OSCL-LXR linux-6.0.1/​drivers/​video/​fbdev/​udlfb.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

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * udlfb.c -- Framebuffer driver for DisplayLink USB controller
  *
  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
  *
  * Layout is based on skeletonfb by James Simmons and Geert Uytterhoeven,
  * usb-skeleton by GregKH.
  *
  * Device-specific portions based on information from Displaylink, with work
  * from Florian Echtler, Henrik Bjerregaard Pedersen, and others.
  */
 
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/usb.h>
 #include <linux/uaccess.h>
 #include <linux/mm.h>
 #include <linux/fb.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <asm/unaligned.h>
 #include <video/udlfb.h>
 #include "edid.h"
 
 static const struct fb_fix_screeninfo dlfb_fix = {
     .id =           "udlfb",
     .type =         FB_TYPE_PACKED_PIXELS,
     .visual =       FB_VISUAL_TRUECOLOR,
     .xpanstep =     0,
     .ypanstep =     0,
     .ywrapstep =    0,
     .accel =        FB_ACCEL_NONE,
 };
 
 static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
         FBINFO_VIRTFB |
         FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
         FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
 
 /*
  * There are many DisplayLink-based graphics products, all with unique PIDs.
  * So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
  * We also require a match on SubClass (0x00) and Protocol (0x00),
  * which is compatible with all known USB 2.0 era graphics chips and firmware,
  * but allows DisplayLink to increment those for any future incompatible chips
  */
 static const struct usb_device_id id_table[] = {
     {.idVendor = 0x17e9,
      .bInterfaceClass = 0xff,
      .bInterfaceSubClass = 0x00,
      .bInterfaceProtocol = 0x00,
      .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
         USB_DEVICE_ID_MATCH_INT_CLASS |
         USB_DEVICE_ID_MATCH_INT_SUBCLASS |
         USB_DEVICE_ID_MATCH_INT_PROTOCOL,
     },
     {},
 };
 MODULE_DEVICE_TABLE(usb, id_table);
 
 /* module options */
 static bool console = true; /* Allow fbcon to open framebuffer */
 static bool fb_defio = true;  /* Detect mmap writes using page faults */
 static bool shadow = true; /* Optionally disable shadow framebuffer */
 static int pixel_limit; /* Optionally force a pixel resolution limit */
 
 struct dlfb_deferred_free {
     struct list_head list;
     void *mem;
 };
 
 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len);
 
 /* dlfb keeps a list of urbs for efficient bulk transfers */
 static void dlfb_urb_completion(struct urb *urb);
 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb);
 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb * urb, size_t len);
 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size);
 static void dlfb_free_urb_list(struct dlfb_data *dlfb);
 
 /*
  * All DisplayLink bulk operations start with 0xAF, followed by specific code
  * All operations are written to buffers which then later get sent to device
  */
 static char *dlfb_set_register(char *buf, u8 reg, u8 val)
 {
     *buf++ = 0xAF;
     *buf++ = 0x20;
     *buf++ = reg;
     *buf++ = val;
     return buf;
 }
 
 static char *dlfb_vidreg_lock(char *buf)
 {
     return dlfb_set_register(buf, 0xFF, 0x00);
 }
 
 static char *dlfb_vidreg_unlock(char *buf)
 {
     return dlfb_set_register(buf, 0xFF, 0xFF);
 }
 
 /*
  * Map FB_BLANK_* to DisplayLink register
  * DLReg FB_BLANK_*
  * ----- -----------------------------
  *  0x00 FB_BLANK_UNBLANK (0)
  *  0x01 FB_BLANK (1)
  *  0x03 FB_BLANK_VSYNC_SUSPEND (2)
  *  0x05 FB_BLANK_HSYNC_SUSPEND (3)
  *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back
  */
 static char *dlfb_blanking(char *buf, int fb_blank)
 {
     u8 reg;
 
     switch (fb_blank) {
     case FB_BLANK_POWERDOWN:
         reg = 0x07;
         break;
     case FB_BLANK_HSYNC_SUSPEND:
         reg = 0x05;
         break;
     case FB_BLANK_VSYNC_SUSPEND:
         reg = 0x03;
         break;
     case FB_BLANK_NORMAL:
         reg = 0x01;
         break;
     default:
         reg = 0x00;
     }
 
     buf = dlfb_set_register(buf, 0x1F, reg);
 
     return buf;
 }
 
 static char *dlfb_set_color_depth(char *buf, u8 selection)
 {
     return dlfb_set_register(buf, 0x00, selection);
 }
 
 static char *dlfb_set_base16bpp(char *wrptr, u32 base)
 {
     /* the base pointer is 16 bits wide, 0x20 is hi byte. */
     wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
     wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
     return dlfb_set_register(wrptr, 0x22, base);
 }
 
 /*
  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
  */
 static char *dlfb_set_base8bpp(char *wrptr, u32 base)
 {
     wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
     wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
     return dlfb_set_register(wrptr, 0x28, base);
 }
 
 static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
 {
     wrptr = dlfb_set_register(wrptr, reg, value >> 8);
     return dlfb_set_register(wrptr, reg+1, value);
 }
 
 /*
  * This is kind of weird because the controller takes some
  * register values in a different byte order than other registers.
  */
 static char *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
 {
     wrptr = dlfb_set_register(wrptr, reg, value);
     return dlfb_set_register(wrptr, reg+1, value >> 8);
 }
 
 /*
  * LFSR is linear feedback shift register. The reason we have this is
  * because the display controller needs to minimize the clock depth of
  * various counters used in the display path. So this code reverses the
  * provided value into the lfsr16 value by counting backwards to get
  * the value that needs to be set in the hardware comparator to get the
  * same actual count. This makes sense once you read above a couple of
  * times and think about it from a hardware perspective.
  */
 static u16 dlfb_lfsr16(u16 actual_count)
 {
     u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
 
     while (actual_count--) {
         lv =     ((lv << 1) |
             (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
             & 0xFFFF;
     }
 
     return (u16) lv;
 }
 
 /*
  * This does LFSR conversion on the value that is to be written.
  * See LFSR explanation above for more detail.
  */
 static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
 {
     return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
 }
 
 /*
  * This takes a standard fbdev screeninfo struct and all of its monitor mode
  * details and converts them into the DisplayLink equivalent register commands.
  */
 static char *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
 {
     u16 xds, yds;
     u16 xde, yde;
     u16 yec;
 
     /* x display start */
     xds = var->left_margin + var->hsync_len;
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
     /* x display end */
     xde = xds + var->xres;
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
 
     /* y display start */
     yds = var->upper_margin + var->vsync_len;
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
     /* y display end */
     yde = yds + var->yres;
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
 
     /* x end count is active + blanking - 1 */
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
             xde + var->right_margin - 1);
 
     /* libdlo hardcodes hsync start to 1 */
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
 
     /* hsync end is width of sync pulse + 1 */
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
 
     /* hpixels is active pixels */
     wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
 
     /* yendcount is vertical active + vertical blanking */
     yec = var->yres + var->upper_margin + var->lower_margin +
             var->vsync_len;
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
 
     /* libdlo hardcodes vsync start to 0 */
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
 
     /* vsync end is width of vsync pulse */
     wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
 
     /* vpixels is active pixels */
     wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
 
     /* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
     wrptr = dlfb_set_register_16be(wrptr, 0x1B,
             200*1000*1000/var->pixclock);
 
     return wrptr;
 }
 
 /*
  * This takes a standard fbdev screeninfo struct that was fetched or prepared
  * and then generates the appropriate command sequence that then drives the
  * display controller.
  */
 static int dlfb_set_video_mode(struct dlfb_data *dlfb,
                 struct fb_var_screeninfo *var)
 {
     char *buf;
     char *wrptr;
     int retval;
     int writesize;
     struct urb *urb;
 
     if (!atomic_read(&dlfb->usb_active))
         return -EPERM;
 
     urb = dlfb_get_urb(dlfb);
     if (!urb)
         return -ENOMEM;
 
     buf = (char *) urb->transfer_buffer;
 
     /*
     * This first section has to do with setting the base address on the
     * controller * associated with the display. There are 2 base
     * pointers, currently, we only * use the 16 bpp segment.
     */
     wrptr = dlfb_vidreg_lock(buf);
     wrptr = dlfb_set_color_depth(wrptr, 0x00);
     /* set base for 16bpp segment to 0 */
     wrptr = dlfb_set_base16bpp(wrptr, 0);
     /* set base for 8bpp segment to end of fb */
     wrptr = dlfb_set_base8bpp(wrptr, dlfb->info->fix.smem_len);
 
     wrptr = dlfb_set_vid_cmds(wrptr, var);
     wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);
     wrptr = dlfb_vidreg_unlock(wrptr);
 
     writesize = wrptr - buf;
 
     retval = dlfb_submit_urb(dlfb, urb, writesize);
 
     dlfb->blank_mode = FB_BLANK_UNBLANK;
 
     return retval;
 }
 
 static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
     unsigned long start = vma->vm_start;
     unsigned long size = vma->vm_end - vma->vm_start;
     unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
     unsigned long page, pos;
 
     if (info->fbdefio)
         return fb_deferred_io_mmap(info, vma);
 
     if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
         return -EINVAL;
     if (size > info->fix.smem_len)
         return -EINVAL;
     if (offset > info->fix.smem_len - size)
         return -EINVAL;
 
     pos = (unsigned long)info->fix.smem_start + offset;
 
     dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
         pos, size);
 
     while (size > 0) {
         page = vmalloc_to_pfn((void *)pos);
         if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
             return -EAGAIN;
 
         start += PAGE_SIZE;
         pos += PAGE_SIZE;
         if (size > PAGE_SIZE)
             size -= PAGE_SIZE;
         else
             size = 0;
     }
 
     return 0;
 }
 
 /*
  * Trims identical data from front and back of line
  * Sets new front buffer address and width
  * And returns byte count of identical pixels
  * Assumes CPU natural alignment (unsigned long)
  * for back and front buffer ptrs and width
  */
 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 {
     int j, k;
     const unsigned long *back = (const unsigned long *) bback;
     const unsigned long *front = (const unsigned long *) *bfront;
     const int width = *width_bytes / sizeof(unsigned long);
     int identical = width;
     int start = width;
     int end = width;
 
     for (j = 0; j < width; j++) {
         if (back[j] != front[j]) {
             start = j;
             break;
         }
     }
 
     for (k = width - 1; k > j; k--) {
         if (back[k] != front[k]) {
             end = k+1;
             break;
         }
     }
 
     identical = start + (width - end);
     *bfront = (u8 *) &front[start];
     *width_bytes = (end - start) * sizeof(unsigned long);
 
     return identical * sizeof(unsigned long);
 }
 
 /*
  * Render a command stream for an encoded horizontal line segment of pixels.
  *
  * A command buffer holds several commands.
  * It always begins with a fresh command header
  * (the protocol doesn't require this, but we enforce it to allow
  * multiple buffers to be potentially encoded and sent in parallel).
  * A single command encodes one contiguous horizontal line of pixels
  *
  * The function relies on the client to do all allocation, so that
  * rendering can be done directly to output buffers (e.g. USB URBs).
  * The function fills the supplied command buffer, providing information
  * on where it left off, so the client may call in again with additional
  * buffers if the line will take several buffers to complete.
  *
  * A single command can transmit a maximum of 256 pixels,
  * regardless of the compression ratio (protocol design limit).
  * To the hardware, 0 for a size byte means 256
  *
  * Rather than 256 pixel commands which are either rl or raw encoded,
  * the rlx command simply assumes alternating raw and rl spans within one cmd.
  * This has a slightly larger header overhead, but produces more even results.
  * It also processes all data (read and write) in a single pass.
  * Performance benchmarks of common cases show it having just slightly better
  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
  * But for very rl friendly data, will compress not quite as well.
  */
 static void dlfb_compress_hline(
     const uint16_t **pixel_start_ptr,
     const uint16_t *const pixel_end,
     uint32_t *device_address_ptr,
     uint8_t **command_buffer_ptr,
     const uint8_t *const cmd_buffer_end,
     unsigned long back_buffer_offset,
     int *ident_ptr)
 {
     const uint16_t *pixel = *pixel_start_ptr;
     uint32_t dev_addr  = *device_address_ptr;
     uint8_t *cmd = *command_buffer_ptr;
 
     while ((pixel_end > pixel) &&
            (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
         uint8_t *raw_pixels_count_byte = NULL;
         uint8_t *cmd_pixels_count_byte = NULL;
         const uint16_t *raw_pixel_start = NULL;
         const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 
         if (back_buffer_offset &&
             *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
             pixel++;
             dev_addr += BPP;
             (*ident_ptr)++;
             continue;
         }
 
         *cmd++ = 0xAF;
         *cmd++ = 0x6B;
         *cmd++ = dev_addr >> 16;
         *cmd++ = dev_addr >> 8;
         *cmd++ = dev_addr;
 
         cmd_pixels_count_byte = cmd++; /*  we'll know this later */
         cmd_pixel_start = pixel;
 
         raw_pixels_count_byte = cmd++; /*  we'll know this later */
         raw_pixel_start = pixel;
 
         cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
                     (unsigned long)(pixel_end - pixel),
                     (unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
 
         if (back_buffer_offset) {
             /* note: the framebuffer may change under us, so we must test for underflow */
             while (cmd_pixel_end - 1 > pixel &&
                    *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
                 cmd_pixel_end--;
         }
 
         while (pixel < cmd_pixel_end) {
             const uint16_t * const repeating_pixel = pixel;
             u16 pixel_value = *pixel;
 
             put_unaligned_be16(pixel_value, cmd);
             if (back_buffer_offset)
                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
             cmd += 2;
             pixel++;
 
             if (unlikely((pixel < cmd_pixel_end) &&
                      (*pixel == pixel_value))) {
                 /* go back and fill in raw pixel count */
                 *raw_pixels_count_byte = ((repeating_pixel -
                         raw_pixel_start) + 1) & 0xFF;
 
                 do {
                     if (back_buffer_offset)
                         *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
                     pixel++;
                 } while ((pixel < cmd_pixel_end) &&
                      (*pixel == pixel_value));
 
                 /* immediately after raw data is repeat byte */
                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 
                 /* Then start another raw pixel span */
                 raw_pixel_start = pixel;
                 raw_pixels_count_byte = cmd++;
             }
         }
 
         if (pixel > raw_pixel_start) {
             /* finalize last RAW span */
             *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
         } else {
             /* undo unused byte */
             cmd--;
         }
 
         *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
         dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
     }
 
     if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
         /* Fill leftover bytes with no-ops */
         if (cmd_buffer_end > cmd)
             memset(cmd, 0xAF, cmd_buffer_end - cmd);
         cmd = (uint8_t *) cmd_buffer_end;
     }
 
     *command_buffer_ptr = cmd;
     *pixel_start_ptr = pixel;
     *device_address_ptr = dev_addr;
 }
 
 /*
  * There are 3 copies of every pixel: The front buffer that the fbdev
  * client renders to, the actual framebuffer across the USB bus in hardware
  * (that we can only write to, slowly, and can never read), and (optionally)
  * our shadow copy that tracks what's been sent to that hardware buffer.
  */
 static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
                   const char *front, char **urb_buf_ptr,
                   u32 byte_offset, u32 byte_width,
                   int *ident_ptr, int *sent_ptr)
 {
     const u8 *line_start, *line_end, *next_pixel;
     u32 dev_addr = dlfb->base16 + byte_offset;
     struct urb *urb = *urb_ptr;
     u8 *cmd = *urb_buf_ptr;
     u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
     unsigned long back_buffer_offset = 0;
 
     line_start = (u8 *) (front + byte_offset);
     next_pixel = line_start;
     line_end = next_pixel + byte_width;
 
     if (dlfb->backing_buffer) {
         int offset;
         const u8 *back_start = (u8 *) (dlfb->backing_buffer
                         + byte_offset);
 
         back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
 
         *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
             &byte_width);
 
         offset = next_pixel - line_start;
         line_end = next_pixel + byte_width;
         dev_addr += offset;
         back_start += offset;
         line_start += offset;
     }
 
     while (next_pixel < line_end) {
 
         dlfb_compress_hline((const uint16_t **) &next_pixel,
                  (const uint16_t *) line_end, &dev_addr,
             (u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
             ident_ptr);
 
         if (cmd >= cmd_end) {
             int len = cmd - (u8 *) urb->transfer_buffer;
             if (dlfb_submit_urb(dlfb, urb, len))
                 return 1; /* lost pixels is set */
             *sent_ptr += len;
             urb = dlfb_get_urb(dlfb);
             if (!urb)
                 return 1; /* lost_pixels is set */
             *urb_ptr = urb;
             cmd = urb->transfer_buffer;
             cmd_end = &cmd[urb->transfer_buffer_length];
         }
     }
 
     *urb_buf_ptr = cmd;
 
     return 0;
 }
 
 static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 {
     int i, ret;
     char *cmd;
     cycles_t start_cycles, end_cycles;
     int bytes_sent = 0;
     int bytes_identical = 0;
     struct urb *urb;
     int aligned_x;
 
     start_cycles = get_cycles();
 
     mutex_lock(&dlfb->render_mutex);
 
     aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
     width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
     x = aligned_x;
 
     if ((width <= 0) ||
         (x + width > dlfb->info->var.xres) ||
         (y + height > dlfb->info->var.yres)) {
         ret = -EINVAL;
         goto unlock_ret;
     }
 
     if (!atomic_read(&dlfb->usb_active)) {
         ret = 0;
         goto unlock_ret;
     }
 
     urb = dlfb_get_urb(dlfb);
     if (!urb) {
         ret = 0;
         goto unlock_ret;
     }
     cmd = urb->transfer_buffer;
 
     for (i = y; i < y + height ; i++) {
         const int line_offset = dlfb->info->fix.line_length * i;
         const int byte_offset = line_offset + (x * BPP);
 
         if (dlfb_render_hline(dlfb, &urb,
                       (char *) dlfb->info->fix.smem_start,
                       &cmd, byte_offset, width * BPP,
                       &bytes_identical, &bytes_sent))
             goto error;
     }
 
     if (cmd > (char *) urb->transfer_buffer) {
         int len;
         if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
             *cmd++ = 0xAF;
         /* Send partial buffer remaining before exiting */
         len = cmd - (char *) urb->transfer_buffer;
         dlfb_submit_urb(dlfb, urb, len);
         bytes_sent += len;
     } else
         dlfb_urb_completion(urb);
 
 error:
     atomic_add(bytes_sent, &dlfb->bytes_sent);
     atomic_add(bytes_identical, &dlfb->bytes_identical);
     atomic_add(width*height*2, &dlfb->bytes_rendered);
     end_cycles = get_cycles();
     atomic_add(((unsigned int) ((end_cycles - start_cycles)
             >> 10)), /* Kcycles */
            &dlfb->cpu_kcycles_used);
 
     ret = 0;
 
 unlock_ret:
     mutex_unlock(&dlfb->render_mutex);
     return ret;
 }
 
 static void dlfb_init_damage(struct dlfb_data *dlfb)
 {
     dlfb->damage_x = INT_MAX;
     dlfb->damage_x2 = 0;
     dlfb->damage_y = INT_MAX;
     dlfb->damage_y2 = 0;
 }
 
 static void dlfb_damage_work(struct work_struct *w)
 {
     struct dlfb_data *dlfb = container_of(w, struct dlfb_data, damage_work);
     int x, x2, y, y2;
 
     spin_lock_irq(&dlfb->damage_lock);
     x = dlfb->damage_x;
     x2 = dlfb->damage_x2;
     y = dlfb->damage_y;
     y2 = dlfb->damage_y2;
     dlfb_init_damage(dlfb);
     spin_unlock_irq(&dlfb->damage_lock);
 
     if (x < x2 && y < y2)
         dlfb_handle_damage(dlfb, x, y, x2 - x, y2 - y);
 }
 
 static void dlfb_offload_damage(struct dlfb_data *dlfb, int x, int y, int width, int height)
 {
     unsigned long flags;
     int x2 = x + width;
     int y2 = y + height;
 
     if (x >= x2 || y >= y2)
         return;
 
     spin_lock_irqsave(&dlfb->damage_lock, flags);
     dlfb->damage_x = min(x, dlfb->damage_x);
     dlfb->damage_x2 = max(x2, dlfb->damage_x2);
     dlfb->damage_y = min(y, dlfb->damage_y);
     dlfb->damage_y2 = max(y2, dlfb->damage_y2);
     spin_unlock_irqrestore(&dlfb->damage_lock, flags);
 
     schedule_work(&dlfb->damage_work);
 }
 
 /*
  * Path triggered by usermode clients who write to filesystem
  * e.g. cat filename > /dev/fb1
  * Not used by X Windows or text-mode console. But useful for testing.
  * Slow because of extra copy and we must assume all pixels dirty.
  */
 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
               size_t count, loff_t *ppos)
 {
     ssize_t result;
     struct dlfb_data *dlfb = info->par;
     u32 offset = (u32) *ppos;
 
     result = fb_sys_write(info, buf, count, ppos);
 
     if (result > 0) {
         int start = max((int)(offset / info->fix.line_length), 0);
         int lines = min((u32)((result / info->fix.line_length) + 1),
                 (u32)info->var.yres);
 
         dlfb_handle_damage(dlfb, 0, start, info->var.xres,
             lines);
     }
 
     return result;
 }
 
 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 static void dlfb_ops_copyarea(struct fb_info *info,
                 const struct fb_copyarea *area)
 {
 
     struct dlfb_data *dlfb = info->par;
 
     sys_copyarea(info, area);
 
     dlfb_offload_damage(dlfb, area->dx, area->dy,
             area->width, area->height);
 }
 
 static void dlfb_ops_imageblit(struct fb_info *info,
                 const struct fb_image *image)
 {
     struct dlfb_data *dlfb = info->par;
 
     sys_imageblit(info, image);
 
     dlfb_offload_damage(dlfb, image->dx, image->dy,
             image->width, image->height);
 }
 
 static void dlfb_ops_fillrect(struct fb_info *info,
               const struct fb_fillrect *rect)
 {
     struct dlfb_data *dlfb = info->par;
 
     sys_fillrect(info, rect);
 
     dlfb_offload_damage(dlfb, rect->dx, rect->dy, rect->width,
                   rect->height);
 }
 
 /*
  * NOTE: fb_defio.c is holding info->fbdefio.mutex
  *   Touching ANY framebuffer memory that triggers a page fault
  *   in fb_defio will cause a deadlock, when it also tries to
  *   grab the same mutex.
  */
 static void dlfb_dpy_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 {
     struct fb_deferred_io_pageref *pageref;
     struct dlfb_data *dlfb = info->par;
     struct urb *urb;
     char *cmd;
     cycles_t start_cycles, end_cycles;
     int bytes_sent = 0;
     int bytes_identical = 0;
     int bytes_rendered = 0;
 
     mutex_lock(&dlfb->render_mutex);
 
     if (!fb_defio)
         goto unlock_ret;
 
     if (!atomic_read(&dlfb->usb_active))
         goto unlock_ret;
 
     start_cycles = get_cycles();
 
     urb = dlfb_get_urb(dlfb);
     if (!urb)
         goto unlock_ret;
 
     cmd = urb->transfer_buffer;
 
     /* walk the written page list and render each to device */
     list_for_each_entry(pageref, pagereflist, list) {
         if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
                       &cmd, pageref->offset, PAGE_SIZE,
                       &bytes_identical, &bytes_sent))
             goto error;
         bytes_rendered += PAGE_SIZE;
     }
 
     if (cmd > (char *) urb->transfer_buffer) {
         int len;
         if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
             *cmd++ = 0xAF;
         /* Send partial buffer remaining before exiting */
         len = cmd - (char *) urb->transfer_buffer;
         dlfb_submit_urb(dlfb, urb, len);
         bytes_sent += len;
     } else
         dlfb_urb_completion(urb);
 
 error:
     atomic_add(bytes_sent, &dlfb->bytes_sent);
     atomic_add(bytes_identical, &dlfb->bytes_identical);
     atomic_add(bytes_rendered, &dlfb->bytes_rendered);
     end_cycles = get_cycles();
     atomic_add(((unsigned int) ((end_cycles - start_cycles)
             >> 10)), /* Kcycles */
            &dlfb->cpu_kcycles_used);
 unlock_ret:
     mutex_unlock(&dlfb->render_mutex);
 }
 
 static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len)
 {
     int i, ret;
     char *rbuf;
 
     rbuf = kmalloc(2, GFP_KERNEL);
     if (!rbuf)
         return 0;
 
     for (i = 0; i < len; i++) {
         ret = usb_control_msg(dlfb->udev,
                       usb_rcvctrlpipe(dlfb->udev, 0), 0x02,
                       (0x80 | (0x02 << 5)), i << 8, 0xA1,
                       rbuf, 2, USB_CTRL_GET_TIMEOUT);
         if (ret < 2) {
             dev_err(&dlfb->udev->dev,
                 "Read EDID byte %d failed: %d\n", i, ret);
             i--;
             break;
         }
         edid[i] = rbuf[1];
     }
 
     kfree(rbuf);
 
     return i;
 }
 
 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
                 unsigned long arg)
 {
 
     struct dlfb_data *dlfb = info->par;
 
     if (!atomic_read(&dlfb->usb_active))
         return 0;
 
     /* TODO: Update X server to get this from sysfs instead */
     if (cmd == DLFB_IOCTL_RETURN_EDID) {
         void __user *edid = (void __user *)arg;
         if (copy_to_user(edid, dlfb->edid, dlfb->edid_size))
             return -EFAULT;
         return 0;
     }
 
     /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
     if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
         struct dloarea area;
 
         if (copy_from_user(&area, (void __user *)arg,
                   sizeof(struct dloarea)))
             return -EFAULT;
 
         /*
          * If we have a damage-aware client, turn fb_defio "off"
          * To avoid perf imact of unnecessary page fault handling.
          * Done by resetting the delay for this fb_info to a very
          * long period. Pages will become writable and stay that way.
          * Reset to normal value when all clients have closed this fb.
          */
         if (info->fbdefio)
             info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 
         if (area.x < 0)
             area.x = 0;
 
         if (area.x > info->var.xres)
             area.x = info->var.xres;
 
         if (area.y < 0)
             area.y = 0;
 
         if (area.y > info->var.yres)
             area.y = info->var.yres;
 
         dlfb_handle_damage(dlfb, area.x, area.y, area.w, area.h);
     }
 
     return 0;
 }
 
 /* taken from vesafb */
 static int
 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
            unsigned blue, unsigned transp, struct fb_info *info)
 {
     int err = 0;
 
     if (regno >= info->cmap.len)
         return 1;
 
     if (regno < 16) {
         if (info->var.red.offset == 10) {
             /* 1:5:5:5 */
             ((u32 *) (info->pseudo_palette))[regno] =
                 ((red & 0xf800) >> 1) |
                 ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
         } else {
             /* 0:5:6:5 */
             ((u32 *) (info->pseudo_palette))[regno] =
                 ((red & 0xf800)) |
                 ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
         }
     }
 
     return err;
 }
 
 /*
  * It's common for several clients to have framebuffer open simultaneously.
  * e.g. both fbcon and X. Makes things interesting.
  * Assumes caller is holding info->lock (for open and release at least)
  */
 static int dlfb_ops_open(struct fb_info *info, int user)
 {
     struct dlfb_data *dlfb = info->par;
 
     /*
      * fbcon aggressively connects to first framebuffer it finds,
      * preventing other clients (X) from working properly. Usually
      * not what the user wants. Fail by default with option to enable.
      */
     if ((user == 0) && (!console))
         return -EBUSY;
 
     /* If the USB device is gone, we don't accept new opens */
     if (dlfb->virtualized)
         return -ENODEV;
 
     dlfb->fb_count++;
 
     if (fb_defio && (info->fbdefio == NULL)) {
         /* enable defio at last moment if not disabled by client */
 
         struct fb_deferred_io *fbdefio;
 
         fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 
         if (fbdefio) {
             fbdefio->delay = DL_DEFIO_WRITE_DELAY;
             fbdefio->sort_pagereflist = true;
             fbdefio->deferred_io = dlfb_dpy_deferred_io;
         }
 
         info->fbdefio = fbdefio;
         fb_deferred_io_init(info);
     }
 
     dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
         user, info, dlfb->fb_count);
 
     return 0;
 }
 
 static void dlfb_ops_destroy(struct fb_info *info)
 {
     struct dlfb_data *dlfb = info->par;
 
     cancel_work_sync(&dlfb->damage_work);
 
     mutex_destroy(&dlfb->render_mutex);
 
     if (info->cmap.len != 0)
         fb_dealloc_cmap(&info->cmap);
     if (info->monspecs.modedb)
         fb_destroy_modedb(info->monspecs.modedb);
     vfree(info->screen_base);
 
     fb_destroy_modelist(&info->modelist);
 
     while (!list_empty(&dlfb->deferred_free)) {
         struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
         list_del(&d->list);
         vfree(d->mem);
         kfree(d);
     }
     vfree(dlfb->backing_buffer);
     kfree(dlfb->edid);
     dlfb_free_urb_list(dlfb);
     usb_put_dev(dlfb->udev);
     kfree(dlfb);
 
     /* Assume info structure is freed after this point */
     framebuffer_release(info);
 }
 
 /*
  * Assumes caller is holding info->lock mutex (for open and release at least)
  */
 static int dlfb_ops_release(struct fb_info *info, int user)
 {
     struct dlfb_data *dlfb = info->par;
 
     dlfb->fb_count--;
 
     if ((dlfb->fb_count == 0) && (info->fbdefio)) {
         fb_deferred_io_cleanup(info);
         kfree(info->fbdefio);
         info->fbdefio = NULL;
     }
 
     dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
 
     return 0;
 }
 
 /*
  * Check whether a video mode is supported by the DisplayLink chip
  * We start from monitor's modes, so don't need to filter that here
  */
 static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
 {
     if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
         return 0;
 
     return 1;
 }
 
 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
 {
     const struct fb_bitfield red = { 11, 5, 0 };
     const struct fb_bitfield green = { 5, 6, 0 };
     const struct fb_bitfield blue = { 0, 5, 0 };
 
     var->bits_per_pixel = 16;
     var->red = red;
     var->green = green;
     var->blue = blue;
 }
 
 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
                 struct fb_info *info)
 {
     struct fb_videomode mode;
     struct dlfb_data *dlfb = info->par;
 
     /* set device-specific elements of var unrelated to mode */
     dlfb_var_color_format(var);
 
     fb_var_to_videomode(&mode, var);
 
     if (!dlfb_is_valid_mode(&mode, dlfb))
         return -EINVAL;
 
     return 0;
 }
 
 static int dlfb_ops_set_par(struct fb_info *info)
 {
     struct dlfb_data *dlfb = info->par;
     int result;
     u16 *pix_framebuffer;
     int i;
     struct fb_var_screeninfo fvs;
     u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
 
     /* clear the activate field because it causes spurious miscompares */
     fvs = info->var;
     fvs.activate = 0;
     fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
 
     if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
         return 0;
 
     result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
     if (result)
         return result;
 
     result = dlfb_set_video_mode(dlfb, &info->var);
 
     if (result)
         return result;
 
     dlfb->current_mode = fvs;
     info->fix.line_length = line_length;
 
     if (dlfb->fb_count == 0) {
 
         /* paint greenscreen */
 
         pix_framebuffer = (u16 *) info->screen_base;
         for (i = 0; i < info->fix.smem_len / 2; i++)
             pix_framebuffer[i] = 0x37e6;
     }
 
     dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres);
 
     return 0;
 }
 
 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
 static char *dlfb_dummy_render(char *buf)
 {
     *buf++ = 0xAF;
     *buf++ = 0x6A; /* copy */
     *buf++ = 0x00; /* from address*/
     *buf++ = 0x00;
     *buf++ = 0x00;
     *buf++ = 0x01; /* one pixel */
     *buf++ = 0x00; /* to address */
     *buf++ = 0x00;
     *buf++ = 0x00;
     return buf;
 }
 
 /*
  * In order to come back from full DPMS off, we need to set the mode again
  */
 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
 {
     struct dlfb_data *dlfb = info->par;
     char *bufptr;
     struct urb *urb;
 
     dev_dbg(info->dev, "blank, mode %d --> %d\n",
         dlfb->blank_mode, blank_mode);
 
     if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
         (blank_mode != FB_BLANK_POWERDOWN)) {
 
         /* returning from powerdown requires a fresh modeset */
         dlfb_set_video_mode(dlfb, &info->var);
     }
 
     urb = dlfb_get_urb(dlfb);
     if (!urb)
         return 0;
 
     bufptr = (char *) urb->transfer_buffer;
     bufptr = dlfb_vidreg_lock(bufptr);
     bufptr = dlfb_blanking(bufptr, blank_mode);
     bufptr = dlfb_vidreg_unlock(bufptr);
 
     /* seems like a render op is needed to have blank change take effect */
     bufptr = dlfb_dummy_render(bufptr);
 
     dlfb_submit_urb(dlfb, urb, bufptr -
             (char *) urb->transfer_buffer);
 
     dlfb->blank_mode = blank_mode;
 
     return 0;
 }
 
 static const struct fb_ops dlfb_ops = {
     .owner = THIS_MODULE,
     .fb_read = fb_sys_read,
     .fb_write = dlfb_ops_write,
     .fb_setcolreg = dlfb_ops_setcolreg,
     .fb_fillrect = dlfb_ops_fillrect,
     .fb_copyarea = dlfb_ops_copyarea,
     .fb_imageblit = dlfb_ops_imageblit,
     .fb_mmap = dlfb_ops_mmap,
     .fb_ioctl = dlfb_ops_ioctl,
     .fb_open = dlfb_ops_open,
     .fb_release = dlfb_ops_release,
     .fb_blank = dlfb_ops_blank,
     .fb_check_var = dlfb_ops_check_var,
     .fb_set_par = dlfb_ops_set_par,
     .fb_destroy = dlfb_ops_destroy,
 };
 
 
 static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
 {
     struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
     if (!d)
         return;
     d->mem = mem;
     list_add(&d->list, &dlfb->deferred_free);
 }
 
 /*
  * Assumes &info->lock held by caller
  * Assumes no active clients have framebuffer open
  */
 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
 {
     u32 old_len = info->fix.smem_len;
     const void *old_fb = (const void __force *)info->screen_base;
     unsigned char *new_fb;
     unsigned char *new_back = NULL;
 
     new_len = PAGE_ALIGN(new_len);
 
     if (new_len > old_len) {
         /*
          * Alloc system memory for virtual framebuffer
          */
         new_fb = vmalloc(new_len);
         if (!new_fb) {
             dev_err(info->dev, "Virtual framebuffer alloc failed\n");
             return -ENOMEM;
         }
         memset(new_fb, 0xff, new_len);
 
         if (info->screen_base) {
             memcpy(new_fb, old_fb, old_len);
             dlfb_deferred_vfree(dlfb, (void __force *)info->screen_base);
         }
 
         info->screen_base = (char __iomem *)new_fb;
         info->fix.smem_len = new_len;
         info->fix.smem_start = (unsigned long) new_fb;
         info->flags = udlfb_info_flags;
 
         /*
          * Second framebuffer copy to mirror the framebuffer state
          * on the physical USB device. We can function without this.
          * But with imperfect damage info we may send pixels over USB
          * that were, in fact, unchanged - wasting limited USB bandwidth
          */
         if (shadow)
             new_back = vzalloc(new_len);
         if (!new_back)
             dev_info(info->dev,
                  "No shadow/backing buffer allocated\n");
         else {
             dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
             dlfb->backing_buffer = new_back;
         }
     }
     return 0;
 }
 
 /*
  * 1) Get EDID from hw, or use sw default
  * 2) Parse into various fb_info structs
  * 3) Allocate virtual framebuffer memory to back highest res mode
  *
  * Parses EDID into three places used by various parts of fbdev:
  * fb_var_screeninfo contains the timing of the monitor's preferred mode
  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
  * fb_info.modelist is a linked list of all monitor & VESA modes which work
  *
  * If EDID is not readable/valid, then modelist is all VESA modes,
  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
  * Returns 0 if successful
  */
 static int dlfb_setup_modes(struct dlfb_data *dlfb,
                struct fb_info *info,
                char *default_edid, size_t default_edid_size)
 {
     char *edid;
     int i, result = 0, tries = 3;
     struct device *dev = info->device;
     struct fb_videomode *mode;
     const struct fb_videomode *default_vmode = NULL;
 
     if (info->dev) {
         /* only use mutex if info has been registered */
         mutex_lock(&info->lock);
         /* parent device is used otherwise */
         dev = info->dev;
     }
 
     edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
     if (!edid) {
         result = -ENOMEM;
         goto error;
     }
 
     fb_destroy_modelist(&info->modelist);
     memset(&info->monspecs, 0, sizeof(info->monspecs));
 
     /*
      * Try to (re)read EDID from hardware first
      * EDID data may return, but not parse as valid
      * Try again a few times, in case of e.g. analog cable noise
      */
     while (tries--) {
 
         i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
 
         if (i >= EDID_LENGTH)
             fb_edid_to_monspecs(edid, &info->monspecs);
 
         if (info->monspecs.modedb_len > 0) {
             dlfb->edid = edid;
             dlfb->edid_size = i;
             break;
         }
     }
 
     /* If that fails, use a previously returned EDID if available */
     if (info->monspecs.modedb_len == 0) {
         dev_err(dev, "Unable to get valid EDID from device/display\n");
 
         if (dlfb->edid) {
             fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
             if (info->monspecs.modedb_len > 0)
                 dev_err(dev, "Using previously queried EDID\n");
         }
     }
 
     /* If that fails, use the default EDID we were handed */
     if (info->monspecs.modedb_len == 0) {
         if (default_edid_size >= EDID_LENGTH) {
             fb_edid_to_monspecs(default_edid, &info->monspecs);
             if (info->monspecs.modedb_len > 0) {
                 memcpy(edid, default_edid, default_edid_size);
                 dlfb->edid = edid;
                 dlfb->edid_size = default_edid_size;
                 dev_err(dev, "Using default/backup EDID\n");
             }
         }
     }
 
     /* If we've got modes, let's pick a best default mode */
     if (info->monspecs.modedb_len > 0) {
 
         for (i = 0; i < info->monspecs.modedb_len; i++) {
             mode = &info->monspecs.modedb[i];
             if (dlfb_is_valid_mode(mode, dlfb)) {
                 fb_add_videomode(mode, &info->modelist);
             } else {
                 dev_dbg(dev, "Specified mode %dx%d too big\n",
                     mode->xres, mode->yres);
                 if (i == 0)
                     /* if we've removed top/best mode */
                     info->monspecs.misc
                         &= ~FB_MISC_1ST_DETAIL;
             }
         }
 
         default_vmode = fb_find_best_display(&info->monspecs,
                              &info->modelist);
     }
 
     /* If everything else has failed, fall back to safe default mode */
     if (default_vmode == NULL) {
 
         struct fb_videomode fb_vmode = {0};
 
         /*
          * Add the standard VESA modes to our modelist
          * Since we don't have EDID, there may be modes that
          * overspec monitor and/or are incorrect aspect ratio, etc.
          * But at least the user has a chance to choose
          */
         for (i = 0; i < VESA_MODEDB_SIZE; i++) {
             mode = (struct fb_videomode *)&vesa_modes[i];
             if (dlfb_is_valid_mode(mode, dlfb))
                 fb_add_videomode(mode, &info->modelist);
             else
                 dev_dbg(dev, "VESA mode %dx%d too big\n",
                     mode->xres, mode->yres);
         }
 
         /*
          * default to resolution safe for projectors
          * (since they are most common case without EDID)
          */
         fb_vmode.xres = 800;
         fb_vmode.yres = 600;
         fb_vmode.refresh = 60;
         default_vmode = fb_find_nearest_mode(&fb_vmode,
                              &info->modelist);
     }
 
     /* If we have good mode and no active clients*/
     if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
 
         fb_videomode_to_var(&info->var, default_vmode);
         dlfb_var_color_format(&info->var);
 
         /*
          * with mode size info, we can now alloc our framebuffer.
          */
         memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
     } else
         result = -EINVAL;
 
 error:
     if (edid && (dlfb->edid != edid))
         kfree(edid);
 
     if (info->dev)
         mutex_unlock(&info->lock);
 
     return result;
 }
 
 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
                    struct device_attribute *a, char *buf) {
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
     return sysfs_emit(buf, "%u\n",
             atomic_read(&dlfb->bytes_rendered));
 }
 
 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
                    struct device_attribute *a, char *buf) {
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
     return sysfs_emit(buf, "%u\n",
             atomic_read(&dlfb->bytes_identical));
 }
 
 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
                    struct device_attribute *a, char *buf) {
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
     return sysfs_emit(buf, "%u\n",
             atomic_read(&dlfb->bytes_sent));
 }
 
 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
                    struct device_attribute *a, char *buf) {
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
     return sysfs_emit(buf, "%u\n",
             atomic_read(&dlfb->cpu_kcycles_used));
 }
 
 static ssize_t edid_show(
             struct file *filp,
             struct kobject *kobj, struct bin_attribute *a,
              char *buf, loff_t off, size_t count) {
     struct device *fbdev = kobj_to_dev(kobj);
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
 
     if (dlfb->edid == NULL)
         return 0;
 
     if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
         return 0;
 
     if (off + count > dlfb->edid_size)
         count = dlfb->edid_size - off;
 
     memcpy(buf, dlfb->edid, count);
 
     return count;
 }
 
 static ssize_t edid_store(
             struct file *filp,
             struct kobject *kobj, struct bin_attribute *a,
             char *src, loff_t src_off, size_t src_size) {
     struct device *fbdev = kobj_to_dev(kobj);
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
     int ret;
 
     /* We only support write of entire EDID at once, no offset*/
     if ((src_size != EDID_LENGTH) || (src_off != 0))
         return -EINVAL;
 
     ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
     if (ret)
         return ret;
 
     if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
         return -EINVAL;
 
     ret = dlfb_ops_set_par(fb_info);
     if (ret)
         return ret;
 
     return src_size;
 }
 
 static ssize_t metrics_reset_store(struct device *fbdev,
                struct device_attribute *attr,
                const char *buf, size_t count)
 {
     struct fb_info *fb_info = dev_get_drvdata(fbdev);
     struct dlfb_data *dlfb = fb_info->par;
 
     atomic_set(&dlfb->bytes_rendered, 0);
     atomic_set(&dlfb->bytes_identical, 0);
     atomic_set(&dlfb->bytes_sent, 0);
     atomic_set(&dlfb->cpu_kcycles_used, 0);
 
     return count;
 }
 
 static const struct bin_attribute edid_attr = {
     .attr.name = "edid",
     .attr.mode = 0666,
     .size = EDID_LENGTH,
     .read = edid_show,
     .write = edid_store
 };
 
 static const struct device_attribute fb_device_attrs[] = {
     __ATTR_RO(metrics_bytes_rendered),
     __ATTR_RO(metrics_bytes_identical),
     __ATTR_RO(metrics_bytes_sent),
     __ATTR_RO(metrics_cpu_kcycles_used),
     __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
 };
 
 /*
  * This is necessary before we can communicate with the display controller.
  */
 static int dlfb_select_std_channel(struct dlfb_data *dlfb)
 {
     int ret;
     void *buf;
     static const u8 set_def_chn[] = {
                 0x57, 0xCD, 0xDC, 0xA7,
                 0x1C, 0x88, 0x5E, 0x15,
                 0x60, 0xFE, 0xC6, 0x97,
                 0x16, 0x3D, 0x47, 0xF2  };
 
     buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
 
     if (!buf)
         return -ENOMEM;
 
     ret = usb_control_msg(dlfb->udev, usb_sndctrlpipe(dlfb->udev, 0),
             NR_USB_REQUEST_CHANNEL,
             (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
             buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
 
     kfree(buf);
 
     return ret;
 }
 
 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
                     struct usb_interface *intf)
 {
     char *desc;
     char *buf;
     char *desc_end;
     int total_len;
 
     buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
     if (!buf)
         return false;
     desc = buf;
 
     total_len = usb_get_descriptor(interface_to_usbdev(intf),
                     0x5f, /* vendor specific */
                     0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
 
     /* if not found, look in configuration descriptor */
     if (total_len < 0) {
         if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
             0x5f, &desc))
             total_len = (int) desc[0];
     }
 
     if (total_len > 5) {
         dev_info(&intf->dev,
              "vendor descriptor length: %d data: %11ph\n",
              total_len, desc);
 
         if ((desc[0] != total_len) || /* descriptor length */
             (desc[1] != 0x5f) ||   /* vendor descriptor type */
             (desc[2] != 0x01) ||   /* version (2 bytes) */
             (desc[3] != 0x00) ||
             (desc[4] != total_len - 2)) /* length after type */
             goto unrecognized;
 
         desc_end = desc + total_len;
         desc += 5; /* the fixed header we've already parsed */
 
         while (desc < desc_end) {
             u8 length;
             u16 key;
 
             key = *desc++;
             key |= (u16)*desc++ << 8;
             length = *desc++;
 
             switch (key) {
             case 0x0200: { /* max_area */
                 u32 max_area = *desc++;
                 max_area |= (u32)*desc++ << 8;
                 max_area |= (u32)*desc++ << 16;
                 max_area |= (u32)*desc++ << 24;
                 dev_warn(&intf->dev,
                      "DL chip limited to %d pixel modes\n",
                      max_area);
                 dlfb->sku_pixel_limit = max_area;
                 break;
             }
             default:
                 break;
             }
             desc += length;
         }
     } else {
         dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
              total_len);
     }
 
     goto success;
 
 unrecognized:
     /* allow udlfb to load for now even if firmware unrecognized */
     dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
 
 success:
     kfree(buf);
     return true;
 }
 
 static int dlfb_usb_probe(struct usb_interface *intf,
               const struct usb_device_id *id)
 {
     int i;
     const struct device_attribute *attr;
     struct dlfb_data *dlfb;
     struct fb_info *info;
     int retval;
     struct usb_device *usbdev = interface_to_usbdev(intf);
     struct usb_endpoint_descriptor *out;
 
     /* usb initialization */
     dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
     if (!dlfb) {
         dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
         return -ENOMEM;
     }
 
     INIT_LIST_HEAD(&dlfb->deferred_free);
 
     dlfb->udev = usb_get_dev(usbdev);
     usb_set_intfdata(intf, dlfb);
 
     retval = usb_find_common_endpoints(intf->cur_altsetting, NULL, &out, NULL, NULL);
     if (retval) {
         dev_err(&intf->dev, "Device should have at lease 1 bulk endpoint!\n");
         goto error;
     }
 
     dev_dbg(&intf->dev, "console enable=%d\n", console);
     dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
     dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
 
     dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
 
     if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
         dev_err(&intf->dev,
             "firmware not recognized, incompatible device?\n");
         retval = -ENODEV;
         goto error;
     }
 
     if (pixel_limit) {
         dev_warn(&intf->dev,
              "DL chip limit of %d overridden to %d\n",
              dlfb->sku_pixel_limit, pixel_limit);
         dlfb->sku_pixel_limit = pixel_limit;
     }
 
 
     /* allocates framebuffer driver structure, not framebuffer memory */
     info = framebuffer_alloc(0, &dlfb->udev->dev);
     if (!info) {
         retval = -ENOMEM;
         goto error;
     }
 
     dlfb->info = info;
     info->par = dlfb;
     info->pseudo_palette = dlfb->pseudo_palette;
     dlfb->ops = dlfb_ops;
     info->fbops = &dlfb->ops;
 
     mutex_init(&dlfb->render_mutex);
     dlfb_init_damage(dlfb);
     spin_lock_init(&dlfb->damage_lock);
     INIT_WORK(&dlfb->damage_work, dlfb_damage_work);
 
     INIT_LIST_HEAD(&info->modelist);
 
     if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
         retval = -ENOMEM;
         dev_err(&intf->dev, "unable to allocate urb list\n");
         goto error;
     }
 
     /* We don't register a new USB class. Our client interface is dlfbev */
 
     retval = fb_alloc_cmap(&info->cmap, 256, 0);
     if (retval < 0) {
         dev_err(info->device, "cmap allocation failed: %d\n", retval);
         goto error;
     }
 
     retval = dlfb_setup_modes(dlfb, info, NULL, 0);
     if (retval != 0) {
         dev_err(info->device,
             "unable to find common mode for display and adapter\n");
         goto error;
     }
 
     /* ready to begin using device */
 
     atomic_set(&dlfb->usb_active, 1);
     dlfb_select_std_channel(dlfb);
 
     dlfb_ops_check_var(&info->var, info);
     retval = dlfb_ops_set_par(info);
     if (retval)
         goto error;
 
     retval = register_framebuffer(info);
     if (retval < 0) {
         dev_err(info->device, "unable to register framebuffer: %d\n",
             retval);
         goto error;
     }
 
     for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
         attr = &fb_device_attrs[i];
         retval = device_create_file(info->dev, attr);
         if (retval)
             dev_warn(info->device,
                  "failed to create '%s' attribute: %d\n",
                  attr->attr.name, retval);
     }
 
     retval = device_create_bin_file(info->dev, &edid_attr);
     if (retval)
         dev_warn(info->device, "failed to create '%s' attribute: %d\n",
              edid_attr.attr.name, retval);
 
     dev_info(info->device,
          "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
          dev_name(info->dev), info->var.xres, info->var.yres,
          ((dlfb->backing_buffer) ?
          info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
     return 0;
 
 error:
     if (dlfb->info) {
         dlfb_ops_destroy(dlfb->info);
     } else {
         usb_put_dev(dlfb->udev);
         kfree(dlfb);
     }
     return retval;
 }
 
 static void dlfb_usb_disconnect(struct usb_interface *intf)
 {
     struct dlfb_data *dlfb;
     struct fb_info *info;
     int i;
 
     dlfb = usb_get_intfdata(intf);
     info = dlfb->info;
 
     dev_dbg(&intf->dev, "USB disconnect starting\n");
 
     /* we virtualize until all fb clients release. Then we free */
     dlfb->virtualized = true;
 
     /* When non-active we'll update virtual framebuffer, but no new urbs */
     atomic_set(&dlfb->usb_active, 0);
 
     /* this function will wait for all in-flight urbs to complete */
     dlfb_free_urb_list(dlfb);
 
     /* remove udlfb's sysfs interfaces */
     for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
         device_remove_file(info->dev, &fb_device_attrs[i]);
     device_remove_bin_file(info->dev, &edid_attr);
 
     unregister_framebuffer(info);
 }
 
 static struct usb_driver dlfb_driver = {
     .name = "udlfb",
     .probe = dlfb_usb_probe,
     .disconnect = dlfb_usb_disconnect,
     .id_table = id_table,
 };
 
 module_usb_driver(dlfb_driver);
 
 static void dlfb_urb_completion(struct urb *urb)
 {
     struct urb_node *unode = urb->context;
     struct dlfb_data *dlfb = unode->dlfb;
     unsigned long flags;
 
     switch (urb->status) {
     case 0:
         /* success */
         break;
     case -ECONNRESET:
     case -ENOENT:
     case -ESHUTDOWN:
         /* sync/async unlink faults aren't errors */
         break;
     default:
         dev_err(&dlfb->udev->dev,
             "%s - nonzero write bulk status received: %d\n",
             __func__, urb->status);
         atomic_set(&dlfb->lost_pixels, 1);
         break;
     }
 
     urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
 
     spin_lock_irqsave(&dlfb->urbs.lock, flags);
     list_add_tail(&unode->entry, &dlfb->urbs.list);
     dlfb->urbs.available++;
     spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
 
     up(&dlfb->urbs.limit_sem);
 }
 
 static void dlfb_free_urb_list(struct dlfb_data *dlfb)
 {
     int count = dlfb->urbs.count;
     struct list_head *node;
     struct urb_node *unode;
     struct urb *urb;
 
     /* keep waiting and freeing, until we've got 'em all */
     while (count--) {
         down(&dlfb->urbs.limit_sem);
 
         spin_lock_irq(&dlfb->urbs.lock);
 
         node = dlfb->urbs.list.next; /* have reserved one with sem */
         list_del_init(node);
 
         spin_unlock_irq(&dlfb->urbs.lock);
 
         unode = list_entry(node, struct urb_node, entry);
         urb = unode->urb;
 
         /* Free each separately allocated piece */
         usb_free_coherent(urb->dev, dlfb->urbs.size,
                   urb->transfer_buffer, urb->transfer_dma);
         usb_free_urb(urb);
         kfree(node);
     }
 
     dlfb->urbs.count = 0;
 }
 
 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
 {
     struct urb *urb;
     struct urb_node *unode;
     char *buf;
     size_t wanted_size = count * size;
 
     spin_lock_init(&dlfb->urbs.lock);
 
 retry:
     dlfb->urbs.size = size;
     INIT_LIST_HEAD(&dlfb->urbs.list);
 
     sema_init(&dlfb->urbs.limit_sem, 0);
     dlfb->urbs.count = 0;
     dlfb->urbs.available = 0;
 
     while (dlfb->urbs.count * size < wanted_size) {
         unode = kzalloc(sizeof(*unode), GFP_KERNEL);
         if (!unode)
             break;
         unode->dlfb = dlfb;
 
         urb = usb_alloc_urb(0, GFP_KERNEL);
         if (!urb) {
             kfree(unode);
             break;
         }
         unode->urb = urb;
 
         buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
                      &urb->transfer_dma);
         if (!buf) {
             kfree(unode);
             usb_free_urb(urb);
             if (size > PAGE_SIZE) {
                 size /= 2;
                 dlfb_free_urb_list(dlfb);
                 goto retry;
             }
             break;
         }
 
         /* urb->transfer_buffer_length set to actual before submit */
         usb_fill_bulk_urb(urb, dlfb->udev, usb_sndbulkpipe(dlfb->udev, 1),
             buf, size, dlfb_urb_completion, unode);
         urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 
         list_add_tail(&unode->entry, &dlfb->urbs.list);
 
         up(&dlfb->urbs.limit_sem);
         dlfb->urbs.count++;
         dlfb->urbs.available++;
     }
 
     return dlfb->urbs.count;
 }
 
 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
 {
     int ret;
     struct list_head *entry;
     struct urb_node *unode;
 
     /* Wait for an in-flight buffer to complete and get re-queued */
     ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
     if (ret) {
         atomic_set(&dlfb->lost_pixels, 1);
         dev_warn(&dlfb->udev->dev,
              "wait for urb interrupted: %d available: %d\n",
              ret, dlfb->urbs.available);
         return NULL;
     }
 
     spin_lock_irq(&dlfb->urbs.lock);
 
     BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
     entry = dlfb->urbs.list.next;
     list_del_init(entry);
     dlfb->urbs.available--;
 
     spin_unlock_irq(&dlfb->urbs.lock);
 
     unode = list_entry(entry, struct urb_node, entry);
     return unode->urb;
 }
 
 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
 {
     int ret;
 
     BUG_ON(len > dlfb->urbs.size);
 
     urb->transfer_buffer_length = len; /* set to actual payload len */
     ret = usb_submit_urb(urb, GFP_KERNEL);
     if (ret) {
         dlfb_urb_completion(urb); /* because no one else will */
         atomic_set(&dlfb->lost_pixels, 1);
         dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
     }
     return ret;
 }
 
 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
 
 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
 
 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
 
 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
 
 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
           "Jaya Kumar <jayakumar.lkml@gmail.com>, "
           "Bernie Thompson <bernie@plugable.com>");
 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
 MODULE_LICENSE("GPL");
 

This page was automatically generated by the 2.1.0 LXR engine. The LXR team