) {
         if (connector->encoder) {
             WARN_ON(!connector->encoder->crtc);
 
             connector->encoder->crtc = NULL;
             connector->encoder = NULL;
         }
 
         crtc = new_conn_state->crtc;
         if ((!crtc && old_conn_state->crtc) ||
             (crtc && drm_atomic_crtc_needs_modeset(crtc->state))) {
             int mode = DRM_MODE_DPMS_OFF;
 
             if (crtc && crtc->state->active)
                 mode = DRM_MODE_DPMS_ON;
 
             connector->dpms = mode;
         }
     }
 
     /* set new links */
     for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
         if (!new_conn_state->crtc)
             continue;
 
         if (WARN_ON(!new_conn_state->best_encoder))
             continue;
 
         connector->encoder = new_conn_state->best_encoder;
         connector->encoder->crtc = new_conn_state->crtc;
     }
 
     /* set legacy state in the crtc structure */
     for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) {
         struct drm_plane *primary = crtc->primary;
         struct drm_plane_state *new_plane_state;
 
         crtc->mode = new_crtc_state->mode;
         crtc->enabled = new_crtc_state->enable;
 
         new_plane_state =
             drm_atomic_get_new_plane_state(old_state, primary);
 
         if (new_plane_state && new_plane_state->crtc == crtc) {
             crtc->x = new_plane_state->src_x >> 16;
             crtc->y = new_plane_state->src_y >> 16;
         }
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_update_legacy_modeset_state);
 
 /**
  * drm_atomic_helper_calc_timestamping_constants - update vblank timestamping constants
  * @state: atomic state object
  *
  * Updates the timestamping constants used for precise vblank timestamps
  * by calling drm_calc_timestamping_constants() for all enabled crtcs in @state.
  */
 void drm_atomic_helper_calc_timestamping_constants(struct drm_atomic_state *state)
 {
     struct drm_crtc_state *new_crtc_state;
     struct drm_crtc *crtc;
     int i;
 
     for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
         if (new_crtc_state->enable)
             drm_calc_timestamping_constants(crtc,
                             &new_crtc_state->adjusted_mode);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_calc_timestamping_constants);
 
 static void
 crtc_set_mode(struct drm_device *dev, struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *new_crtc_state;
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     int i;
 
     for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         if (!new_crtc_state->mode_changed)
             continue;
 
         funcs = crtc->helper_private;
 
         if (new_crtc_state->enable && funcs->mode_set_nofb) {
             drm_dbg_atomic(dev, "modeset on [CRTC:%d:%s]\n",
                        crtc->base.id, crtc->name);
 
             funcs->mode_set_nofb(crtc);
         }
     }
 
     for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
         const struct drm_encoder_helper_funcs *funcs;
         struct drm_encoder *encoder;
         struct drm_display_mode *mode, *adjusted_mode;
         struct drm_bridge *bridge;
 
         if (!new_conn_state->best_encoder)
             continue;
 
         encoder = new_conn_state->best_encoder;
         funcs = encoder->helper_private;
         new_crtc_state = new_conn_state->crtc->state;
         mode = &new_crtc_state->mode;
         adjusted_mode = &new_crtc_state->adjusted_mode;
 
         if (!new_crtc_state->mode_changed)
             continue;
 
         drm_dbg_atomic(dev, "modeset on [ENCODER:%d:%s]\n",
                    encoder->base.id, encoder->name);
 
         /*
          * Each encoder has at most one connector (since we always steal
          * it away), so we won't call mode_set hooks twice.
          */
         if (funcs && funcs->atomic_mode_set) {
             funcs->atomic_mode_set(encoder, new_crtc_state,
                            new_conn_state);
         } else if (funcs && funcs->mode_set) {
             funcs->mode_set(encoder, mode, adjusted_mode);
         }
 
         bridge = drm_bridge_chain_get_first_bridge(encoder);
         drm_bridge_chain_mode_set(bridge, mode, adjusted_mode);
     }
 }
 
 /**
  * drm_atomic_helper_commit_modeset_disables - modeset commit to disable outputs
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * This function shuts down all the outputs that need to be shut down and
  * prepares them (if required) with the new mode.
  *
  * For compatibility with legacy CRTC helpers this should be called before
  * drm_atomic_helper_commit_planes(), which is what the default commit function
  * does. But drivers with different needs can group the modeset commits together
  * and do the plane commits at the end. This is useful for drivers doing runtime
  * PM since planes updates then only happen when the CRTC is actually enabled.
  */
 void drm_atomic_helper_commit_modeset_disables(struct drm_device *dev,
                            struct drm_atomic_state *old_state)
 {
     disable_outputs(dev, old_state);
 
     drm_atomic_helper_update_legacy_modeset_state(dev, old_state);
     drm_atomic_helper_calc_timestamping_constants(old_state);
 
     crtc_set_mode(dev, old_state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_disables);
 
 static void drm_atomic_helper_commit_writebacks(struct drm_device *dev,
                         struct drm_atomic_state *old_state)
 {
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     int i;
 
     for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
         const struct drm_connector_helper_funcs *funcs;
 
         funcs = connector->helper_private;
         if (!funcs->atomic_commit)
             continue;
 
         if (new_conn_state->writeback_job && new_conn_state->writeback_job->fb) {
             WARN_ON(connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK);
             funcs->atomic_commit(connector, old_state);
         }
     }
 }
 
 /**
  * drm_atomic_helper_commit_modeset_enables - modeset commit to enable outputs
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * This function enables all the outputs with the new configuration which had to
  * be turned off for the update.
  *
  * For compatibility with legacy CRTC helpers this should be called after
  * drm_atomic_helper_commit_planes(), which is what the default commit function
  * does. But drivers with different needs can group the modeset commits together
  * and do the plane commits at the end. This is useful for drivers doing runtime
  * PM since planes updates then only happen when the CRTC is actually enabled.
  */
 void drm_atomic_helper_commit_modeset_enables(struct drm_device *dev,
                           struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state;
     struct drm_crtc_state *new_crtc_state;
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     int i;
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         /* Need to filter out CRTCs where only planes change. */
         if (!drm_atomic_crtc_needs_modeset(new_crtc_state))
             continue;
 
         if (!new_crtc_state->active)
             continue;
 
         funcs = crtc->helper_private;
 
         if (new_crtc_state->enable) {
             drm_dbg_atomic(dev, "enabling [CRTC:%d:%s]\n",
                        crtc->base.id, crtc->name);
             if (funcs->atomic_enable)
                 funcs->atomic_enable(crtc, old_state);
             else if (funcs->commit)
                 funcs->commit(crtc);
         }
     }
 
     for_each_new_connector_in_state(old_state, connector, new_conn_state, i) {
         const struct drm_encoder_helper_funcs *funcs;
         struct drm_encoder *encoder;
         struct drm_bridge *bridge;
 
         if (!new_conn_state->best_encoder)
             continue;
 
         if (!new_conn_state->crtc->state->active ||
             !drm_atomic_crtc_needs_modeset(new_conn_state->crtc->state))
             continue;
 
         encoder = new_conn_state->best_encoder;
         funcs = encoder->helper_private;
 
         drm_dbg_atomic(dev, "enabling [ENCODER:%d:%s]\n",
                    encoder->base.id, encoder->name);
 
         /*
          * Each encoder has at most one connector (since we always steal
          * it away), so we won't call enable hooks twice.
          */
         bridge = drm_bridge_chain_get_first_bridge(encoder);
         drm_atomic_bridge_chain_pre_enable(bridge, old_state);
 
         if (funcs) {
             if (funcs->atomic_enable)
                 funcs->atomic_enable(encoder, old_state);
             else if (funcs->enable)
                 funcs->enable(encoder);
             else if (funcs->commit)
                 funcs->commit(encoder);
         }
 
         drm_atomic_bridge_chain_enable(bridge, old_state);
     }
 
     drm_atomic_helper_commit_writebacks(dev, old_state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_modeset_enables);
 
 /**
  * drm_atomic_helper_wait_for_fences - wait for fences stashed in plane state
  * @dev: DRM device
  * @state: atomic state object with old state structures
  * @pre_swap: If true, do an interruptible wait, and @state is the new state.
  *  Otherwise @state is the old state.
  *
  * For implicit sync, driver should fish the exclusive fence out from the
  * incoming fb's and stash it in the drm_plane_state.  This is called after
  * drm_atomic_helper_swap_state() so it uses the current plane state (and
  * just uses the atomic state to find the changed planes)
  *
  * Note that @pre_swap is needed since the point where we block for fences moves
  * around depending upon whether an atomic commit is blocking or
  * non-blocking. For non-blocking commit all waiting needs to happen after
  * drm_atomic_helper_swap_state() is called, but for blocking commits we want
  * to wait **before** we do anything that can't be easily rolled back. That is
  * before we call drm_atomic_helper_swap_state().
  *
  * Returns zero if success or < 0 if dma_fence_wait() fails.
  */
 int drm_atomic_helper_wait_for_fences(struct drm_device *dev,
                       struct drm_atomic_state *state,
                       bool pre_swap)
 {
     struct drm_plane *plane;
     struct drm_plane_state *new_plane_state;
     int i, ret;
 
     for_each_new_plane_in_state(state, plane, new_plane_state, i) {
         if (!new_plane_state->fence)
             continue;
 
         WARN_ON(!new_plane_state->fb);
 
         /*
          * If waiting for fences pre-swap (ie: nonblock), userspace can
          * still interrupt the operation. Instead of blocking until the
          * timer expires, make the wait interruptible.
          */
         ret = dma_fence_wait(new_plane_state->fence, pre_swap);
         if (ret)
             return ret;
 
         dma_fence_put(new_plane_state->fence);
         new_plane_state->fence = NULL;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(drm_atomic_helper_wait_for_fences);
 
 /**
  * drm_atomic_helper_wait_for_vblanks - wait for vblank on CRTCs
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * Helper to, after atomic commit, wait for vblanks on all affected
  * CRTCs (ie. before cleaning up old framebuffers using
  * drm_atomic_helper_cleanup_planes()). It will only wait on CRTCs where the
  * framebuffers have actually changed to optimize for the legacy cursor and
  * plane update use-case.
  *
  * Drivers using the nonblocking commit tracking support initialized by calling
  * drm_atomic_helper_setup_commit() should look at
  * drm_atomic_helper_wait_for_flip_done() as an alternative.
  */
 void
 drm_atomic_helper_wait_for_vblanks(struct drm_device *dev,
         struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     int i, ret;
     unsigned int crtc_mask = 0;
 
      /*
       * Legacy cursor ioctls are completely unsynced, and userspace
       * relies on that (by doing tons of cursor updates).
       */
     if (old_state->legacy_cursor_update)
         return;
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         if (!new_crtc_state->active)
             continue;
 
         ret = drm_crtc_vblank_get(crtc);
         if (ret != 0)
             continue;
 
         crtc_mask |= drm_crtc_mask(crtc);
         old_state->crtcs[i].last_vblank_count = drm_crtc_vblank_count(crtc);
     }
 
     for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
         if (!(crtc_mask & drm_crtc_mask(crtc)))
             continue;
 
         ret = wait_event_timeout(dev->vblank[i].queue,
                 old_state->crtcs[i].last_vblank_count !=
                     drm_crtc_vblank_count(crtc),
                 msecs_to_jiffies(100));
 
         WARN(!ret, "[CRTC:%d:%s] vblank wait timed out\n",
              crtc->base.id, crtc->name);
 
         drm_crtc_vblank_put(crtc);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_wait_for_vblanks);
 
 /**
  * drm_atomic_helper_wait_for_flip_done - wait for all page flips to be done
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * Helper to, after atomic commit, wait for page flips on all affected
  * crtcs (ie. before cleaning up old framebuffers using
  * drm_atomic_helper_cleanup_planes()). Compared to
  * drm_atomic_helper_wait_for_vblanks() this waits for the completion on all
  * CRTCs, assuming that cursors-only updates are signalling their completion
  * immediately (or using a different path).
  *
  * This requires that drivers use the nonblocking commit tracking support
  * initialized using drm_atomic_helper_setup_commit().
  */
 void drm_atomic_helper_wait_for_flip_done(struct drm_device *dev,
                       struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     int i;
 
     for (i = 0; i < dev->mode_config.num_crtc; i++) {
         struct drm_crtc_commit *commit = old_state->crtcs[i].commit;
         int ret;
 
         crtc = old_state->crtcs[i].ptr;
 
         if (!crtc || !commit)
             continue;
 
         ret = wait_for_completion_timeout(&commit->flip_done, 10 * HZ);
         if (ret == 0)
             drm_err(dev, "[CRTC:%d:%s] flip_done timed out\n",
                 crtc->base.id, crtc->name);
     }
 
     if (old_state->fake_commit)
         complete_all(&old_state->fake_commit->flip_done);
 }
 EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done);
 
 /**
  * drm_atomic_helper_commit_tail - commit atomic update to hardware
  * @old_state: atomic state object with old state structures
  *
  * This is the default implementation for the
  * &drm_mode_config_helper_funcs.atomic_commit_tail hook, for drivers
  * that do not support runtime_pm or do not need the CRTC to be
  * enabled to perform a commit. Otherwise, see
  * drm_atomic_helper_commit_tail_rpm().
  *
  * Note that the default ordering of how the various stages are called is to
  * match the legacy modeset helper library closest.
  */
 void drm_atomic_helper_commit_tail(struct drm_atomic_state *old_state)
 {
     struct drm_device *dev = old_state->dev;
 
     drm_atomic_helper_commit_modeset_disables(dev, old_state);
 
     drm_atomic_helper_commit_planes(dev, old_state, 0);
 
     drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
     drm_atomic_helper_fake_vblank(old_state);
 
     drm_atomic_helper_commit_hw_done(old_state);
 
     drm_atomic_helper_wait_for_vblanks(dev, old_state);
 
     drm_atomic_helper_cleanup_planes(dev, old_state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_tail);
 
 /**
  * drm_atomic_helper_commit_tail_rpm - commit atomic update to hardware
  * @old_state: new modeset state to be committed
  *
  * This is an alternative implementation for the
  * &drm_mode_config_helper_funcs.atomic_commit_tail hook, for drivers
  * that support runtime_pm or need the CRTC to be enabled to perform a
  * commit. Otherwise, one should use the default implementation
  * drm_atomic_helper_commit_tail().
  */
 void drm_atomic_helper_commit_tail_rpm(struct drm_atomic_state *old_state)
 {
     struct drm_device *dev = old_state->dev;
 
     drm_atomic_helper_commit_modeset_disables(dev, old_state);
 
     drm_atomic_helper_commit_modeset_enables(dev, old_state);
 
     drm_atomic_helper_commit_planes(dev, old_state,
                     DRM_PLANE_COMMIT_ACTIVE_ONLY);
 
     drm_atomic_helper_fake_vblank(old_state);
 
     drm_atomic_helper_commit_hw_done(old_state);
 
     drm_atomic_helper_wait_for_vblanks(dev, old_state);
 
     drm_atomic_helper_cleanup_planes(dev, old_state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_tail_rpm);
 
 static void commit_tail(struct drm_atomic_state *old_state)
 {
     struct drm_device *dev = old_state->dev;
     const struct drm_mode_config_helper_funcs *funcs;
     struct drm_crtc_state *new_crtc_state;
     struct drm_crtc *crtc;
     ktime_t start;
     s64 commit_time_ms;
     unsigned int i, new_self_refresh_mask = 0;
 
     funcs = dev->mode_config.helper_private;
 
     /*
      * We're measuring the _entire_ commit, so the time will vary depending
      * on how many fences and objects are involved. For the purposes of self
      * refresh, this is desirable since it'll give us an idea of how
      * congested things are. This will inform our decision on how often we
      * should enter self refresh after idle.
      *
      * These times will be averaged out in the self refresh helpers to avoid
      * overreacting over one outlier frame
      */
     start = ktime_get();
 
     drm_atomic_helper_wait_for_fences(dev, old_state, false);
 
     drm_atomic_helper_wait_for_dependencies(old_state);
 
     /*
      * We cannot safely access new_crtc_state after
      * drm_atomic_helper_commit_hw_done() so figure out which crtc's have
      * self-refresh active beforehand:
      */
     for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i)
         if (new_crtc_state->self_refresh_active)
             new_self_refresh_mask |= BIT(i);
 
     if (funcs && funcs->atomic_commit_tail)
         funcs->atomic_commit_tail(old_state);
     else
         drm_atomic_helper_commit_tail(old_state);
 
     commit_time_ms = ktime_ms_delta(ktime_get(), start);
     if (commit_time_ms > 0)
         drm_self_refresh_helper_update_avg_times(old_state,
                          (unsigned long)commit_time_ms,
                          new_self_refresh_mask);
 
     drm_atomic_helper_commit_cleanup_done(old_state);
 
     drm_atomic_state_put(old_state);
 }
 
 static void commit_work(struct work_struct *work)
 {
     struct drm_atomic_state *state = container_of(work,
                               struct drm_atomic_state,
                               commit_work);
     commit_tail(state);
 }
 
 /**
  * drm_atomic_helper_async_check - check if state can be committed asynchronously
  * @dev: DRM device
  * @state: the driver state object
  *
  * This helper will check if it is possible to commit the state asynchronously.
  * Async commits are not supposed to swap the states like normal sync commits
  * but just do in-place changes on the current state.
  *
  * It will return 0 if the commit can happen in an asynchronous fashion or error
  * if not. Note that error just mean it can't be committed asynchronously, if it
  * fails the commit should be treated like a normal synchronous commit.
  */
 int drm_atomic_helper_async_check(struct drm_device *dev,
                    struct drm_atomic_state *state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *crtc_state;
     struct drm_plane *plane = NULL;
     struct drm_plane_state *old_plane_state = NULL;
     struct drm_plane_state *new_plane_state = NULL;
     const struct drm_plane_helper_funcs *funcs;
     int i, n_planes = 0;
 
     for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
         if (drm_atomic_crtc_needs_modeset(crtc_state))
             return -EINVAL;
     }
 
     for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i)
         n_planes++;
 
     /* FIXME: we support only single plane updates for now */
     if (n_planes != 1)
         return -EINVAL;
 
     if (!new_plane_state->crtc ||
         old_plane_state->crtc != new_plane_state->crtc)
         return -EINVAL;
 
     funcs = plane->helper_private;
     if (!funcs->atomic_async_update)
         return -EINVAL;
 
     if (new_plane_state->fence)
         return -EINVAL;
 
     /*
      * Don't do an async update if there is an outstanding commit modifying
      * the plane.  This prevents our async update's changes from getting
      * overridden by a previous synchronous update's state.
      */
     if (old_plane_state->commit &&
         !try_wait_for_completion(&old_plane_state->commit->hw_done)) {
         drm_dbg_atomic(dev,
                    "[PLANE:%d:%s] inflight previous commit preventing async commit\n",
                    plane->base.id, plane->name);
         return -EBUSY;
     }
 
     return funcs->atomic_async_check(plane, state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_async_check);
 
 /**
  * drm_atomic_helper_async_commit - commit state asynchronously
  * @dev: DRM device
  * @state: the driver state object
  *
  * This function commits a state asynchronously, i.e., not vblank
  * synchronized. It should be used on a state only when
  * drm_atomic_async_check() succeeds. Async commits are not supposed to swap
  * the states like normal sync commits, but just do in-place changes on the
  * current state.
  *
  * TODO: Implement full swap instead of doing in-place changes.
  */
 void drm_atomic_helper_async_commit(struct drm_device *dev,
                     struct drm_atomic_state *state)
 {
     struct drm_plane *plane;
     struct drm_plane_state *plane_state;
     const struct drm_plane_helper_funcs *funcs;
     int i;
 
     for_each_new_plane_in_state(state, plane, plane_state, i) {
         struct drm_framebuffer *new_fb = plane_state->fb;
         struct drm_framebuffer *old_fb = plane->state->fb;
 
         funcs = plane->helper_private;
         funcs->atomic_async_update(plane, state);
 
         /*
          * ->atomic_async_update() is supposed to update the
          * plane->state in-place, make sure at least common
          * properties have been properly updated.
          */
         WARN_ON_ONCE(plane->state->fb != new_fb);
         WARN_ON_ONCE(plane->state->crtc_x != plane_state->crtc_x);
         WARN_ON_ONCE(plane->state->crtc_y != plane_state->crtc_y);
         WARN_ON_ONCE(plane->state->src_x != plane_state->src_x);
         WARN_ON_ONCE(plane->state->src_y != plane_state->src_y);
 
         /*
          * Make sure the FBs have been swapped so that cleanups in the
          * new_state performs a cleanup in the old FB.
          */
         WARN_ON_ONCE(plane_state->fb != old_fb);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_async_commit);
 
 /**
  * drm_atomic_helper_commit - commit validated state object
  * @dev: DRM device
  * @state: the driver state object
  * @nonblock: whether nonblocking behavior is requested.
  *
  * This function commits a with drm_atomic_helper_check() pre-validated state
  * object. This can still fail when e.g. the framebuffer reservation fails. This
  * function implements nonblocking commits, using
  * drm_atomic_helper_setup_commit() and related functions.
  *
  * Committing the actual hardware state is done through the
  * &drm_mode_config_helper_funcs.atomic_commit_tail callback, or its default
  * implementation drm_atomic_helper_commit_tail().
  *
  * RETURNS:
  * Zero for success or -errno.
  */
 int drm_atomic_helper_commit(struct drm_device *dev,
                  struct drm_atomic_state *state,
                  bool nonblock)
 {
     int ret;
 
     if (state->async_update) {
         ret = drm_atomic_helper_prepare_planes(dev, state);
         if (ret)
             return ret;
 
         drm_atomic_helper_async_commit(dev, state);
         drm_atomic_helper_cleanup_planes(dev, state);
 
         return 0;
     }
 
     ret = drm_atomic_helper_setup_commit(state, nonblock);
     if (ret)
         return ret;
 
     INIT_WORK(&state->commit_work, commit_work);
 
     ret = drm_atomic_helper_prepare_planes(dev, state);
     if (ret)
         return ret;
 
     if (!nonblock) {
         ret = drm_atomic_helper_wait_for_fences(dev, state, true);
         if (ret)
             goto err;
     }
 
     /*
      * This is the point of no return - everything below never fails except
      * when the hw goes bonghits. Which means we can commit the new state on
      * the software side now.
      */
 
     ret = drm_atomic_helper_swap_state(state, true);
     if (ret)
         goto err;
 
     /*
      * Everything below can be run asynchronously without the need to grab
      * any modeset locks at all under one condition: It must be guaranteed
      * that the asynchronous work has either been cancelled (if the driver
      * supports it, which at least requires that the framebuffers get
      * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
      * before the new state gets committed on the software side with
      * drm_atomic_helper_swap_state().
      *
      * This scheme allows new atomic state updates to be prepared and
      * checked in parallel to the asynchronous completion of the previous
      * update. Which is important since compositors need to figure out the
      * composition of the next frame right after having submitted the
      * current layout.
      *
      * NOTE: Commit work has multiple phases, first hardware commit, then
      * cleanup. We want them to overlap, hence need system_unbound_wq to
      * make sure work items don't artificially stall on each another.
      */
 
     drm_atomic_state_get(state);
     if (nonblock)
         queue_work(system_unbound_wq, &state->commit_work);
     else
         commit_tail(state);
 
     return 0;
 
 err:
     drm_atomic_helper_cleanup_planes(dev, state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit);
 
 /**
  * DOC: implementing nonblocking commit
  *
  * Nonblocking atomic commits should use struct &drm_crtc_commit to sequence
  * different operations against each another. Locks, especially struct
  * &drm_modeset_lock, should not be held in worker threads or any other
  * asynchronous context used to commit the hardware state.
  *
  * drm_atomic_helper_commit() implements the recommended sequence for
  * nonblocking commits, using drm_atomic_helper_setup_commit() internally:
  *
  * 1. Run drm_atomic_helper_prepare_planes(). Since this can fail and we
  * need to propagate out of memory/VRAM errors to userspace, it must be called
  * synchronously.
  *
  * 2. Synchronize with any outstanding nonblocking commit worker threads which
  * might be affected by the new state update. This is handled by
  * drm_atomic_helper_setup_commit().
  *
  * Asynchronous workers need to have sufficient parallelism to be able to run
  * different atomic commits on different CRTCs in parallel. The simplest way to
  * achieve this is by running them on the &system_unbound_wq work queue. Note
  * that drivers are not required to split up atomic commits and run an
  * individual commit in parallel - userspace is supposed to do that if it cares.
  * But it might be beneficial to do that for modesets, since those necessarily
  * must be done as one global operation, and enabling or disabling a CRTC can
  * take a long time. But even that is not required.
  *
  * IMPORTANT: A &drm_atomic_state update for multiple CRTCs is sequenced
  * against all CRTCs therein. Therefore for atomic state updates which only flip
  * planes the driver must not get the struct &drm_crtc_state of unrelated CRTCs
  * in its atomic check code: This would prevent committing of atomic updates to
  * multiple CRTCs in parallel. In general, adding additional state structures
  * should be avoided as much as possible, because this reduces parallelism in
  * (nonblocking) commits, both due to locking and due to commit sequencing
  * requirements.
  *
  * 3. The software state is updated synchronously with
  * drm_atomic_helper_swap_state(). Doing this under the protection of all modeset
  * locks means concurrent callers never see inconsistent state. Note that commit
  * workers do not hold any locks; their access is only coordinated through
  * ordering. If workers would access state only through the pointers in the
  * free-standing state objects (currently not the case for any driver) then even
  * multiple pending commits could be in-flight at the same time.
  *
  * 4. Schedule a work item to do all subsequent steps, using the split-out
  * commit helpers: a) pre-plane commit b) plane commit c) post-plane commit and
  * then cleaning up the framebuffers after the old framebuffer is no longer
  * being displayed. The scheduled work should synchronize against other workers
  * using the &drm_crtc_commit infrastructure as needed. See
  * drm_atomic_helper_setup_commit() for more details.
  */
 
 static int stall_checks(struct drm_crtc *crtc, bool nonblock)
 {
     struct drm_crtc_commit *commit, *stall_commit = NULL;
     bool completed = true;
     int i;
     long ret = 0;
 
     spin_lock(&crtc->commit_lock);
     i = 0;
     list_for_each_entry(commit, &crtc->commit_list, commit_entry) {
         if (i == 0) {
             completed = try_wait_for_completion(&commit->flip_done);
             /*
              * Userspace is not allowed to get ahead of the previous
              * commit with nonblocking ones.
              */
             if (!completed && nonblock) {
                 spin_unlock(&crtc->commit_lock);
                 drm_dbg_atomic(crtc->dev,
                            "[CRTC:%d:%s] busy with a previous commit\n",
                            crtc->base.id, crtc->name);
 
                 return -EBUSY;
             }
         } else if (i == 1) {
             stall_commit = drm_crtc_commit_get(commit);
             break;
         }
 
         i++;
     }
     spin_unlock(&crtc->commit_lock);
 
     if (!stall_commit)
         return 0;
 
     /* We don't want to let commits get ahead of cleanup work too much,
      * stalling on 2nd previous commit means triple-buffer won't ever stall.
      */
     ret = wait_for_completion_interruptible_timeout(&stall_commit->cleanup_done,
                             10*HZ);
     if (ret == 0)
         drm_err(crtc->dev, "[CRTC:%d:%s] cleanup_done timed out\n",
             crtc->base.id, crtc->name);
 
     drm_crtc_commit_put(stall_commit);
 
     return ret < 0 ? ret : 0;
 }
 
 static void release_crtc_commit(struct completion *completion)
 {
     struct drm_crtc_commit *commit = container_of(completion,
                               typeof(*commit),
                               flip_done);
 
     drm_crtc_commit_put(commit);
 }
 
 static void init_commit(struct drm_crtc_commit *commit, struct drm_crtc *crtc)
 {
     init_completion(&commit->flip_done);
     init_completion(&commit->hw_done);
     init_completion(&commit->cleanup_done);
     INIT_LIST_HEAD(&commit->commit_entry);
     kref_init(&commit->ref);
     commit->crtc = crtc;
 }
 
 static struct drm_crtc_commit *
 crtc_or_fake_commit(struct drm_atomic_state *state, struct drm_crtc *crtc)
 {
     if (crtc) {
         struct drm_crtc_state *new_crtc_state;
 
         new_crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
 
         return new_crtc_state->commit;
     }
 
     if (!state->fake_commit) {
         state->fake_commit = kzalloc(sizeof(*state->fake_commit), GFP_KERNEL);
         if (!state->fake_commit)
             return NULL;
 
         init_commit(state->fake_commit, NULL);
     }
 
     return state->fake_commit;
 }
 
 /**
  * drm_atomic_helper_setup_commit - setup possibly nonblocking commit
  * @state: new modeset state to be committed
  * @nonblock: whether nonblocking behavior is requested.
  *
  * This function prepares @state to be used by the atomic helper's support for
  * nonblocking commits. Drivers using the nonblocking commit infrastructure
  * should always call this function from their
  * &drm_mode_config_funcs.atomic_commit hook.
  *
  * Drivers that need to extend the commit setup to private objects can use the
  * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
  *
  * To be able to use this support drivers need to use a few more helper
  * functions. drm_atomic_helper_wait_for_dependencies() must be called before
  * actually committing the hardware state, and for nonblocking commits this call
  * must be placed in the async worker. See also drm_atomic_helper_swap_state()
  * and its stall parameter, for when a driver's commit hooks look at the
  * &drm_crtc.state, &drm_plane.state or &drm_connector.state pointer directly.
  *
  * Completion of the hardware commit step must be signalled using
  * drm_atomic_helper_commit_hw_done(). After this step the driver is not allowed
  * to read or change any permanent software or hardware modeset state. The only
  * exception is state protected by other means than &drm_modeset_lock locks.
  * Only the free standing @state with pointers to the old state structures can
  * be inspected, e.g. to clean up old buffers using
  * drm_atomic_helper_cleanup_planes().
  *
  * At the very end, before cleaning up @state drivers must call
  * drm_atomic_helper_commit_cleanup_done().
  *
  * This is all implemented by in drm_atomic_helper_commit(), giving drivers a
  * complete and easy-to-use default implementation of the atomic_commit() hook.
  *
  * The tracking of asynchronously executed and still pending commits is done
  * using the core structure &drm_crtc_commit.
  *
  * By default there's no need to clean up resources allocated by this function
  * explicitly: drm_atomic_state_default_clear() will take care of that
  * automatically.
  *
  * Returns:
  *
  * 0 on success. -EBUSY when userspace schedules nonblocking commits too fast,
  * -ENOMEM on allocation failures and -EINTR when a signal is pending.
  */
 int drm_atomic_helper_setup_commit(struct drm_atomic_state *state,
                    bool nonblock)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     struct drm_connector *conn;
     struct drm_connector_state *old_conn_state, *new_conn_state;
     struct drm_plane *plane;
     struct drm_plane_state *old_plane_state, *new_plane_state;
     struct drm_crtc_commit *commit;
     const struct drm_mode_config_helper_funcs *funcs;
     int i, ret;
 
     funcs = state->dev->mode_config.helper_private;
 
     for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
         commit = kzalloc(sizeof(*commit), GFP_KERNEL);
         if (!commit)
             return -ENOMEM;
 
         init_commit(commit, crtc);
 
         new_crtc_state->commit = commit;
 
         ret = stall_checks(crtc, nonblock);
         if (ret)
             return ret;
 
         /*
          * Drivers only send out events when at least either current or
          * new CRTC state is active. Complete right away if everything
          * stays off.
          */
         if (!old_crtc_state->active && !new_crtc_state->active) {
             complete_all(&commit->flip_done);
             continue;
         }
 
         /* Legacy cursor updates are fully unsynced. */
         if (state->legacy_cursor_update) {
             complete_all(&commit->flip_done);
             continue;
         }
 
         if (!new_crtc_state->event) {
             commit->event = kzalloc(sizeof(*commit->event),
                         GFP_KERNEL);
             if (!commit->event)
                 return -ENOMEM;
 
             new_crtc_state->event = commit->event;
         }
 
         new_crtc_state->event->base.completion = &commit->flip_done;
         new_crtc_state->event->base.completion_release = release_crtc_commit;
         drm_crtc_commit_get(commit);
 
         commit->abort_completion = true;
 
         state->crtcs[i].commit = commit;
         drm_crtc_commit_get(commit);
     }
 
     for_each_oldnew_connector_in_state(state, conn, old_conn_state, new_conn_state, i) {
         /*
          * Userspace is not allowed to get ahead of the previous
          * commit with nonblocking ones.
          */
         if (nonblock && old_conn_state->commit &&
             !try_wait_for_completion(&old_conn_state->commit->flip_done)) {
             drm_dbg_atomic(conn->dev,
                        "[CONNECTOR:%d:%s] busy with a previous commit\n",
                        conn->base.id, conn->name);
 
             return -EBUSY;
         }
 
         /* Always track connectors explicitly for e.g. link retraining. */
         commit = crtc_or_fake_commit(state, new_conn_state->crtc ?: old_conn_state->crtc);
         if (!commit)
             return -ENOMEM;
 
         new_conn_state->commit = drm_crtc_commit_get(commit);
     }
 
     for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
         /*
          * Userspace is not allowed to get ahead of the previous
          * commit with nonblocking ones.
          */
         if (nonblock && old_plane_state->commit &&
             !try_wait_for_completion(&old_plane_state->commit->flip_done)) {
             drm_dbg_atomic(plane->dev,
                        "[PLANE:%d:%s] busy with a previous commit\n",
                        plane->base.id, plane->name);
 
             return -EBUSY;
         }
 
         /* Always track planes explicitly for async pageflip support. */
         commit = crtc_or_fake_commit(state, new_plane_state->crtc ?: old_plane_state->crtc);
         if (!commit)
             return -ENOMEM;
 
         new_plane_state->commit = drm_crtc_commit_get(commit);
     }
 
     if (funcs && funcs->atomic_commit_setup)
         return funcs->atomic_commit_setup(state);
 
     return 0;
 }
 EXPORT_SYMBOL(drm_atomic_helper_setup_commit);
 
 /**
  * drm_atomic_helper_wait_for_dependencies - wait for required preceeding commits
  * @old_state: atomic state object with old state structures
  *
  * This function waits for all preceeding commits that touch the same CRTC as
  * @old_state to both be committed to the hardware (as signalled by
  * drm_atomic_helper_commit_hw_done()) and executed by the hardware (as signalled
  * by calling drm_crtc_send_vblank_event() on the &drm_crtc_state.event).
  *
  * This is part of the atomic helper support for nonblocking commits, see
  * drm_atomic_helper_setup_commit() for an overview.
  */
 void drm_atomic_helper_wait_for_dependencies(struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state;
     struct drm_plane *plane;
     struct drm_plane_state *old_plane_state;
     struct drm_connector *conn;
     struct drm_connector_state *old_conn_state;
     int i;
     long ret;
 
     for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
         ret = drm_crtc_commit_wait(old_crtc_state->commit);
         if (ret)
             drm_err(crtc->dev,
                 "[CRTC:%d:%s] commit wait timed out\n",
                 crtc->base.id, crtc->name);
     }
 
     for_each_old_connector_in_state(old_state, conn, old_conn_state, i) {
         ret = drm_crtc_commit_wait(old_conn_state->commit);
         if (ret)
             drm_err(conn->dev,
                 "[CONNECTOR:%d:%s] commit wait timed out\n",
                 conn->base.id, conn->name);
     }
 
     for_each_old_plane_in_state(old_state, plane, old_plane_state, i) {
         ret = drm_crtc_commit_wait(old_plane_state->commit);
         if (ret)
             drm_err(plane->dev,
                 "[PLANE:%d:%s] commit wait timed out\n",
                 plane->base.id, plane->name);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_wait_for_dependencies);
 
 /**
  * drm_atomic_helper_fake_vblank - fake VBLANK events if needed
  * @old_state: atomic state object with old state structures
  *
  * This function walks all CRTCs and fakes VBLANK events on those with
  * &drm_crtc_state.no_vblank set to true and &drm_crtc_state.event != NULL.
  * The primary use of this function is writeback connectors working in oneshot
  * mode and faking VBLANK events. In this case they only fake the VBLANK event
  * when a job is queued, and any change to the pipeline that does not touch the
  * connector is leading to timeouts when calling
  * drm_atomic_helper_wait_for_vblanks() or
  * drm_atomic_helper_wait_for_flip_done(). In addition to writeback
  * connectors, this function can also fake VBLANK events for CRTCs without
  * VBLANK interrupt.
  *
  * This is part of the atomic helper support for nonblocking commits, see
  * drm_atomic_helper_setup_commit() for an overview.
  */
 void drm_atomic_helper_fake_vblank(struct drm_atomic_state *old_state)
 {
     struct drm_crtc_state *new_crtc_state;
     struct drm_crtc *crtc;
     int i;
 
     for_each_new_crtc_in_state(old_state, crtc, new_crtc_state, i) {
         unsigned long flags;
 
         if (!new_crtc_state->no_vblank)
             continue;
 
         spin_lock_irqsave(&old_state->dev->event_lock, flags);
         if (new_crtc_state->event) {
             drm_crtc_send_vblank_event(crtc,
                            new_crtc_state->event);
             new_crtc_state->event = NULL;
         }
         spin_unlock_irqrestore(&old_state->dev->event_lock, flags);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_fake_vblank);
 
 /**
  * drm_atomic_helper_commit_hw_done - setup possible nonblocking commit
  * @old_state: atomic state object with old state structures
  *
  * This function is used to signal completion of the hardware commit step. After
  * this step the driver is not allowed to read or change any permanent software
  * or hardware modeset state. The only exception is state protected by other
  * means than &drm_modeset_lock locks.
  *
  * Drivers should try to postpone any expensive or delayed cleanup work after
  * this function is called.
  *
  * This is part of the atomic helper support for nonblocking commits, see
  * drm_atomic_helper_setup_commit() for an overview.
  */
 void drm_atomic_helper_commit_hw_done(struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     struct drm_crtc_commit *commit;
     int i;
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         commit = new_crtc_state->commit;
         if (!commit)
             continue;
 
         /*
          * copy new_crtc_state->commit to old_crtc_state->commit,
          * it's unsafe to touch new_crtc_state after hw_done,
          * but we still need to do so in cleanup_done().
          */
         if (old_crtc_state->commit)
             drm_crtc_commit_put(old_crtc_state->commit);
 
         old_crtc_state->commit = drm_crtc_commit_get(commit);
 
         /* backend must have consumed any event by now */
         WARN_ON(new_crtc_state->event);
         complete_all(&commit->hw_done);
     }
 
     if (old_state->fake_commit) {
         complete_all(&old_state->fake_commit->hw_done);
         complete_all(&old_state->fake_commit->flip_done);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_hw_done);
 
 /**
  * drm_atomic_helper_commit_cleanup_done - signal completion of commit
  * @old_state: atomic state object with old state structures
  *
  * This signals completion of the atomic update @old_state, including any
  * cleanup work. If used, it must be called right before calling
  * drm_atomic_state_put().
  *
  * This is part of the atomic helper support for nonblocking commits, see
  * drm_atomic_helper_setup_commit() for an overview.
  */
 void drm_atomic_helper_commit_cleanup_done(struct drm_atomic_state *old_state)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state;
     struct drm_crtc_commit *commit;
     int i;
 
     for_each_old_crtc_in_state(old_state, crtc, old_crtc_state, i) {
         commit = old_crtc_state->commit;
         if (WARN_ON(!commit))
             continue;
 
         complete_all(&commit->cleanup_done);
         WARN_ON(!try_wait_for_completion(&commit->hw_done));
 
         spin_lock(&crtc->commit_lock);
         list_del(&commit->commit_entry);
         spin_unlock(&crtc->commit_lock);
     }
 
     if (old_state->fake_commit) {
         complete_all(&old_state->fake_commit->cleanup_done);
         WARN_ON(!try_wait_for_completion(&old_state->fake_commit->hw_done));
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_cleanup_done);
 
 /**
  * drm_atomic_helper_prepare_planes - prepare plane resources before commit
  * @dev: DRM device
  * @state: atomic state object with new state structures
  *
  * This function prepares plane state, specifically framebuffers, for the new
  * configuration, by calling &drm_plane_helper_funcs.prepare_fb. If any failure
  * is encountered this function will call &drm_plane_helper_funcs.cleanup_fb on
  * any already successfully prepared framebuffer.
  *
  * Returns:
  * 0 on success, negative error code on failure.
  */
 int drm_atomic_helper_prepare_planes(struct drm_device *dev,
                      struct drm_atomic_state *state)
 {
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     struct drm_plane *plane;
     struct drm_plane_state *new_plane_state;
     int ret, i, j;
 
     for_each_new_connector_in_state(state, connector, new_conn_state, i) {
         if (!new_conn_state->writeback_job)
             continue;
 
         ret = drm_writeback_prepare_job(new_conn_state->writeback_job);
         if (ret < 0)
             return ret;
     }
 
     for_each_new_plane_in_state(state, plane, new_plane_state, i) {
         const struct drm_plane_helper_funcs *funcs;
 
         funcs = plane->helper_private;
 
         if (funcs->prepare_fb) {
             ret = funcs->prepare_fb(plane, new_plane_state);
             if (ret)
                 goto fail;
         } else {
             WARN_ON_ONCE(funcs->cleanup_fb);
 
             if (!drm_core_check_feature(dev, DRIVER_GEM))
                 continue;
 
             ret = drm_gem_plane_helper_prepare_fb(plane, new_plane_state);
             if (ret)
                 goto fail;
         }
     }
 
     return 0;
 
 fail:
     for_each_new_plane_in_state(state, plane, new_plane_state, j) {
         const struct drm_plane_helper_funcs *funcs;
 
         if (j >= i)
             continue;
 
         funcs = plane->helper_private;
 
         if (funcs->cleanup_fb)
             funcs->cleanup_fb(plane, new_plane_state);
     }
 
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_prepare_planes);
 
 static bool plane_crtc_active(const struct drm_plane_state *state)
 {
     return state->crtc && state->crtc->state->active;
 }
 
 /**
  * drm_atomic_helper_commit_planes - commit plane state
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  * @flags: flags for committing plane state
  *
  * This function commits the new plane state using the plane and atomic helper
  * functions for planes and CRTCs. It assumes that the atomic state has already
  * been pushed into the relevant object state pointers, since this step can no
  * longer fail.
  *
  * It still requires the global state object @old_state to know which planes and
  * crtcs need to be updated though.
  *
  * Note that this function does all plane updates across all CRTCs in one step.
  * If the hardware can't support this approach look at
  * drm_atomic_helper_commit_planes_on_crtc() instead.
  *
  * Plane parameters can be updated by applications while the associated CRTC is
  * disabled. The DRM/KMS core will store the parameters in the plane state,
  * which will be available to the driver when the CRTC is turned on. As a result
  * most drivers don't need to be immediately notified of plane updates for a
  * disabled CRTC.
  *
  * Unless otherwise needed, drivers are advised to set the ACTIVE_ONLY flag in
  * @flags in order not to receive plane update notifications related to a
  * disabled CRTC. This avoids the need to manually ignore plane updates in
  * driver code when the driver and/or hardware can't or just don't need to deal
  * with updates on disabled CRTCs, for example when supporting runtime PM.
  *
  * Drivers may set the NO_DISABLE_AFTER_MODESET flag in @flags if the relevant
  * display controllers require to disable a CRTC's planes when the CRTC is
  * disabled. This function would skip the &drm_plane_helper_funcs.atomic_disable
  * call for a plane if the CRTC of the old plane state needs a modesetting
  * operation. Of course, the drivers need to disable the planes in their CRTC
  * disable callbacks since no one else would do that.
  *
  * The drm_atomic_helper_commit() default implementation doesn't set the
  * ACTIVE_ONLY flag to most closely match the behaviour of the legacy helpers.
  * This should not be copied blindly by drivers.
  */
 void drm_atomic_helper_commit_planes(struct drm_device *dev,
                      struct drm_atomic_state *old_state,
                      uint32_t flags)
 {
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     struct drm_plane *plane;
     struct drm_plane_state *old_plane_state, *new_plane_state;
     int i;
     bool active_only = flags & DRM_PLANE_COMMIT_ACTIVE_ONLY;
     bool no_disable = flags & DRM_PLANE_COMMIT_NO_DISABLE_AFTER_MODESET;
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         funcs = crtc->helper_private;
 
         if (!funcs || !funcs->atomic_begin)
             continue;
 
         if (active_only && !new_crtc_state->active)
             continue;
 
         funcs->atomic_begin(crtc, old_state);
     }
 
     for_each_oldnew_plane_in_state(old_state, plane, old_plane_state, new_plane_state, i) {
         const struct drm_plane_helper_funcs *funcs;
         bool disabling;
 
         funcs = plane->helper_private;
 
         if (!funcs)
             continue;
 
         disabling = drm_atomic_plane_disabling(old_plane_state,
                                new_plane_state);
 
         if (active_only) {
             /*
              * Skip planes related to inactive CRTCs. If the plane
              * is enabled use the state of the current CRTC. If the
              * plane is being disabled use the state of the old
              * CRTC to avoid skipping planes being disabled on an
              * active CRTC.
              */
             if (!disabling && !plane_crtc_active(new_plane_state))
                 continue;
             if (disabling && !plane_crtc_active(old_plane_state))
                 continue;
         }
 
         /*
          * Special-case disabling the plane if drivers support it.
          */
         if (disabling && funcs->atomic_disable) {
             struct drm_crtc_state *crtc_state;
 
             crtc_state = old_plane_state->crtc->state;
 
             if (drm_atomic_crtc_needs_modeset(crtc_state) &&
                 no_disable)
                 continue;
 
             funcs->atomic_disable(plane, old_state);
         } else if (new_plane_state->crtc || disabling) {
             funcs->atomic_update(plane, old_state);
         }
     }
 
     for_each_oldnew_crtc_in_state(old_state, crtc, old_crtc_state, new_crtc_state, i) {
         const struct drm_crtc_helper_funcs *funcs;
 
         funcs = crtc->helper_private;
 
         if (!funcs || !funcs->atomic_flush)
             continue;
 
         if (active_only && !new_crtc_state->active)
             continue;
 
         funcs->atomic_flush(crtc, old_state);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_planes);
 
 /**
  * drm_atomic_helper_commit_planes_on_crtc - commit plane state for a CRTC
  * @old_crtc_state: atomic state object with the old CRTC state
  *
  * This function commits the new plane state using the plane and atomic helper
  * functions for planes on the specific CRTC. It assumes that the atomic state
  * has already been pushed into the relevant object state pointers, since this
  * step can no longer fail.
  *
  * This function is useful when plane updates should be done CRTC-by-CRTC
  * instead of one global step like drm_atomic_helper_commit_planes() does.
  *
  * This function can only be savely used when planes are not allowed to move
  * between different CRTCs because this function doesn't handle inter-CRTC
  * dependencies. Callers need to ensure that either no such dependencies exist,
  * resolve them through ordering of commit calls or through some other means.
  */
 void
 drm_atomic_helper_commit_planes_on_crtc(struct drm_crtc_state *old_crtc_state)
 {
     const struct drm_crtc_helper_funcs *crtc_funcs;
     struct drm_crtc *crtc = old_crtc_state->crtc;
     struct drm_atomic_state *old_state = old_crtc_state->state;
     struct drm_crtc_state *new_crtc_state =
         drm_atomic_get_new_crtc_state(old_state, crtc);
     struct drm_plane *plane;
     unsigned int plane_mask;
 
     plane_mask = old_crtc_state->plane_mask;
     plane_mask |= new_crtc_state->plane_mask;
 
     crtc_funcs = crtc->helper_private;
     if (crtc_funcs && crtc_funcs->atomic_begin)
         crtc_funcs->atomic_begin(crtc, old_state);
 
     drm_for_each_plane_mask(plane, crtc->dev, plane_mask) {
         struct drm_plane_state *old_plane_state =
             drm_atomic_get_old_plane_state(old_state, plane);
         struct drm_plane_state *new_plane_state =
             drm_atomic_get_new_plane_state(old_state, plane);
         const struct drm_plane_helper_funcs *plane_funcs;
 
         plane_funcs = plane->helper_private;
 
         if (!old_plane_state || !plane_funcs)
             continue;
 
         WARN_ON(new_plane_state->crtc &&
             new_plane_state->crtc != crtc);
 
         if (drm_atomic_plane_disabling(old_plane_state, new_plane_state) &&
             plane_funcs->atomic_disable)
             plane_funcs->atomic_disable(plane, old_state);
         else if (new_plane_state->crtc ||
              drm_atomic_plane_disabling(old_plane_state, new_plane_state))
             plane_funcs->atomic_update(plane, old_state);
     }
 
     if (crtc_funcs && crtc_funcs->atomic_flush)
         crtc_funcs->atomic_flush(crtc, old_state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_planes_on_crtc);
 
 /**
  * drm_atomic_helper_disable_planes_on_crtc - helper to disable CRTC's planes
  * @old_crtc_state: atomic state object with the old CRTC state
  * @atomic: if set, synchronize with CRTC's atomic_begin/flush hooks
  *
  * Disables all planes associated with the given CRTC. This can be
  * used for instance in the CRTC helper atomic_disable callback to disable
  * all planes.
  *
  * If the atomic-parameter is set the function calls the CRTC's
  * atomic_begin hook before and atomic_flush hook after disabling the
  * planes.
  *
  * It is a bug to call this function without having implemented the
  * &drm_plane_helper_funcs.atomic_disable plane hook.
  */
 void
 drm_atomic_helper_disable_planes_on_crtc(struct drm_crtc_state *old_crtc_state,
                      bool atomic)
 {
     struct drm_crtc *crtc = old_crtc_state->crtc;
     const struct drm_crtc_helper_funcs *crtc_funcs =
         crtc->helper_private;
     struct drm_plane *plane;
 
     if (atomic && crtc_funcs && crtc_funcs->atomic_begin)
         crtc_funcs->atomic_begin(crtc, NULL);
 
     drm_atomic_crtc_state_for_each_plane(plane, old_crtc_state) {
         const struct drm_plane_helper_funcs *plane_funcs =
             plane->helper_private;
 
         if (!plane_funcs)
             continue;
 
         WARN_ON(!plane_funcs->atomic_disable);
         if (plane_funcs->atomic_disable)
             plane_funcs->atomic_disable(plane, NULL);
     }
 
     if (atomic && crtc_funcs && crtc_funcs->atomic_flush)
         crtc_funcs->atomic_flush(crtc, NULL);
 }
 EXPORT_SYMBOL(drm_atomic_helper_disable_planes_on_crtc);
 
 /**
  * drm_atomic_helper_cleanup_planes - cleanup plane resources after commit
  * @dev: DRM device
  * @old_state: atomic state object with old state structures
  *
  * This function cleans up plane state, specifically framebuffers, from the old
  * configuration. Hence the old configuration must be perserved in @old_state to
  * be able to call this function.
  *
  * This function must also be called on the new state when the atomic update
  * fails at any point after calling drm_atomic_helper_prepare_planes().
  */
 void drm_atomic_helper_cleanup_planes(struct drm_device *dev,
                       struct drm_atomic_state *old_state)
 {
     struct drm_plane *plane;
     struct drm_plane_state *old_plane_state, *new_plane_state;
     int i;
 
     for_each_oldnew_plane_in_state(old_state, plane, old_plane_state, new_plane_state, i) {
         const struct drm_plane_helper_funcs *funcs;
         struct drm_plane_state *plane_state;
 
         /*
          * This might be called before swapping when commit is aborted,
          * in which case we have to cleanup the new state.
          */
         if (old_plane_state == plane->state)
             plane_state = new_plane_state;
         else
             plane_state = old_plane_state;
 
         funcs = plane->helper_private;
 
         if (funcs->cleanup_fb)
             funcs->cleanup_fb(plane, plane_state);
     }
 }
 EXPORT_SYMBOL(drm_atomic_helper_cleanup_planes);
 
 /**
  * drm_atomic_helper_swap_state - store atomic state into current sw state
  * @state: atomic state
  * @stall: stall for preceding commits
  *
  * This function stores the atomic state into the current state pointers in all
  * driver objects. It should be called after all failing steps have been done
  * and succeeded, but before the actual hardware state is committed.
  *
  * For cleanup and error recovery the current state for all changed objects will
  * be swapped into @state.
  *
  * With that sequence it fits perfectly into the plane prepare/cleanup sequence:
  *
  * 1. Call drm_atomic_helper_prepare_planes() with the staged atomic state.
  *
  * 2. Do any other steps that might fail.
  *
  * 3. Put the staged state into the current state pointers with this function.
  *
  * 4. Actually commit the hardware state.
  *
  * 5. Call drm_atomic_helper_cleanup_planes() with @state, which since step 3
  * contains the old state. Also do any other cleanup required with that state.
  *
  * @stall must be set when nonblocking commits for this driver directly access
  * the &drm_plane.state, &drm_crtc.state or &drm_connector.state pointer. With
  * the current atomic helpers this is almost always the case, since the helpers
  * don't pass the right state structures to the callbacks.
  *
  * Returns:
  *
  * Returns 0 on success. Can return -ERESTARTSYS when @stall is true and the
  * waiting for the previous commits has been interrupted.
  */
 int drm_atomic_helper_swap_state(struct drm_atomic_state *state,
                   bool stall)
 {
     int i, ret;
     struct drm_connector *connector;
     struct drm_connector_state *old_conn_state, *new_conn_state;
     struct drm_crtc *crtc;
     struct drm_crtc_state *old_crtc_state, *new_crtc_state;
     struct drm_plane *plane;
     struct drm_plane_state *old_plane_state, *new_plane_state;
     struct drm_crtc_commit *commit;
     struct drm_private_obj *obj;
     struct drm_private_state *old_obj_state, *new_obj_state;
 
     if (stall) {
         /*
          * We have to stall for hw_done here before
          * drm_atomic_helper_wait_for_dependencies() because flip
          * depth > 1 is not yet supported by all drivers. As long as
          * obj->state is directly dereferenced anywhere in the drivers
          * atomic_commit_tail function, then it's unsafe to swap state
          * before drm_atomic_helper_commit_hw_done() is called.
          */
 
         for_each_old_crtc_in_state(state, crtc, old_crtc_state, i) {
             commit = old_crtc_state->commit;
 
             if (!commit)
                 continue;
 
             ret = wait_for_completion_interruptible(&commit->hw_done);
             if (ret)
                 return ret;
         }
 
         for_each_old_connector_in_state(state, connector, old_conn_state, i) {
             commit = old_conn_state->commit;
 
             if (!commit)
                 continue;
 
             ret = wait_for_completion_interruptible(&commit->hw_done);
             if (ret)
                 return ret;
         }
 
         for_each_old_plane_in_state(state, plane, old_plane_state, i) {
             commit = old_plane_state->commit;
 
             if (!commit)
                 continue;
 
             ret = wait_for_completion_interruptible(&commit->hw_done);
             if (ret)
                 return ret;
         }
     }
 
     for_each_oldnew_connector_in_state(state, connector, old_conn_state, new_conn_state, i) {
         WARN_ON(connector->state != old_conn_state);
 
         old_conn_state->state = state;
         new_conn_state->state = NULL;
 
         state->connectors[i].state = old_conn_state;
         connector->state = new_conn_state;
     }
 
     for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
         WARN_ON(crtc->state != old_crtc_state);
 
         old_crtc_state->state = state;
         new_crtc_state->state = NULL;
 
         state->crtcs[i].state = old_crtc_state;
         crtc->state = new_crtc_state;
 
         if (new_crtc_state->commit) {
             spin_lock(&crtc->commit_lock);
             list_add(&new_crtc_state->commit->commit_entry,
                  &crtc->commit_list);
             spin_unlock(&crtc->commit_lock);
 
             new_crtc_state->commit->event = NULL;
         }
     }
 
     for_each_oldnew_plane_in_state(state, plane, old_plane_state, new_plane_state, i) {
         WARN_ON(plane->state != old_plane_state);
 
         old_plane_state->state = state;
         new_plane_state->state = NULL;
 
         state->planes[i].state = old_plane_state;
         plane->state = new_plane_state;
     }
 
     for_each_oldnew_private_obj_in_state(state, obj, old_obj_state, new_obj_state, i) {
         WARN_ON(obj->state != old_obj_state);
 
         old_obj_state->state = state;
         new_obj_state->state = NULL;
 
         state->private_objs[i].state = old_obj_state;
         obj->state = new_obj_state;
     }
 
     return 0;
 }
 EXPORT_SYMBOL(drm_atomic_helper_swap_state);
 
 /**
  * drm_atomic_helper_update_plane - Helper for primary plane update using atomic
  * @plane: plane object to update
  * @crtc: owning CRTC of owning plane
  * @fb: framebuffer to flip onto plane
  * @crtc_x: x offset of primary plane on @crtc
  * @crtc_y: y offset of primary plane on @crtc
  * @crtc_w: width of primary plane rectangle on @crtc
  * @crtc_h: height of primary plane rectangle on @crtc
  * @src_x: x offset of @fb for panning
  * @src_y: y offset of @fb for panning
  * @src_w: width of source rectangle in @fb
  * @src_h: height of source rectangle in @fb
  * @ctx: lock acquire context
  *
  * Provides a default plane update handler using the atomic driver interface.
  *
  * RETURNS:
  * Zero on success, error code on failure
  */
 int drm_atomic_helper_update_plane(struct drm_plane *plane,
                    struct drm_crtc *crtc,
                    struct drm_framebuffer *fb,
                    int crtc_x, int crtc_y,
                    unsigned int crtc_w, unsigned int crtc_h,
                    uint32_t src_x, uint32_t src_y,
                    uint32_t src_w, uint32_t src_h,
                    struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_atomic_state *state;
     struct drm_plane_state *plane_state;
     int ret = 0;
 
     state = drm_atomic_state_alloc(plane->dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
     plane_state = drm_atomic_get_plane_state(state, plane);
     if (IS_ERR(plane_state)) {
         ret = PTR_ERR(plane_state);
         goto fail;
     }
 
     ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
     if (ret != 0)
         goto fail;
     drm_atomic_set_fb_for_plane(plane_state, fb);
     plane_state->crtc_x = crtc_x;
     plane_state->crtc_y = crtc_y;
     plane_state->crtc_w = crtc_w;
     plane_state->crtc_h = crtc_h;
     plane_state->src_x = src_x;
     plane_state->src_y = src_y;
     plane_state->src_w = src_w;
     plane_state->src_h = src_h;
 
     if (plane == crtc->cursor)
         state->legacy_cursor_update = true;
 
     ret = drm_atomic_commit(state);
 fail:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_update_plane);
 
 /**
  * drm_atomic_helper_disable_plane - Helper for primary plane disable using * atomic
  * @plane: plane to disable
  * @ctx: lock acquire context
  *
  * Provides a default plane disable handler using the atomic driver interface.
  *
  * RETURNS:
  * Zero on success, error code on failure
  */
 int drm_atomic_helper_disable_plane(struct drm_plane *plane,
                     struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_atomic_state *state;
     struct drm_plane_state *plane_state;
     int ret = 0;
 
     state = drm_atomic_state_alloc(plane->dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
     plane_state = drm_atomic_get_plane_state(state, plane);
     if (IS_ERR(plane_state)) {
         ret = PTR_ERR(plane_state);
         goto fail;
     }
 
     if (plane_state->crtc && plane_state->crtc->cursor == plane)
         plane_state->state->legacy_cursor_update = true;
 
     ret = __drm_atomic_helper_disable_plane(plane, plane_state);
     if (ret != 0)
         goto fail;
 
     ret = drm_atomic_commit(state);
 fail:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_disable_plane);
 
 /**
  * drm_atomic_helper_set_config - set a new config from userspace
  * @set: mode set configuration
  * @ctx: lock acquisition context
  *
  * Provides a default CRTC set_config handler using the atomic driver interface.
  *
  * NOTE: For backwards compatibility with old userspace this automatically
  * resets the "link-status" property to GOOD, to force any link
  * re-training. The SETCRTC ioctl does not define whether an update does
  * need a full modeset or just a plane update, hence we're allowed to do
  * that. See also drm_connector_set_link_status_property().
  *
  * Returns:
  * Returns 0 on success, negative errno numbers on failure.
  */
 int drm_atomic_helper_set_config(struct drm_mode_set *set,
                  struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_atomic_state *state;
     struct drm_crtc *crtc = set->crtc;
     int ret = 0;
 
     state = drm_atomic_state_alloc(crtc->dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
     ret = __drm_atomic_helper_set_config(set, state);
     if (ret != 0)
         goto fail;
 
     ret = handle_conflicting_encoders(state, true);
     if (ret)
         goto fail;
 
     ret = drm_atomic_commit(state);
 
 fail:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_set_config);
 
 /**
  * drm_atomic_helper_disable_all - disable all currently active outputs
  * @dev: DRM device
  * @ctx: lock acquisition context
  *
  * Loops through all connectors, finding those that aren't turned off and then
  * turns them off by setting their DPMS mode to OFF and deactivating the CRTC
  * that they are connected to.
  *
  * This is used for example in suspend/resume to disable all currently active
  * functions when suspending. If you just want to shut down everything at e.g.
  * driver unload, look at drm_atomic_helper_shutdown().
  *
  * Note that if callers haven't already acquired all modeset locks this might
  * return -EDEADLK, which must be handled by calling drm_modeset_backoff().
  *
  * Returns:
  * 0 on success or a negative error code on failure.
  *
  * See also:
  * drm_atomic_helper_suspend(), drm_atomic_helper_resume() and
  * drm_atomic_helper_shutdown().
  */
 int drm_atomic_helper_disable_all(struct drm_device *dev,
                   struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_atomic_state *state;
     struct drm_connector_state *conn_state;
     struct drm_connector *conn;
     struct drm_plane_state *plane_state;
     struct drm_plane *plane;
     struct drm_crtc_state *crtc_state;
     struct drm_crtc *crtc;
     int ret, i;
 
     state = drm_atomic_state_alloc(dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
 
     drm_for_each_crtc(crtc, dev) {
         crtc_state = drm_atomic_get_crtc_state(state, crtc);
         if (IS_ERR(crtc_state)) {
             ret = PTR_ERR(crtc_state);
             goto free;
         }
 
         crtc_state->active = false;
 
         ret = drm_atomic_set_mode_prop_for_crtc(crtc_state, NULL);
         if (ret < 0)
             goto free;
 
         ret = drm_atomic_add_affected_planes(state, crtc);
         if (ret < 0)
             goto free;
 
         ret = drm_atomic_add_affected_connectors(state, crtc);
         if (ret < 0)
             goto free;
     }
 
     for_each_new_connector_in_state(state, conn, conn_state, i) {
         ret = drm_atomic_set_crtc_for_connector(conn_state, NULL);
         if (ret < 0)
             goto free;
     }
 
     for_each_new_plane_in_state(state, plane, plane_state, i) {
         ret = drm_atomic_set_crtc_for_plane(plane_state, NULL);
         if (ret < 0)
             goto free;
 
         drm_atomic_set_fb_for_plane(plane_state, NULL);
     }
 
     ret = drm_atomic_commit(state);
 free:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_disable_all);
 
 /**
  * drm_atomic_helper_shutdown - shutdown all CRTC
  * @dev: DRM device
  *
  * This shuts down all CRTC, which is useful for driver unloading. Shutdown on
  * suspend should instead be handled with drm_atomic_helper_suspend(), since
  * that also takes a snapshot of the modeset state to be restored on resume.
  *
  * This is just a convenience wrapper around drm_atomic_helper_disable_all(),
  * and it is the atomic version of drm_crtc_force_disable_all().
  */
 void drm_atomic_helper_shutdown(struct drm_device *dev)
 {
     struct drm_modeset_acquire_ctx ctx;
     int ret;
 
     DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, ret);
 
     ret = drm_atomic_helper_disable_all(dev, &ctx);
     if (ret)
         drm_err(dev,
             "Disabling all crtc's during unload failed with %i\n",
             ret);
 
     DRM_MODESET_LOCK_ALL_END(dev, ctx, ret);
 }
 EXPORT_SYMBOL(drm_atomic_helper_shutdown);
 
 /**
  * drm_atomic_helper_duplicate_state - duplicate an atomic state object
  * @dev: DRM device
  * @ctx: lock acquisition context
  *
  * Makes a copy of the current atomic state by looping over all objects and
  * duplicating their respective states. This is used for example by suspend/
  * resume support code to save the state prior to suspend such that it can
  * be restored upon resume.
  *
  * Note that this treats atomic state as persistent between save and restore.
  * Drivers must make sure that this is possible and won't result in confusion
  * or erroneous behaviour.
  *
  * Note that if callers haven't already acquired all modeset locks this might
  * return -EDEADLK, which must be handled by calling drm_modeset_backoff().
  *
  * Returns:
  * A pointer to the copy of the atomic state object on success or an
  * ERR_PTR()-encoded error code on failure.
  *
  * See also:
  * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
  */
 struct drm_atomic_state *
 drm_atomic_helper_duplicate_state(struct drm_device *dev,
                   struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_atomic_state *state;
     struct drm_connector *conn;
     struct drm_connector_list_iter conn_iter;
     struct drm_plane *plane;
     struct drm_crtc *crtc;
     int err = 0;
 
     state = drm_atomic_state_alloc(dev);
     if (!state)
         return ERR_PTR(-ENOMEM);
 
     state->acquire_ctx = ctx;
     state->duplicated = true;
 
     drm_for_each_crtc(crtc, dev) {
         struct drm_crtc_state *crtc_state;
 
         crtc_state = drm_atomic_get_crtc_state(state, crtc);
         if (IS_ERR(crtc_state)) {
             err = PTR_ERR(crtc_state);
             goto free;
         }
     }
 
     drm_for_each_plane(plane, dev) {
         struct drm_plane_state *plane_state;
 
         plane_state = drm_atomic_get_plane_state(state, plane);
         if (IS_ERR(plane_state)) {
             err = PTR_ERR(plane_state);
             goto free;
         }
     }
 
     drm_connector_list_iter_begin(dev, &conn_iter);
     drm_for_each_connector_iter(conn, &conn_iter) {
         struct drm_connector_state *conn_state;
 
         conn_state = drm_atomic_get_connector_state(state, conn);
         if (IS_ERR(conn_state)) {
             err = PTR_ERR(conn_state);
             drm_connector_list_iter_end(&conn_iter);
             goto free;
         }
     }
     drm_connector_list_iter_end(&conn_iter);
 
     /* clear the acquire context so that it isn't accidentally reused */
     state->acquire_ctx = NULL;
 
 free:
     if (err < 0) {
         drm_atomic_state_put(state);
         state = ERR_PTR(err);
     }
 
     return state;
 }
 EXPORT_SYMBOL(drm_atomic_helper_duplicate_state);
 
 /**
  * drm_atomic_helper_suspend - subsystem-level suspend helper
  * @dev: DRM device
  *
  * Duplicates the current atomic state, disables all active outputs and then
  * returns a pointer to the original atomic state to the caller. Drivers can
  * pass this pointer to the drm_atomic_helper_resume() helper upon resume to
  * restore the output configuration that was active at the time the system
  * entered suspend.
  *
  * Note that it is potentially unsafe to use this. The atomic state object
  * returned by this function is assumed to be persistent. Drivers must ensure
  * that this holds true. Before calling this function, drivers must make sure
  * to suspend fbdev emulation so that nothing can be using the device.
  *
  * Returns:
  * A pointer to a copy of the state before suspend on success or an ERR_PTR()-
  * encoded error code on failure. Drivers should store the returned atomic
  * state object and pass it to the drm_atomic_helper_resume() helper upon
  * resume.
  *
  * See also:
  * drm_atomic_helper_duplicate_state(), drm_atomic_helper_disable_all(),
  * drm_atomic_helper_resume(), drm_atomic_helper_commit_duplicated_state()
  */
 struct drm_atomic_state *drm_atomic_helper_suspend(struct drm_device *dev)
 {
     struct drm_modeset_acquire_ctx ctx;
     struct drm_atomic_state *state;
     int err;
 
     /* This can never be returned, but it makes the compiler happy */
     state = ERR_PTR(-EINVAL);
 
     DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, err);
 
     state = drm_atomic_helper_duplicate_state(dev, &ctx);
     if (IS_ERR(state))
         goto unlock;
 
     err = drm_atomic_helper_disable_all(dev, &ctx);
     if (err < 0) {
         drm_atomic_state_put(state);
         state = ERR_PTR(err);
         goto unlock;
     }
 
 unlock:
     DRM_MODESET_LOCK_ALL_END(dev, ctx, err);
     if (err)
         return ERR_PTR(err);
 
     return state;
 }
 EXPORT_SYMBOL(drm_atomic_helper_suspend);
 
 /**
  * drm_atomic_helper_commit_duplicated_state - commit duplicated state
  * @state: duplicated atomic state to commit
  * @ctx: pointer to acquire_ctx to use for commit.
  *
  * The state returned by drm_atomic_helper_duplicate_state() and
  * drm_atomic_helper_suspend() is partially invalid, and needs to
  * be fixed up before commit.
  *
  * Returns:
  * 0 on success or a negative error code on failure.
  *
  * See also:
  * drm_atomic_helper_suspend()
  */
 int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state,
                           struct drm_modeset_acquire_ctx *ctx)
 {
     int i, ret;
     struct drm_plane *plane;
     struct drm_plane_state *new_plane_state;
     struct drm_connector *connector;
     struct drm_connector_state *new_conn_state;
     struct drm_crtc *crtc;
     struct drm_crtc_state *new_crtc_state;
 
     state->acquire_ctx = ctx;
 
     for_each_new_plane_in_state(state, plane, new_plane_state, i)
         state->planes[i].old_state = plane->state;
 
     for_each_new_crtc_in_state(state, crtc, new_crtc_state, i)
         state->crtcs[i].old_state = crtc->state;
 
     for_each_new_connector_in_state(state, connector, new_conn_state, i)
         state->connectors[i].old_state = connector->state;
 
     ret = drm_atomic_commit(state);
 
     state->acquire_ctx = NULL;
 
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_commit_duplicated_state);
 
 /**
  * drm_atomic_helper_resume - subsystem-level resume helper
  * @dev: DRM device
  * @state: atomic state to resume to
  *
  * Calls drm_mode_config_reset() to synchronize hardware and software states,
  * grabs all modeset locks and commits the atomic state object. This can be
  * used in conjunction with the drm_atomic_helper_suspend() helper to
  * implement suspend/resume for drivers that support atomic mode-setting.
  *
  * Returns:
  * 0 on success or a negative error code on failure.
  *
  * See also:
  * drm_atomic_helper_suspend()
  */
 int drm_atomic_helper_resume(struct drm_device *dev,
                  struct drm_atomic_state *state)
 {
     struct drm_modeset_acquire_ctx ctx;
     int err;
 
     drm_mode_config_reset(dev);
 
     DRM_MODESET_LOCK_ALL_BEGIN(dev, ctx, 0, err);
 
     err = drm_atomic_helper_commit_duplicated_state(state, &ctx);
 
     DRM_MODESET_LOCK_ALL_END(dev, ctx, err);
     drm_atomic_state_put(state);
 
     return err;
 }
 EXPORT_SYMBOL(drm_atomic_helper_resume);
 
 static int page_flip_common(struct drm_atomic_state *state,
                 struct drm_crtc *crtc,
                 struct drm_framebuffer *fb,
                 struct drm_pending_vblank_event *event,
                 uint32_t flags)
 {
     struct drm_plane *plane = crtc->primary;
     struct drm_plane_state *plane_state;
     struct drm_crtc_state *crtc_state;
     int ret = 0;
 
     crtc_state = drm_atomic_get_crtc_state(state, crtc);
     if (IS_ERR(crtc_state))
         return PTR_ERR(crtc_state);
 
     crtc_state->event = event;
     crtc_state->async_flip = flags & DRM_MODE_PAGE_FLIP_ASYNC;
 
     plane_state = drm_atomic_get_plane_state(state, plane);
     if (IS_ERR(plane_state))
         return PTR_ERR(plane_state);
 
     ret = drm_atomic_set_crtc_for_plane(plane_state, crtc);
     if (ret != 0)
         return ret;
     drm_atomic_set_fb_for_plane(plane_state, fb);
 
     /* Make sure we don't accidentally do a full modeset. */
     state->allow_modeset = false;
     if (!crtc_state->active) {
         drm_dbg_atomic(crtc->dev,
                    "[CRTC:%d:%s] disabled, rejecting legacy flip\n",
                    crtc->base.id, crtc->name);
         return -EINVAL;
     }
 
     return ret;
 }
 
 /**
  * drm_atomic_helper_page_flip - execute a legacy page flip
  * @crtc: DRM CRTC
  * @fb: DRM framebuffer
  * @event: optional DRM event to signal upon completion
  * @flags: flip flags for non-vblank sync'ed updates
  * @ctx: lock acquisition context
  *
  * Provides a default &drm_crtc_funcs.page_flip implementation
  * using the atomic driver interface.
  *
  * Returns:
  * Returns 0 on success, negative errno numbers on failure.
  *
  * See also:
  * drm_atomic_helper_page_flip_target()
  */
 int drm_atomic_helper_page_flip(struct drm_crtc *crtc,
                 struct drm_framebuffer *fb,
                 struct drm_pending_vblank_event *event,
                 uint32_t flags,
                 struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_plane *plane = crtc->primary;
     struct drm_atomic_state *state;
     int ret = 0;
 
     state = drm_atomic_state_alloc(plane->dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
 
     ret = page_flip_common(state, crtc, fb, event, flags);
     if (ret != 0)
         goto fail;
 
     ret = drm_atomic_nonblocking_commit(state);
 fail:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_page_flip);
 
 /**
  * drm_atomic_helper_page_flip_target - do page flip on target vblank period.
  * @crtc: DRM CRTC
  * @fb: DRM framebuffer
  * @event: optional DRM event to signal upon completion
  * @flags: flip flags for non-vblank sync'ed updates
  * @target: specifying the target vblank period when the flip to take effect
  * @ctx: lock acquisition context
  *
  * Provides a default &drm_crtc_funcs.page_flip_target implementation.
  * Similar to drm_atomic_helper_page_flip() with extra parameter to specify
  * target vblank period to flip.
  *
  * Returns:
  * Returns 0 on success, negative errno numbers on failure.
  */
 int drm_atomic_helper_page_flip_target(struct drm_crtc *crtc,
                        struct drm_framebuffer *fb,
                        struct drm_pending_vblank_event *event,
                        uint32_t flags,
                        uint32_t target,
                        struct drm_modeset_acquire_ctx *ctx)
 {
     struct drm_plane *plane = crtc->primary;
     struct drm_atomic_state *state;
     struct drm_crtc_state *crtc_state;
     int ret = 0;
 
     state = drm_atomic_state_alloc(plane->dev);
     if (!state)
         return -ENOMEM;
 
     state->acquire_ctx = ctx;
 
     ret = page_flip_common(state, crtc, fb, event, flags);
     if (ret != 0)
         goto fail;
 
     crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
     if (WARN_ON(!crtc_state)) {
         ret = -EINVAL;
         goto fail;
     }
     crtc_state->target_vblank = target;
 
     ret = drm_atomic_nonblocking_commit(state);
 fail:
     drm_atomic_state_put(state);
     return ret;
 }
 EXPORT_SYMBOL(drm_atomic_helper_page_flip_target);
 
 /**
  * drm_atomic_helper_bridge_propagate_bus_fmt() - Propagate output format to
  *                        the input end of a bridge
  * @bridge: bridge control structure
  * @bridge_state: new bridge state
  * @crtc_state: new CRTC state
  * @conn_state: new connector state
  * @output_fmt: tested output bus format
  * @num_input_fmts: will contain the size of the returned array
  *
  * This helper is a pluggable implementation of the
  * &drm_bridge_funcs.atomic_get_input_bus_fmts operation for bridges that don't
  * modify the bus configuration between their input and their output. It
  * returns an array of input formats with a single element set to @output_fmt.
  *
  * RETURNS:
  * a valid format array of size @num_input_fmts, or NULL if the allocation
  * failed
  */
 u32 *
 drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
                     struct drm_bridge_state *bridge_state,
                     struct drm_crtc_state *crtc_state,
                     struct drm_connector_state *conn_state,
                     u32 output_fmt,
                     unsigned int *num_input_fmts)
 {
     u32 *input_fmts;
 
     input_fmts = kzalloc(sizeof(*input_fmts), GFP_KERNEL);
     if (!input_fmts) {
         *num_input_fmts = 0;
         return NULL;
     }
 
     *num_input_fmts = 1;
     input_fmts[0] = output_fmt;
     return input_fmts;
 }
 EXPORT_SYMBOL(drm_atomic_helper_bridge_propagate_bus_fmt);