include/drm/drm_vblank.h

0001 /*
0002  * Copyright 2016 Intel Corp.
0003  *
0004  * Permission is hereby granted, free of charge, to any person obtaining a
0005  * copy of this software and associated documentation files (the "Software"),
0006  * to deal in the Software without restriction, including without limitation
0007  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0008  * and/or sell copies of the Software, and to permit persons to whom the
0009  * Software is furnished to do so, subject to the following conditions:
0010  *
0011  * The above copyright notice and this permission notice (including the next
0012  * paragraph) shall be included in all copies or substantial portions of the
0013  * Software.
0014  *
0015  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0016  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0017  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0018  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
0019  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0020  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0021  * OTHER DEALINGS IN THE SOFTWARE.
0022  */
0023
0024 #ifndef _DRM_VBLANK_H_
0025 #define _DRM_VBLANK_H_
0026
0027 #include <linux/seqlock.h>
0028 #include <linux/idr.h>
0029 #include <linux/poll.h>
0030 #include <linux/kthread.h>
0031
0032 #include <drm/drm_file.h>
0033 #include <drm/drm_modes.h>
0034
0035 struct drm_device;
0036 struct drm_crtc;
0037 struct drm_vblank_work;
0038
0039 /**
0040  * struct drm_pending_vblank_event - pending vblank event tracking
0041  */
0042 struct drm_pending_vblank_event {
0043     /**
0044      * @base: Base structure for tracking pending DRM events.
0045      */
0046     struct drm_pending_event base;
0047     /**
0048      * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
0049      */
0050     unsigned int pipe;
0051     /**
0052      * @sequence: frame event should be triggered at
0053      */
0054     u64 sequence;
0055     /**
0056      * @event: Actual event which will be sent to userspace.
0057      */
0058     union {
0059         /**
0060          * @event.base: DRM event base class.
0061          */
0062         struct drm_event base;
0063
0064         /**
0065          * @event.vbl:
0066          *
0067          * Event payload for vblank events, requested through
0068          * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
0069          * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
0070          * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
0071          */
0072         struct drm_event_vblank vbl;
0073
0074         /**
0075          * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
0076          */
0077         struct drm_event_crtc_sequence seq;
0078     } event;
0079 };
0080
0081 /**
0082  * struct drm_vblank_crtc - vblank tracking for a CRTC
0083  *
0084  * This structure tracks the vblank state for one CRTC.
0085  *
0086  * Note that for historical reasons - the vblank handling code is still shared
0087  * with legacy/non-kms drivers - this is a free-standing structure not directly
0088  * connected to &struct drm_crtc. But all public interface functions are taking
0089  * a &struct drm_crtc to hide this implementation detail.
0090  */
0091 struct drm_vblank_crtc {
0092     /**
0093      * @dev: Pointer to the &drm_device.
0094      */
0095     struct drm_device *dev;
0096     /**
0097      * @queue: Wait queue for vblank waiters.
0098      */
0099     wait_queue_head_t queue;
0100     /**
0101      * @disable_timer: Disable timer for the delayed vblank disabling
0102      * hysteresis logic. Vblank disabling is controlled through the
0103      * drm_vblank_offdelay module option and the setting of the
0104      * &drm_device.max_vblank_count value.
0105      */
0106     struct timer_list disable_timer;
0107
0108     /**
0109      * @seqlock: Protect vblank count and time.
0110      */
0111     seqlock_t seqlock;
0112
0113     /**
0114      * @count:
0115      *
0116      * Current software vblank counter.
0117      *
0118      * Note that for a given vblank counter value drm_crtc_handle_vblank()
0119      * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
0120      * provide a barrier: Any writes done before calling
0121      * drm_crtc_handle_vblank() will be visible to callers of the later
0122      * functions, iff the vblank count is the same or a later one.
0123      *
0124      * IMPORTANT: This guarantee requires barriers, therefor never access
0125      * this field directly. Use drm_crtc_vblank_count() instead.
0126      */
0127     atomic64_t count;
0128     /**
0129      * @time: Vblank timestamp corresponding to @count.
0130      */
0131     ktime_t time;
0132
0133     /**
0134      * @refcount: Number of users/waiters of the vblank interrupt. Only when
0135      * this refcount reaches 0 can the hardware interrupt be disabled using
0136      * @disable_timer.
0137      */
0138     atomic_t refcount;
0139     /**
0140      * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
0141      */
0142     u32 last;
0143     /**
0144      * @max_vblank_count:
0145      *
0146      * Maximum value of the vblank registers for this crtc. This value +1
0147      * will result in a wrap-around of the vblank register. It is used
0148      * by the vblank core to handle wrap-arounds.
0149      *
0150      * If set to zero the vblank core will try to guess the elapsed vblanks
0151      * between times when the vblank interrupt is disabled through
0152      * high-precision timestamps. That approach is suffering from small
0153      * races and imprecision over longer time periods, hence exposing a
0154      * hardware vblank counter is always recommended.
0155      *
0156      * This is the runtime configurable per-crtc maximum set through
0157      * drm_crtc_set_max_vblank_count(). If this is used the driver
0158      * must leave the device wide &drm_device.max_vblank_count at zero.
0159      *
0160      * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
0161      */
0162     u32 max_vblank_count;
0163     /**
0164      * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
0165      * For legacy driver bit 2 additionally tracks whether an additional
0166      * temporary vblank reference has been acquired to paper over the
0167      * hardware counter resetting/jumping. KMS drivers should instead just
0168      * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
0169      * save and restore the vblank count.
0170      */
0171     unsigned int inmodeset;
0172     /**
0173      * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
0174      * structure.
0175      */
0176     unsigned int pipe;
0177     /**
0178      * @framedur_ns: Frame/Field duration in ns, used by
0179      * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
0180      * drm_calc_timestamping_constants().
0181      */
0182     int framedur_ns;
0183     /**
0184      * @linedur_ns: Line duration in ns, used by
0185      * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
0186      * drm_calc_timestamping_constants().
0187      */
0188     int linedur_ns;
0189
0190     /**
0191      * @hwmode:
0192      *
0193      * Cache of the current hardware display mode. Only valid when @enabled
0194      * is set. This is used by helpers like
0195      * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
0196      * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
0197      * because that one is really hard to get from interrupt context.
0198      */
0199     struct drm_display_mode hwmode;
0200
0201     /**
0202      * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
0203      * avoid double-disabling and hence corrupting saved state. Needed by
0204      * drivers not using atomic KMS, since those might go through their CRTC
0205      * disabling functions multiple times.
0206      */
0207     bool enabled;
0208
0209     /**
0210      * @worker: The &kthread_worker used for executing vblank works.
0211      */
0212     struct kthread_worker *worker;
0213
0214     /**
0215      * @pending_work: A list of scheduled &drm_vblank_work items that are
0216      * waiting for a future vblank.
0217      */
0218     struct list_head pending_work;
0219
0220     /**
0221      * @work_wait_queue: The wait queue used for signaling that a
0222      * &drm_vblank_work item has either finished executing, or was
0223      * cancelled.
0224      */
0225     wait_queue_head_t work_wait_queue;
0226 };
0227
0228 int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
0229 bool drm_dev_has_vblank(const struct drm_device *dev);
0230 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
0231 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
0232                    ktime_t *vblanktime);
0233 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
0234                    struct drm_pending_vblank_event *e);
0235 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
0236                   struct drm_pending_vblank_event *e);
0237 void drm_vblank_set_event(struct drm_pending_vblank_event *e,
0238               u64 *seq,
0239               ktime_t *now);
0240 bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
0241 bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
0242 int drm_crtc_vblank_get(struct drm_crtc *crtc);
0243 void drm_crtc_vblank_put(struct drm_crtc *crtc);
0244 void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
0245 void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
0246 void drm_crtc_vblank_off(struct drm_crtc *crtc);
0247 void drm_crtc_vblank_reset(struct drm_crtc *crtc);
0248 void drm_crtc_vblank_on(struct drm_crtc *crtc);
0249 u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
0250 void drm_crtc_vblank_restore(struct drm_crtc *crtc);
0251
0252 void drm_calc_timestamping_constants(struct drm_crtc *crtc,
0253                      const struct drm_display_mode *mode);
0254 wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
0255 void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
0256                    u32 max_vblank_count);
0257
0258 /*
0259  * Helpers for struct drm_crtc_funcs
0260  */
0261
0262 typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
0263                              bool in_vblank_irq,
0264                              int *vpos, int *hpos,
0265                              ktime_t *stime,
0266                              ktime_t *etime,
0267                              const struct drm_display_mode *mode);
0268
0269 bool
0270 drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
0271                              int *max_error,
0272                              ktime_t *vblank_time,
0273                              bool in_vblank_irq,
0274                              drm_vblank_get_scanout_position_func get_scanout_position);
0275 bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
0276                          int *max_error,
0277                          ktime_t *vblank_time,
0278                          bool in_vblank_irq);
0279
0280 #endif