drivers/video/udlfb.c

   1 /*
   2  * udlfb.c -- Framebuffer driver for DisplayLink USB controller
   3  *
   4  * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
   5  * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
   6  * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License v2. See the file COPYING in the main directory of this archive for
  10  * more details.
  11  *
  12  * Layout is based on skeletonfb by James Simmons and Geert Uytterhoeven,
  13  * usb-skeleton by GregKH.
  14  *
  15  * Device-specific portions based on information from Displaylink, with work
  16  * from Florian Echtler, Henrik Bjerregaard Pedersen, and others.
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/init.h>
  24 #include <linux/usb.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/mm.h>
  27 #include <linux/fb.h>
  28 #include <linux/vmalloc.h>
  29 #include <linux/slab.h>
  30 #include <linux/prefetch.h>
  31 #include <linux/delay.h>
  32 #include <video/udlfb.h>
  33 #include "edid.h"
  34
  35 static struct fb_fix_screeninfo dlfb_fix = {
  36         .id =           "udlfb",
  37         .type =         FB_TYPE_PACKED_PIXELS,
  38         .visual =       FB_VISUAL_TRUECOLOR,
  39         .xpanstep =     0,
  40         .ypanstep =     0,
  41         .ywrapstep =    0,
  42         .accel =        FB_ACCEL_NONE,
  43 };
  44
  45 static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
  46                 FBINFO_VIRTFB |
  47                 FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
  48                 FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
  49
  50 /*
  51  * There are many DisplayLink-based graphics products, all with unique PIDs.
  52  * So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
  53  * We also require a match on SubClass (0x00) and Protocol (0x00),
  54  * which is compatible with all known USB 2.0 era graphics chips and firmware,
  55  * but allows DisplayLink to increment those for any future incompatible chips
  56  */
  57 static struct usb_device_id id_table[] = {
  58         {.idVendor = 0x17e9,
  59          .bInterfaceClass = 0xff,
  60          .bInterfaceSubClass = 0x00,
  61          .bInterfaceProtocol = 0x00,
  62          .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
  63                 USB_DEVICE_ID_MATCH_INT_CLASS |
  64                 USB_DEVICE_ID_MATCH_INT_SUBCLASS |
  65                 USB_DEVICE_ID_MATCH_INT_PROTOCOL,
  66         },
  67         {},
  68 };
  69 MODULE_DEVICE_TABLE(usb, id_table);
  70
  71 /* module options */
  72 static bool console = 1; /* Allow fbcon to open framebuffer */
  73 static bool fb_defio = 1;  /* Detect mmap writes using page faults */
  74 static bool shadow = 1; /* Optionally disable shadow framebuffer */
  75 static int pixel_limit; /* Optionally force a pixel resolution limit */
  76
  77 /* dlfb keeps a list of urbs for efficient bulk transfers */
  78 static void dlfb_urb_completion(struct urb *urb);
  79 static struct urb *dlfb_get_urb(struct dlfb_data *dev);
  80 static int dlfb_submit_urb(struct dlfb_data *dev, struct urb * urb, size_t len);
  81 static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size);
  82 static void dlfb_free_urb_list(struct dlfb_data *dev);
  83
  84 /*
  85  * All DisplayLink bulk operations start with 0xAF, followed by specific code
  86  * All operations are written to buffers which then later get sent to device
  87  */
  88 static char *dlfb_set_register(char *buf, u8 reg, u8 val)
  89 {
  90         *buf++ = 0xAF;
  91         *buf++ = 0x20;
  92         *buf++ = reg;
  93         *buf++ = val;
  94         return buf;
  95 }
  96
  97 static char *dlfb_vidreg_lock(char *buf)
  98 {
  99         return dlfb_set_register(buf, 0xFF, 0x00);
 100 }
 101
 102 static char *dlfb_vidreg_unlock(char *buf)
 103 {
 104         return dlfb_set_register(buf, 0xFF, 0xFF);
 105 }
 106
 107 /*
 108  * Map FB_BLANK_* to DisplayLink register
 109  * DLReg FB_BLANK_*
 110  * ----- -----------------------------
 111  *  0x00 FB_BLANK_UNBLANK (0)
 112  *  0x01 FB_BLANK (1)
 113  *  0x03 FB_BLANK_VSYNC_SUSPEND (2)
 114  *  0x05 FB_BLANK_HSYNC_SUSPEND (3)
 115  *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back
 116  */
 117 static char *dlfb_blanking(char *buf, int fb_blank)
 118 {
 119         u8 reg;
 120
 121         switch (fb_blank) {
 122         case FB_BLANK_POWERDOWN:
 123                 reg = 0x07;
 124                 break;
 125         case FB_BLANK_HSYNC_SUSPEND:
 126                 reg = 0x05;
 127                 break;
 128         case FB_BLANK_VSYNC_SUSPEND:
 129                 reg = 0x03;
 130                 break;
 131         case FB_BLANK_NORMAL:
 132                 reg = 0x01;
 133                 break;
 134         default:
 135                 reg = 0x00;
 136         }
 137
 138         buf = dlfb_set_register(buf, 0x1F, reg);
 139
 140         return buf;
 141 }
 142
 143 static char *dlfb_set_color_depth(char *buf, u8 selection)
 144 {
 145         return dlfb_set_register(buf, 0x00, selection);
 146 }
 147
 148 static char *dlfb_set_base16bpp(char *wrptr, u32 base)
 149 {
 150         /* the base pointer is 16 bits wide, 0x20 is hi byte. */
 151         wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
 152         wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
 153         return dlfb_set_register(wrptr, 0x22, base);
 154 }
 155
 156 /*
 157  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
 158  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
 159  */
 160 static char *dlfb_set_base8bpp(char *wrptr, u32 base)
 161 {
 162         wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
 163         wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
 164         return dlfb_set_register(wrptr, 0x28, base);
 165 }
 166
 167 static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
 168 {
 169         wrptr = dlfb_set_register(wrptr, reg, value >> 8);
 170         return dlfb_set_register(wrptr, reg+1, value);
 171 }
 172
 173 /*
 174  * This is kind of weird because the controller takes some
 175  * register values in a different byte order than other registers.
 176  */
 177 static char *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
 178 {
 179         wrptr = dlfb_set_register(wrptr, reg, value);
 180         return dlfb_set_register(wrptr, reg+1, value >> 8);
 181 }
 182
 183 /*
 184  * LFSR is linear feedback shift register. The reason we have this is
 185  * because the display controller needs to minimize the clock depth of
 186  * various counters used in the display path. So this code reverses the
 187  * provided value into the lfsr16 value by counting backwards to get
 188  * the value that needs to be set in the hardware comparator to get the
 189  * same actual count. This makes sense once you read above a couple of
 190  * times and think about it from a hardware perspective.
 191  */
 192 static u16 dlfb_lfsr16(u16 actual_count)
 193 {
 194         u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
 195
 196         while (actual_count--) {
 197                 lv =     ((lv << 1) |
 198                         (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
 199                         & 0xFFFF;
 200         }
 201
 202         return (u16) lv;
 203 }
 204
 205 /*
 206  * This does LFSR conversion on the value that is to be written.
 207  * See LFSR explanation above for more detail.
 208  */
 209 static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
 210 {
 211         return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
 212 }
 213
 214 /*
 215  * This takes a standard fbdev screeninfo struct and all of its monitor mode
 216  * details and converts them into the DisplayLink equivalent register commands.
 217  */
 218 static char *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
 219 {
 220         u16 xds, yds;
 221         u16 xde, yde;
 222         u16 yec;
 223
 224         /* x display start */
 225         xds = var->left_margin + var->hsync_len;
 226         wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
 227         /* x display end */
 228         xde = xds + var->xres;
 229         wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
 230
 231         /* y display start */
 232         yds = var->upper_margin + var->vsync_len;
 233         wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
 234         /* y display end */
 235         yde = yds + var->yres;
 236         wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
 237
 238         /* x end count is active + blanking - 1 */
 239         wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
 240                         xde + var->right_margin - 1);
 241
 242         /* libdlo hardcodes hsync start to 1 */
 243         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
 244
 245         /* hsync end is width of sync pulse + 1 */
 246         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
 247
 248         /* hpixels is active pixels */
 249         wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
 250
 251         /* yendcount is vertical active + vertical blanking */
 252         yec = var->yres + var->upper_margin + var->lower_margin +
 253                         var->vsync_len;
 254         wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
 255
 256         /* libdlo hardcodes vsync start to 0 */
 257         wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
 258
 259         /* vsync end is width of vsync pulse */
 260         wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
 261
 262         /* vpixels is active pixels */
 263         wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
 264
 265         /* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
 266         wrptr = dlfb_set_register_16be(wrptr, 0x1B,
 267                         200*1000*1000/var->pixclock);
 268
 269         return wrptr;
 270 }
 271
 272 /*
 273  * This takes a standard fbdev screeninfo struct that was fetched or prepared
 274  * and then generates the appropriate command sequence that then drives the
 275  * display controller.
 276  */
 277 static int dlfb_set_video_mode(struct dlfb_data *dev,
 278                                 struct fb_var_screeninfo *var)
 279 {
 280         char *buf;
 281         char *wrptr;
 282         int retval = 0;
 283         int writesize;
 284         struct urb *urb;
 285
 286         if (!atomic_read(&dev->usb_active))
 287                 return -EPERM;
 288
 289         urb = dlfb_get_urb(dev);
 290         if (!urb)
 291                 return -ENOMEM;
 292
 293         buf = (char *) urb->transfer_buffer;
 294
 295         /*
 296         * This first section has to do with setting the base address on the
 297         * controller * associated with the display. There are 2 base
 298         * pointers, currently, we only * use the 16 bpp segment.
 299         */
 300         wrptr = dlfb_vidreg_lock(buf);
 301         wrptr = dlfb_set_color_depth(wrptr, 0x00);
 302         /* set base for 16bpp segment to 0 */
 303         wrptr = dlfb_set_base16bpp(wrptr, 0);
 304         /* set base for 8bpp segment to end of fb */
 305         wrptr = dlfb_set_base8bpp(wrptr, dev->info->fix.smem_len);
 306
 307         wrptr = dlfb_set_vid_cmds(wrptr, var);
 308         wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);
 309         wrptr = dlfb_vidreg_unlock(wrptr);
 310
 311         writesize = wrptr - buf;
 312
 313         retval = dlfb_submit_urb(dev, urb, writesize);
 314
 315         dev->blank_mode = FB_BLANK_UNBLANK;
 316
 317         return retval;
 318 }
 319
 320 static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 321 {
 322         unsigned long start = vma->vm_start;
 323         unsigned long size = vma->vm_end - vma->vm_start;
 324         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 325         unsigned long page, pos;
 326
 327         if (offset + size > info->fix.smem_len)
 328                 return -EINVAL;
 329
 330         pos = (unsigned long)info->fix.smem_start + offset;
 331
 332         pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
 333                   pos, size);
 334
 335         while (size > 0) {
 336                 page = vmalloc_to_pfn((void *)pos);
 337                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 338                         return -EAGAIN;
 339
 340                 start += PAGE_SIZE;
 341                 pos += PAGE_SIZE;
 342                 if (size > PAGE_SIZE)
 343                         size -= PAGE_SIZE;
 344                 else
 345                         size = 0;
 346         }
 347
 348         vma->vm_flags |= VM_RESERVED;   /* avoid to swap out this VMA */
 349         return 0;
 350 }
 351
 352 /*
 353  * Trims identical data from front and back of line
 354  * Sets new front buffer address and width
 355  * And returns byte count of identical pixels
 356  * Assumes CPU natural alignment (unsigned long)
 357  * for back and front buffer ptrs and width
 358  */
 359 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 360 {
 361         int j, k;
 362         const unsigned long *back = (const unsigned long *) bback;
 363         const unsigned long *front = (const unsigned long *) *bfront;
 364         const int width = *width_bytes / sizeof(unsigned long);
 365         int identical = width;
 366         int start = width;
 367         int end = width;
 368
 369         prefetch((void *) front);
 370         prefetch((void *) back);
 371
 372         for (j = 0; j < width; j++) {
 373                 if (back[j] != front[j]) {
 374                         start = j;
 375                         break;
 376                 }
 377         }
 378
 379         for (k = width - 1; k > j; k--) {
 380                 if (back[k] != front[k]) {
 381                         end = k+1;
 382                         break;
 383                 }
 384         }
 385
 386         identical = start + (width - end);
 387         *bfront = (u8 *) &front[start];
 388         *width_bytes = (end - start) * sizeof(unsigned long);
 389
 390         return identical * sizeof(unsigned long);
 391 }
 392
 393 /*
 394  * Render a command stream for an encoded horizontal line segment of pixels.
 395  *
 396  * A command buffer holds several commands.
 397  * It always begins with a fresh command header
 398  * (the protocol doesn't require this, but we enforce it to allow
 399  * multiple buffers to be potentially encoded and sent in parallel).
 400  * A single command encodes one contiguous horizontal line of pixels
 401  *
 402  * The function relies on the client to do all allocation, so that
 403  * rendering can be done directly to output buffers (e.g. USB URBs).
 404  * The function fills the supplied command buffer, providing information
 405  * on where it left off, so the client may call in again with additional
 406  * buffers if the line will take several buffers to complete.
 407  *
 408  * A single command can transmit a maximum of 256 pixels,
 409  * regardless of the compression ratio (protocol design limit).
 410  * To the hardware, 0 for a size byte means 256
 411  *
 412  * Rather than 256 pixel commands which are either rl or raw encoded,
 413  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 414  * This has a slightly larger header overhead, but produces more even results.
 415  * It also processes all data (read and write) in a single pass.
 416  * Performance benchmarks of common cases show it having just slightly better
 417  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 418  * But for very rl friendly data, will compress not quite as well.
 419  */
 420 static void dlfb_compress_hline(
 421         const uint16_t **pixel_start_ptr,
 422         const uint16_t *const pixel_end,
 423         uint32_t *device_address_ptr,
 424         uint8_t **command_buffer_ptr,
 425         const uint8_t *const cmd_buffer_end)
 426 {
 427         const uint16_t *pixel = *pixel_start_ptr;
 428         uint32_t dev_addr  = *device_address_ptr;
 429         uint8_t *cmd = *command_buffer_ptr;
 430         const int bpp = 2;
 431
 432         while ((pixel_end > pixel) &&
 433                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 434                 uint8_t *raw_pixels_count_byte = 0;
 435                 uint8_t *cmd_pixels_count_byte = 0;
 436                 const uint16_t *raw_pixel_start = 0;
 437                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = 0;
 438
 439                 prefetchw((void *) cmd); /* pull in one cache line at least */
 440
 441                 *cmd++ = 0xAF;
 442                 *cmd++ = 0x6B;
 443                 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
 444                 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
 445                 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
 446
 447                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 448                 cmd_pixel_start = pixel;
 449
 450                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 451                 raw_pixel_start = pixel;
 452
 453                 cmd_pixel_end = pixel + min(MAX_CMD_PIXELS + 1,
 454                         min((int)(pixel_end - pixel),
 455                             (int)(cmd_buffer_end - cmd) / bpp));
 456
 457                 prefetch_range((void *) pixel, (cmd_pixel_end - pixel) * bpp);
 458
 459                 while (pixel < cmd_pixel_end) {
 460                         const uint16_t * const repeating_pixel = pixel;
 461
 462                         *(uint16_t *)cmd = cpu_to_be16p(pixel);
 463                         cmd += 2;
 464                         pixel++;
 465
 466                         if (unlikely((pixel < cmd_pixel_end) &&
 467                                      (*pixel == *repeating_pixel))) {
 468                                 /* go back and fill in raw pixel count */
 469                                 *raw_pixels_count_byte = ((repeating_pixel -
 470                                                 raw_pixel_start) + 1) & 0xFF;
 471
 472                                 while ((pixel < cmd_pixel_end)
 473                                        && (*pixel == *repeating_pixel)) {
 474                                         pixel++;
 475                                 }
 476
 477                                 /* immediately after raw data is repeat byte */
 478                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 479
 480                                 /* Then start another raw pixel span */
 481                                 raw_pixel_start = pixel;
 482                                 raw_pixels_count_byte = cmd++;
 483                         }
 484                 }
 485
 486                 if (pixel > raw_pixel_start) {
 487                         /* finalize last RAW span */
 488                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 489                 }
 490
 491                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 492                 dev_addr += (pixel - cmd_pixel_start) * bpp;
 493         }
 494
 495         if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
 496                 /* Fill leftover bytes with no-ops */
 497                 if (cmd_buffer_end > cmd)
 498                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 499                 cmd = (uint8_t *) cmd_buffer_end;
 500         }
 501
 502         *command_buffer_ptr = cmd;
 503         *pixel_start_ptr = pixel;
 504         *device_address_ptr = dev_addr;
 505
 506         return;
 507 }
 508
 509 /*
 510  * There are 3 copies of every pixel: The front buffer that the fbdev
 511  * client renders to, the actual framebuffer across the USB bus in hardware
 512  * (that we can only write to, slowly, and can never read), and (optionally)
 513  * our shadow copy that tracks what's been sent to that hardware buffer.
 514  */
 515 static int dlfb_render_hline(struct dlfb_data *dev, struct urb **urb_ptr,
 516                               const char *front, char **urb_buf_ptr,
 517                               u32 byte_offset, u32 byte_width,
 518                               int *ident_ptr, int *sent_ptr)
 519 {
 520         const u8 *line_start, *line_end, *next_pixel;
 521         u32 dev_addr = dev->base16 + byte_offset;
 522         struct urb *urb = *urb_ptr;
 523         u8 *cmd = *urb_buf_ptr;
 524         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 525
 526         line_start = (u8 *) (front + byte_offset);
 527         next_pixel = line_start;
 528         line_end = next_pixel + byte_width;
 529
 530         if (dev->backing_buffer) {
 531                 int offset;
 532                 const u8 *back_start = (u8 *) (dev->backing_buffer
 533                                                 + byte_offset);
 534
 535                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 536                         &byte_width);
 537
 538                 offset = next_pixel - line_start;
 539                 line_end = next_pixel + byte_width;
 540                 dev_addr += offset;
 541                 back_start += offset;
 542                 line_start += offset;
 543
 544                 memcpy((char *)back_start, (char *) line_start,
 545                        byte_width);
 546         }
 547
 548         while (next_pixel < line_end) {
 549
 550                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 551                              (const uint16_t *) line_end, &dev_addr,
 552                         (u8 **) &cmd, (u8 *) cmd_end);
 553
 554                 if (cmd >= cmd_end) {
 555                         int len = cmd - (u8 *) urb->transfer_buffer;
 556                         if (dlfb_submit_urb(dev, urb, len))
 557                                 return 1; /* lost pixels is set */
 558                         *sent_ptr += len;
 559                         urb = dlfb_get_urb(dev);
 560                         if (!urb)
 561                                 return 1; /* lost_pixels is set */
 562                         *urb_ptr = urb;
 563                         cmd = urb->transfer_buffer;
 564                         cmd_end = &cmd[urb->transfer_buffer_length];
 565                 }
 566         }
 567
 568         *urb_buf_ptr = cmd;
 569
 570         return 0;
 571 }
 572
 573 int dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
 574                int width, int height, char *data)
 575 {
 576         int i, ret;
 577         char *cmd;
 578         cycles_t start_cycles, end_cycles;
 579         int bytes_sent = 0;
 580         int bytes_identical = 0;
 581         struct urb *urb;
 582         int aligned_x;
 583
 584         start_cycles = get_cycles();
 585
 586         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 587         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 588         x = aligned_x;
 589
 590         if ((width <= 0) ||
 591             (x + width > dev->info->var.xres) ||
 592             (y + height > dev->info->var.yres))
 593                 return -EINVAL;
 594
 595         if (!atomic_read(&dev->usb_active))
 596                 return 0;
 597
 598         urb = dlfb_get_urb(dev);
 599         if (!urb)
 600                 return 0;
 601         cmd = urb->transfer_buffer;
 602
 603         for (i = y; i < y + height ; i++) {
 604                 const int line_offset = dev->info->fix.line_length * i;
 605                 const int byte_offset = line_offset + (x * BPP);
 606
 607                 if (dlfb_render_hline(dev, &urb,
 608                                       (char *) dev->info->fix.smem_start,
 609                                       &cmd, byte_offset, width * BPP,
 610                                       &bytes_identical, &bytes_sent))
 611                         goto error;
 612         }
 613
 614         if (cmd > (char *) urb->transfer_buffer) {
 615                 /* Send partial buffer remaining before exiting */
 616                 int len = cmd - (char *) urb->transfer_buffer;
 617                 ret = dlfb_submit_urb(dev, urb, len);
 618                 bytes_sent += len;
 619         } else
 620                 dlfb_urb_completion(urb);
 621
 622 error:
 623         atomic_add(bytes_sent, &dev->bytes_sent);
 624         atomic_add(bytes_identical, &dev->bytes_identical);
 625         atomic_add(width*height*2, &dev->bytes_rendered);
 626         end_cycles = get_cycles();
 627         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 628                     >> 10)), /* Kcycles */
 629                    &dev->cpu_kcycles_used);
 630
 631         return 0;
 632 }
 633
 634 /*
 635  * Path triggered by usermode clients who write to filesystem
 636  * e.g. cat filename > /dev/fb1
 637  * Not used by X Windows or text-mode console. But useful for testing.
 638  * Slow because of extra copy and we must assume all pixels dirty.
 639  */
 640 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
 641                           size_t count, loff_t *ppos)
 642 {
 643         ssize_t result;
 644         struct dlfb_data *dev = info->par;
 645         u32 offset = (u32) *ppos;
 646
 647         result = fb_sys_write(info, buf, count, ppos);
 648
 649         if (result > 0) {
 650                 int start = max((int)(offset / info->fix.line_length) - 1, 0);
 651                 int lines = min((u32)((result / info->fix.line_length) + 1),
 652                                 (u32)info->var.yres);
 653
 654                 dlfb_handle_damage(dev, 0, start, info->var.xres,
 655                         lines, info->screen_base);
 656         }
 657
 658         return result;
 659 }
 660
 661 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 662 static void dlfb_ops_copyarea(struct fb_info *info,
 663                                 const struct fb_copyarea *area)
 664 {
 665
 666         struct dlfb_data *dev = info->par;
 667
 668         sys_copyarea(info, area);
 669
 670         dlfb_handle_damage(dev, area->dx, area->dy,
 671                         area->width, area->height, info->screen_base);
 672 }
 673
 674 static void dlfb_ops_imageblit(struct fb_info *info,
 675                                 const struct fb_image *image)
 676 {
 677         struct dlfb_data *dev = info->par;
 678
 679         sys_imageblit(info, image);
 680
 681         dlfb_handle_damage(dev, image->dx, image->dy,
 682                         image->width, image->height, info->screen_base);
 683 }
 684
 685 static void dlfb_ops_fillrect(struct fb_info *info,
 686                           const struct fb_fillrect *rect)
 687 {
 688         struct dlfb_data *dev = info->par;
 689
 690         sys_fillrect(info, rect);
 691
 692         dlfb_handle_damage(dev, rect->dx, rect->dy, rect->width,
 693                               rect->height, info->screen_base);
 694 }
 695
 696 /*
 697  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 698  *   Touching ANY framebuffer memory that triggers a page fault
 699  *   in fb_defio will cause a deadlock, when it also tries to
 700  *   grab the same mutex.
 701  */
 702 static void dlfb_dpy_deferred_io(struct fb_info *info,
 703                                 struct list_head *pagelist)
 704 {
 705         struct page *cur;
 706         struct fb_deferred_io *fbdefio = info->fbdefio;
 707         struct dlfb_data *dev = info->par;
 708         struct urb *urb;
 709         char *cmd;
 710         cycles_t start_cycles, end_cycles;
 711         int bytes_sent = 0;
 712         int bytes_identical = 0;
 713         int bytes_rendered = 0;
 714
 715         if (!fb_defio)
 716                 return;
 717
 718         if (!atomic_read(&dev->usb_active))
 719                 return;
 720
 721         start_cycles = get_cycles();
 722
 723         urb = dlfb_get_urb(dev);
 724         if (!urb)
 725                 return;
 726
 727         cmd = urb->transfer_buffer;
 728
 729         /* walk the written page list and render each to device */
 730         list_for_each_entry(cur, &fbdefio->pagelist, lru) {
 731
 732                 if (dlfb_render_hline(dev, &urb, (char *) info->fix.smem_start,
 733                                   &cmd, cur->index << PAGE_SHIFT,
 734                                   PAGE_SIZE, &bytes_identical, &bytes_sent))
 735                         goto error;
 736                 bytes_rendered += PAGE_SIZE;
 737         }
 738
 739         if (cmd > (char *) urb->transfer_buffer) {
 740                 /* Send partial buffer remaining before exiting */
 741                 int len = cmd - (char *) urb->transfer_buffer;
 742                 dlfb_submit_urb(dev, urb, len);
 743                 bytes_sent += len;
 744         } else
 745                 dlfb_urb_completion(urb);
 746
 747 error:
 748         atomic_add(bytes_sent, &dev->bytes_sent);
 749         atomic_add(bytes_identical, &dev->bytes_identical);
 750         atomic_add(bytes_rendered, &dev->bytes_rendered);
 751         end_cycles = get_cycles();
 752         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 753                     >> 10)), /* Kcycles */
 754                    &dev->cpu_kcycles_used);
 755 }
 756
 757 static int dlfb_get_edid(struct dlfb_data *dev, char *edid, int len)
 758 {
 759         int i;
 760         int ret;
 761         char *rbuf;
 762
 763         rbuf = kmalloc(2, GFP_KERNEL);
 764         if (!rbuf)
 765                 return 0;
 766
 767         for (i = 0; i < len; i++) {
 768                 ret = usb_control_msg(dev->udev,
 769                                     usb_rcvctrlpipe(dev->udev, 0), (0x02),
 770                                     (0x80 | (0x02 << 5)), i << 8, 0xA1, rbuf, 2,
 771                                     HZ);
 772                 if (ret < 1) {
 773                         pr_err("Read EDID byte %d failed err %x\n", i, ret);
 774                         i--;
 775                         break;
 776                 }
 777                 edid[i] = rbuf[1];
 778         }
 779
 780         kfree(rbuf);
 781
 782         return i;
 783 }
 784
 785 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
 786                                 unsigned long arg)
 787 {
 788
 789         struct dlfb_data *dev = info->par;
 790
 791         if (!atomic_read(&dev->usb_active))
 792                 return 0;
 793
 794         /* TODO: Update X server to get this from sysfs instead */
 795         if (cmd == DLFB_IOCTL_RETURN_EDID) {
 796                 void __user *edid = (void __user *)arg;
 797                 if (copy_to_user(edid, dev->edid, dev->edid_size))
 798                         return -EFAULT;
 799                 return 0;
 800         }
 801
 802         /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
 803         if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
 804                 struct dloarea area;
 805
 806                 if (copy_from_user(&area, (void __user *)arg,
 807                                   sizeof(struct dloarea)))
 808                         return -EFAULT;
 809
 810                 /*
 811                  * If we have a damage-aware client, turn fb_defio "off"
 812                  * To avoid perf imact of unnecessary page fault handling.
 813                  * Done by resetting the delay for this fb_info to a very
 814                  * long period. Pages will become writable and stay that way.
 815                  * Reset to normal value when all clients have closed this fb.
 816                  */
 817                 if (info->fbdefio)
 818                         info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 819
 820                 if (area.x < 0)
 821                         area.x = 0;
 822
 823                 if (area.x > info->var.xres)
 824                         area.x = info->var.xres;
 825
 826                 if (area.y < 0)
 827                         area.y = 0;
 828
 829                 if (area.y > info->var.yres)
 830                         area.y = info->var.yres;
 831
 832                 dlfb_handle_damage(dev, area.x, area.y, area.w, area.h,
 833                            info->screen_base);
 834         }
 835
 836         return 0;
 837 }
 838
 839 /* taken from vesafb */
 840 static int
 841 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
 842                unsigned blue, unsigned transp, struct fb_info *info)
 843 {
 844         int err = 0;
 845
 846         if (regno >= info->cmap.len)
 847                 return 1;
 848
 849         if (regno < 16) {
 850                 if (info->var.red.offset == 10) {
 851                         /* 1:5:5:5 */
 852                         ((u32 *) (info->pseudo_palette))[regno] =
 853                             ((red & 0xf800) >> 1) |
 854                             ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
 855                 } else {
 856                         /* 0:5:6:5 */
 857                         ((u32 *) (info->pseudo_palette))[regno] =
 858                             ((red & 0xf800)) |
 859                             ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
 860                 }
 861         }
 862
 863         return err;
 864 }
 865
 866 /*
 867  * It's common for several clients to have framebuffer open simultaneously.
 868  * e.g. both fbcon and X. Makes things interesting.
 869  * Assumes caller is holding info->lock (for open and release at least)
 870  */
 871 static int dlfb_ops_open(struct fb_info *info, int user)
 872 {
 873         struct dlfb_data *dev = info->par;
 874
 875         /*
 876          * fbcon aggressively connects to first framebuffer it finds,
 877          * preventing other clients (X) from working properly. Usually
 878          * not what the user wants. Fail by default with option to enable.
 879          */
 880         if ((user == 0) && (!console))
 881                 return -EBUSY;
 882
 883         /* If the USB device is gone, we don't accept new opens */
 884         if (dev->virtualized)
 885                 return -ENODEV;
 886
 887         dev->fb_count++;
 888
 889         kref_get(&dev->kref);
 890
 891         if (fb_defio && (info->fbdefio == NULL)) {
 892                 /* enable defio at last moment if not disabled by client */
 893
 894                 struct fb_deferred_io *fbdefio;
 895
 896                 fbdefio = kmalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 897
 898                 if (fbdefio) {
 899                         fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 900                         fbdefio->deferred_io = dlfb_dpy_deferred_io;
 901                 }
 902
 903                 info->fbdefio = fbdefio;
 904                 fb_deferred_io_init(info);
 905         }
 906
 907         pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
 908             info->node, user, info, dev->fb_count);
 909
 910         return 0;
 911 }
 912
 913 /*
 914  * Called when all client interfaces to start transactions have been disabled,
 915  * and all references to our device instance (dlfb_data) are released.
 916  * Every transaction must have a reference, so we know are fully spun down
 917  */
 918 static void dlfb_free(struct kref *kref)
 919 {
 920         struct dlfb_data *dev = container_of(kref, struct dlfb_data, kref);
 921
 922         if (dev->backing_buffer)
 923                 vfree(dev->backing_buffer);
 924
 925         kfree(dev->edid);
 926
 927         pr_warn("freeing dlfb_data %p\n", dev);
 928
 929         kfree(dev);
 930 }
 931
 932 static void dlfb_release_urb_work(struct work_struct *work)
 933 {
 934         struct urb_node *unode = container_of(work, struct urb_node,
 935                                               release_urb_work.work);
 936
 937         up(&unode->dev->urbs.limit_sem);
 938 }
 939
 940 static void dlfb_free_framebuffer(struct dlfb_data *dev)
 941 {
 942         struct fb_info *info = dev->info;
 943
 944         if (info) {
 945                 int node = info->node;
 946
 947                 unregister_framebuffer(info);
 948
 949                 if (info->cmap.len != 0)
 950                         fb_dealloc_cmap(&info->cmap);
 951                 if (info->monspecs.modedb)
 952                         fb_destroy_modedb(info->monspecs.modedb);
 953                 if (info->screen_base)
 954                         vfree(info->screen_base);
 955
 956                 fb_destroy_modelist(&info->modelist);
 957
 958                 dev->info = NULL;
 959
 960                 /* Assume info structure is freed after this point */
 961                 framebuffer_release(info);
 962
 963                 pr_warn("fb_info for /dev/fb%d has been freed\n", node);
 964         }
 965
 966         /* ref taken in probe() as part of registering framebfufer */
 967         kref_put(&dev->kref, dlfb_free);
 968 }
 969
 970 static void dlfb_free_framebuffer_work(struct work_struct *work)
 971 {
 972         struct dlfb_data *dev = container_of(work, struct dlfb_data,
 973                                              free_framebuffer_work.work);
 974         dlfb_free_framebuffer(dev);
 975 }
 976 /*
 977  * Assumes caller is holding info->lock mutex (for open and release at least)
 978  */
 979 static int dlfb_ops_release(struct fb_info *info, int user)
 980 {
 981         struct dlfb_data *dev = info->par;
 982
 983         dev->fb_count--;
 984
 985         /* We can't free fb_info here - fbmem will touch it when we return */
 986         if (dev->virtualized && (dev->fb_count == 0))
 987                 schedule_delayed_work(&dev->free_framebuffer_work, HZ);
 988
 989         if ((dev->fb_count == 0) && (info->fbdefio)) {
 990                 fb_deferred_io_cleanup(info);
 991                 kfree(info->fbdefio);
 992                 info->fbdefio = NULL;
 993                 info->fbops->fb_mmap = dlfb_ops_mmap;
 994         }
 995
 996         pr_warn("released /dev/fb%d user=%d count=%d\n",
 997                   info->node, user, dev->fb_count);
 998
 999         kref_put(&dev->kref, dlfb_free);
1000
1001         return 0;
1002 }
1003
1004 /*
1005  * Check whether a video mode is supported by the DisplayLink chip
1006  * We start from monitor's modes, so don't need to filter that here
1007  */
1008 static int dlfb_is_valid_mode(struct fb_videomode *mode,
1009                 struct fb_info *info)
1010 {
1011         struct dlfb_data *dev = info->par;
1012
1013         if (mode->xres * mode->yres > dev->sku_pixel_limit) {
1014                 pr_warn("%dx%d beyond chip capabilities\n",
1015                        mode->xres, mode->yres);
1016                 return 0;
1017         }
1018
1019         pr_info("%dx%d @ %d Hz valid mode\n", mode->xres, mode->yres,
1020                 mode->refresh);
1021
1022         return 1;
1023 }
1024
1025 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1026 {
1027         const struct fb_bitfield red = { 11, 5, 0 };
1028         const struct fb_bitfield green = { 5, 6, 0 };
1029         const struct fb_bitfield blue = { 0, 5, 0 };
1030
1031         var->bits_per_pixel = 16;
1032         var->red = red;
1033         var->green = green;
1034         var->blue = blue;
1035 }
1036
1037 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1038                                 struct fb_info *info)
1039 {
1040         struct fb_videomode mode;
1041
1042         /* TODO: support dynamically changing framebuffer size */
1043         if ((var->xres * var->yres * 2) > info->fix.smem_len)
1044                 return -EINVAL;
1045
1046         /* set device-specific elements of var unrelated to mode */
1047         dlfb_var_color_format(var);
1048
1049         fb_var_to_videomode(&mode, var);
1050
1051         if (!dlfb_is_valid_mode(&mode, info))
1052                 return -EINVAL;
1053
1054         return 0;
1055 }
1056
1057 static int dlfb_ops_set_par(struct fb_info *info)
1058 {
1059         struct dlfb_data *dev = info->par;
1060         int result;
1061         u16 *pix_framebuffer;
1062         int i;
1063
1064         pr_notice("set_par mode %dx%d\n", info->var.xres, info->var.yres);
1065
1066         result = dlfb_set_video_mode(dev, &info->var);
1067
1068         if ((result == 0) && (dev->fb_count == 0)) {
1069
1070                 /* paint greenscreen */
1071
1072                 pix_framebuffer = (u16 *) info->screen_base;
1073                 for (i = 0; i < info->fix.smem_len / 2; i++)
1074                         pix_framebuffer[i] = 0x37e6;
1075
1076                 dlfb_handle_damage(dev, 0, 0, info->var.xres, info->var.yres,
1077                                    info->screen_base);
1078         }
1079
1080         return result;
1081 }
1082
1083 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1084 static char *dlfb_dummy_render(char *buf)
1085 {
1086         *buf++ = 0xAF;
1087         *buf++ = 0x6A; /* copy */
1088         *buf++ = 0x00; /* from address*/
1089         *buf++ = 0x00;
1090         *buf++ = 0x00;
1091         *buf++ = 0x01; /* one pixel */
1092         *buf++ = 0x00; /* to address */
1093         *buf++ = 0x00;
1094         *buf++ = 0x00;
1095         return buf;
1096 }
1097
1098 /*
1099  * In order to come back from full DPMS off, we need to set the mode again
1100  */
1101 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1102 {
1103         struct dlfb_data *dev = info->par;
1104         char *bufptr;
1105         struct urb *urb;
1106
1107         pr_info("/dev/fb%d FB_BLANK mode %d --> %d\n",
1108                 info->node, dev->blank_mode, blank_mode);
1109
1110         if ((dev->blank_mode == FB_BLANK_POWERDOWN) &&
1111             (blank_mode != FB_BLANK_POWERDOWN)) {
1112
1113                 /* returning from powerdown requires a fresh modeset */
1114                 dlfb_set_video_mode(dev, &info->var);
1115         }
1116
1117         urb = dlfb_get_urb(dev);
1118         if (!urb)
1119                 return 0;
1120
1121         bufptr = (char *) urb->transfer_buffer;
1122         bufptr = dlfb_vidreg_lock(bufptr);
1123         bufptr = dlfb_blanking(bufptr, blank_mode);
1124         bufptr = dlfb_vidreg_unlock(bufptr);
1125
1126         /* seems like a render op is needed to have blank change take effect */
1127         bufptr = dlfb_dummy_render(bufptr);
1128
1129         dlfb_submit_urb(dev, urb, bufptr -
1130                         (char *) urb->transfer_buffer);
1131
1132         dev->blank_mode = blank_mode;
1133
1134         return 0;
1135 }
1136
1137 static struct fb_ops dlfb_ops = {
1138         .owner = THIS_MODULE,
1139         .fb_read = fb_sys_read,
1140         .fb_write = dlfb_ops_write,
1141         .fb_setcolreg = dlfb_ops_setcolreg,
1142         .fb_fillrect = dlfb_ops_fillrect,
1143         .fb_copyarea = dlfb_ops_copyarea,
1144         .fb_imageblit = dlfb_ops_imageblit,
1145         .fb_mmap = dlfb_ops_mmap,
1146         .fb_ioctl = dlfb_ops_ioctl,
1147         .fb_open = dlfb_ops_open,
1148         .fb_release = dlfb_ops_release,
1149         .fb_blank = dlfb_ops_blank,
1150         .fb_check_var = dlfb_ops_check_var,
1151         .fb_set_par = dlfb_ops_set_par,
1152 };
1153
1154
1155 /*
1156  * Assumes &info->lock held by caller
1157  * Assumes no active clients have framebuffer open
1158  */
1159 static int dlfb_realloc_framebuffer(struct dlfb_data *dev, struct fb_info *info)
1160 {
1161         int retval = -ENOMEM;
1162         int old_len = info->fix.smem_len;
1163         int new_len;
1164         unsigned char *old_fb = info->screen_base;
1165         unsigned char *new_fb;
1166         unsigned char *new_back = 0;
1167
1168         pr_warn("Reallocating framebuffer. Addresses will change!\n");
1169
1170         new_len = info->fix.line_length * info->var.yres;
1171
1172         if (PAGE_ALIGN(new_len) > old_len) {
1173                 /*
1174                  * Alloc system memory for virtual framebuffer
1175                  */
1176                 new_fb = vmalloc(new_len);
1177                 if (!new_fb) {
1178                         pr_err("Virtual framebuffer alloc failed\n");
1179                         goto error;
1180                 }
1181
1182                 if (info->screen_base) {
1183                         memcpy(new_fb, old_fb, old_len);
1184                         vfree(info->screen_base);
1185                 }
1186
1187                 info->screen_base = new_fb;
1188                 info->fix.smem_len = PAGE_ALIGN(new_len);
1189                 info->fix.smem_start = (unsigned long) new_fb;
1190                 info->flags = udlfb_info_flags;
1191
1192                 /*
1193                  * Second framebuffer copy to mirror the framebuffer state
1194                  * on the physical USB device. We can function without this.
1195                  * But with imperfect damage info we may send pixels over USB
1196                  * that were, in fact, unchanged - wasting limited USB bandwidth
1197                  */
1198                 if (shadow)
1199                         new_back = vzalloc(new_len);
1200                 if (!new_back)
1201                         pr_info("No shadow/backing buffer allocated\n");
1202                 else {
1203                         if (dev->backing_buffer)
1204                                 vfree(dev->backing_buffer);
1205                         dev->backing_buffer = new_back;
1206                 }
1207         }
1208
1209         retval = 0;
1210
1211 error:
1212         return retval;
1213 }
1214
1215 /*
1216  * 1) Get EDID from hw, or use sw default
1217  * 2) Parse into various fb_info structs
1218  * 3) Allocate virtual framebuffer memory to back highest res mode
1219  *
1220  * Parses EDID into three places used by various parts of fbdev:
1221  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1222  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1223  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1224  *
1225  * If EDID is not readable/valid, then modelist is all VESA modes,
1226  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1227  * Returns 0 if successful
1228  */
1229 static int dlfb_setup_modes(struct dlfb_data *dev,
1230                            struct fb_info *info,
1231                            char *default_edid, size_t default_edid_size)
1232 {
1233         int i;
1234         const struct fb_videomode *default_vmode = NULL;
1235         int result = 0;
1236         char *edid;
1237         int tries = 3;
1238
1239         if (info->dev) /* only use mutex if info has been registered */
1240                 mutex_lock(&info->lock);
1241
1242         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1243         if (!edid) {
1244                 result = -ENOMEM;
1245                 goto error;
1246         }
1247
1248         fb_destroy_modelist(&info->modelist);
1249         memset(&info->monspecs, 0, sizeof(info->monspecs));
1250
1251         /*
1252          * Try to (re)read EDID from hardware first
1253          * EDID data may return, but not parse as valid
1254          * Try again a few times, in case of e.g. analog cable noise
1255          */
1256         while (tries--) {
1257
1258                 i = dlfb_get_edid(dev, edid, EDID_LENGTH);
1259
1260                 if (i >= EDID_LENGTH)
1261                         fb_edid_to_monspecs(edid, &info->monspecs);
1262
1263                 if (info->monspecs.modedb_len > 0) {
1264                         dev->edid = edid;
1265                         dev->edid_size = i;
1266                         break;
1267                 }
1268         }
1269
1270         /* If that fails, use a previously returned EDID if available */
1271         if (info->monspecs.modedb_len == 0) {
1272
1273                 pr_err("Unable to get valid EDID from device/display\n");
1274
1275                 if (dev->edid) {
1276                         fb_edid_to_monspecs(dev->edid, &info->monspecs);
1277                         if (info->monspecs.modedb_len > 0)
1278                                 pr_err("Using previously queried EDID\n");
1279                 }
1280         }
1281
1282         /* If that fails, use the default EDID we were handed */
1283         if (info->monspecs.modedb_len == 0) {
1284                 if (default_edid_size >= EDID_LENGTH) {
1285                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1286                         if (info->monspecs.modedb_len > 0) {
1287                                 memcpy(edid, default_edid, default_edid_size);
1288                                 dev->edid = edid;
1289                                 dev->edid_size = default_edid_size;
1290                                 pr_err("Using default/backup EDID\n");
1291                         }
1292                 }
1293         }
1294
1295         /* If we've got modes, let's pick a best default mode */
1296         if (info->monspecs.modedb_len > 0) {
1297
1298                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1299                         if (dlfb_is_valid_mode(&info->monspecs.modedb[i], info))
1300                                 fb_add_videomode(&info->monspecs.modedb[i],
1301                                         &info->modelist);
1302                         else {
1303                                 if (i == 0)
1304                                         /* if we've removed top/best mode */
1305                                         info->monspecs.misc
1306                                                 &= ~FB_MISC_1ST_DETAIL;
1307                         }
1308                 }
1309
1310                 default_vmode = fb_find_best_display(&info->monspecs,
1311                                                      &info->modelist);
1312         }
1313
1314         /* If everything else has failed, fall back to safe default mode */
1315         if (default_vmode == NULL) {
1316
1317                 struct fb_videomode fb_vmode = {0};
1318
1319                 /*
1320                  * Add the standard VESA modes to our modelist
1321                  * Since we don't have EDID, there may be modes that
1322                  * overspec monitor and/or are incorrect aspect ratio, etc.
1323                  * But at least the user has a chance to choose
1324                  */
1325                 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
1326                         if (dlfb_is_valid_mode((struct fb_videomode *)
1327                                                 &vesa_modes[i], info))
1328                                 fb_add_videomode(&vesa_modes[i],
1329                                                  &info->modelist);
1330                 }
1331
1332                 /*
1333                  * default to resolution safe for projectors
1334                  * (since they are most common case without EDID)
1335                  */
1336                 fb_vmode.xres = 800;
1337                 fb_vmode.yres = 600;
1338                 fb_vmode.refresh = 60;
1339                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1340                                                      &info->modelist);
1341         }
1342
1343         /* If we have good mode and no active clients*/
1344         if ((default_vmode != NULL) && (dev->fb_count == 0)) {
1345
1346                 fb_videomode_to_var(&info->var, default_vmode);
1347                 dlfb_var_color_format(&info->var);
1348
1349                 /*
1350                  * with mode size info, we can now alloc our framebuffer.
1351                  */
1352                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1353                 info->fix.line_length = info->var.xres *
1354                         (info->var.bits_per_pixel / 8);
1355
1356                 result = dlfb_realloc_framebuffer(dev, info);
1357
1358         } else
1359                 result = -EINVAL;
1360
1361 error:
1362         if (edid && (dev->edid != edid))
1363                 kfree(edid);
1364
1365         if (info->dev)
1366                 mutex_unlock(&info->lock);
1367
1368         return result;
1369 }
1370
1371 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1372                                    struct device_attribute *a, char *buf) {
1373         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1374         struct dlfb_data *dev = fb_info->par;
1375         return snprintf(buf, PAGE_SIZE, "%u\n",
1376                         atomic_read(&dev->bytes_rendered));
1377 }
1378
1379 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1380                                    struct device_attribute *a, char *buf) {
1381         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1382         struct dlfb_data *dev = fb_info->par;
1383         return snprintf(buf, PAGE_SIZE, "%u\n",
1384                         atomic_read(&dev->bytes_identical));
1385 }
1386
1387 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1388                                    struct device_attribute *a, char *buf) {
1389         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1390         struct dlfb_data *dev = fb_info->par;
1391         return snprintf(buf, PAGE_SIZE, "%u\n",
1392                         atomic_read(&dev->bytes_sent));
1393 }
1394
1395 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1396                                    struct device_attribute *a, char *buf) {
1397         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1398         struct dlfb_data *dev = fb_info->par;
1399         return snprintf(buf, PAGE_SIZE, "%u\n",
1400                         atomic_read(&dev->cpu_kcycles_used));
1401 }
1402
1403 static ssize_t edid_show(
1404                         struct file *filp,
1405                         struct kobject *kobj, struct bin_attribute *a,
1406                          char *buf, loff_t off, size_t count) {
1407         struct device *fbdev = container_of(kobj, struct device, kobj);
1408         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1409         struct dlfb_data *dev = fb_info->par;
1410
1411         if (dev->edid == NULL)
1412                 return 0;
1413
1414         if ((off >= dev->edid_size) || (count > dev->edid_size))
1415                 return 0;
1416
1417         if (off + count > dev->edid_size)
1418                 count = dev->edid_size - off;
1419
1420         pr_info("sysfs edid copy %p to %p, %d bytes\n",
1421                 dev->edid, buf, (int) count);
1422
1423         memcpy(buf, dev->edid, count);
1424
1425         return count;
1426 }
1427
1428 static ssize_t edid_store(
1429                         struct file *filp,
1430                         struct kobject *kobj, struct bin_attribute *a,
1431                         char *src, loff_t src_off, size_t src_size) {
1432         struct device *fbdev = container_of(kobj, struct device, kobj);
1433         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1434         struct dlfb_data *dev = fb_info->par;
1435         int ret;
1436
1437         /* We only support write of entire EDID at once, no offset*/
1438         if ((src_size != EDID_LENGTH) || (src_off != 0))
1439                 return -EINVAL;
1440
1441         ret = dlfb_setup_modes(dev, fb_info, src, src_size);
1442         if (ret)
1443                 return ret;
1444
1445         if (!dev->edid || memcmp(src, dev->edid, src_size))
1446                 return -EINVAL;
1447
1448         pr_info("sysfs written EDID is new default\n");
1449         dlfb_ops_set_par(fb_info);
1450         return src_size;
1451 }
1452
1453 static ssize_t metrics_reset_store(struct device *fbdev,
1454                            struct device_attribute *attr,
1455                            const char *buf, size_t count)
1456 {
1457         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1458         struct dlfb_data *dev = fb_info->par;
1459
1460         atomic_set(&dev->bytes_rendered, 0);
1461         atomic_set(&dev->bytes_identical, 0);
1462         atomic_set(&dev->bytes_sent, 0);
1463         atomic_set(&dev->cpu_kcycles_used, 0);
1464
1465         return count;
1466 }
1467
1468 static struct bin_attribute edid_attr = {
1469         .attr.name = "edid",
1470         .attr.mode = 0666,
1471         .size = EDID_LENGTH,
1472         .read = edid_show,
1473         .write = edid_store
1474 };
1475
1476 static struct device_attribute fb_device_attrs[] = {
1477         __ATTR_RO(metrics_bytes_rendered),
1478         __ATTR_RO(metrics_bytes_identical),
1479         __ATTR_RO(metrics_bytes_sent),
1480         __ATTR_RO(metrics_cpu_kcycles_used),
1481         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1482 };
1483
1484 /*
1485  * This is necessary before we can communicate with the display controller.
1486  */
1487 static int dlfb_select_std_channel(struct dlfb_data *dev)
1488 {
1489         int ret;
1490         u8 set_def_chn[] = {       0x57, 0xCD, 0xDC, 0xA7,
1491                                 0x1C, 0x88, 0x5E, 0x15,
1492                                 0x60, 0xFE, 0xC6, 0x97,
1493                                 0x16, 0x3D, 0x47, 0xF2  };
1494
1495         ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1496                         NR_USB_REQUEST_CHANNEL,
1497                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1498                         set_def_chn, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
1499         return ret;
1500 }
1501
1502 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dev,
1503                                         struct usb_interface *interface)
1504 {
1505         char *desc;
1506         char *buf;
1507         char *desc_end;
1508
1509         int total_len = 0;
1510
1511         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1512         if (!buf)
1513                 return false;
1514         desc = buf;
1515
1516         total_len = usb_get_descriptor(interface_to_usbdev(interface),
1517                                         0x5f, /* vendor specific */
1518                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1519
1520         /* if not found, look in configuration descriptor */
1521         if (total_len < 0) {
1522                 if (0 == usb_get_extra_descriptor(interface->cur_altsetting,
1523                         0x5f, &desc))
1524                         total_len = (int) desc[0];
1525         }
1526
1527         if (total_len > 5) {
1528                 pr_info("vendor descriptor length:%x data:%02x %02x %02x %02x" \
1529                         "%02x %02x %02x %02x %02x %02x %02x\n",
1530                         total_len, desc[0],
1531                         desc[1], desc[2], desc[3], desc[4], desc[5], desc[6],
1532                         desc[7], desc[8], desc[9], desc[10]);
1533
1534                 if ((desc[0] != total_len) || /* descriptor length */
1535                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1536                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1537                     (desc[3] != 0x00) ||
1538                     (desc[4] != total_len - 2)) /* length after type */
1539                         goto unrecognized;
1540
1541                 desc_end = desc + total_len;
1542                 desc += 5; /* the fixed header we've already parsed */
1543
1544                 while (desc < desc_end) {
1545                         u8 length;
1546                         u16 key;
1547
1548                         key = le16_to_cpu(*((u16 *) desc));
1549                         desc += sizeof(u16);
1550                         length = *desc;
1551                         desc++;
1552
1553                         switch (key) {
1554                         case 0x0200: { /* max_area */
1555                                 u32 max_area;
1556                                 max_area = le32_to_cpu(*((u32 *)desc));
1557                                 pr_warn("DL chip limited to %d pixel modes\n",
1558                                         max_area);
1559                                 dev->sku_pixel_limit = max_area;
1560                                 break;
1561                         }
1562                         default:
1563                                 break;
1564                         }
1565                         desc += length;
1566                 }
1567         } else {
1568                 pr_info("vendor descriptor not available (%d)\n", total_len);
1569         }
1570
1571         goto success;
1572
1573 unrecognized:
1574         /* allow udlfb to load for now even if firmware unrecognized */
1575         pr_err("Unrecognized vendor firmware descriptor\n");
1576
1577 success:
1578         kfree(buf);
1579         return true;
1580 }
1581
1582 static void dlfb_init_framebuffer_work(struct work_struct *work);
1583
1584 static int dlfb_usb_probe(struct usb_interface *interface,
1585                         const struct usb_device_id *id)
1586 {
1587         struct usb_device *usbdev;
1588         struct dlfb_data *dev = 0;
1589         int retval = -ENOMEM;
1590
1591         /* usb initialization */
1592
1593         usbdev = interface_to_usbdev(interface);
1594
1595         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1596         if (dev == NULL) {
1597                 err("dlfb_usb_probe: failed alloc of dev struct\n");
1598                 goto error;
1599         }
1600
1601         kref_init(&dev->kref); /* matching kref_put in usb .disconnect fn */
1602
1603         dev->udev = usbdev;
1604         dev->gdev = &usbdev->dev; /* our generic struct device * */
1605         usb_set_intfdata(interface, dev);
1606
1607         pr_info("%s %s - serial #%s\n",
1608                 usbdev->manufacturer, usbdev->product, usbdev->serial);
1609         pr_info("vid_%04x&pid_%04x&rev_%04x driver's dlfb_data struct at %p\n",
1610                 usbdev->descriptor.idVendor, usbdev->descriptor.idProduct,
1611                 usbdev->descriptor.bcdDevice, dev);
1612         pr_info("console enable=%d\n", console);
1613         pr_info("fb_defio enable=%d\n", fb_defio);
1614         pr_info("shadow enable=%d\n", shadow);
1615
1616         dev->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1617
1618         if (!dlfb_parse_vendor_descriptor(dev, interface)) {
1619                 pr_err("firmware not recognized. Assume incompatible device\n");
1620                 goto error;
1621         }
1622
1623         if (pixel_limit) {
1624                 pr_warn("DL chip limit of %d overriden"
1625                         " by module param to %d\n",
1626                         dev->sku_pixel_limit, pixel_limit);
1627                 dev->sku_pixel_limit = pixel_limit;
1628         }
1629
1630
1631         if (!dlfb_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1632                 retval = -ENOMEM;
1633                 pr_err("dlfb_alloc_urb_list failed\n");
1634                 goto error;
1635         }
1636
1637         kref_get(&dev->kref); /* matching kref_put in free_framebuffer_work */
1638
1639         /* We don't register a new USB class. Our client interface is fbdev */
1640
1641         /* Workitem keep things fast & simple during USB enumeration */
1642         INIT_DELAYED_WORK(&dev->init_framebuffer_work,
1643                           dlfb_init_framebuffer_work);
1644         schedule_delayed_work(&dev->init_framebuffer_work, 0);
1645
1646         return 0;
1647
1648 error:
1649         if (dev) {
1650
1651                 kref_put(&dev->kref, dlfb_free); /* ref for framebuffer */
1652                 kref_put(&dev->kref, dlfb_free); /* last ref from kref_init */
1653
1654                 /* dev has been deallocated. Do not dereference */
1655         }
1656
1657         return retval;
1658 }
1659
1660 static void dlfb_init_framebuffer_work(struct work_struct *work)
1661 {
1662         struct dlfb_data *dev = container_of(work, struct dlfb_data,
1663                                              init_framebuffer_work.work);
1664         struct fb_info *info;
1665         int retval;
1666         int i;
1667
1668         /* allocates framebuffer driver structure, not framebuffer memory */
1669         info = framebuffer_alloc(0, dev->gdev);
1670         if (!info) {
1671                 retval = -ENOMEM;
1672                 pr_err("framebuffer_alloc failed\n");
1673                 goto error;
1674         }
1675
1676         dev->info = info;
1677         info->par = dev;
1678         info->pseudo_palette = dev->pseudo_palette;
1679         info->fbops = &dlfb_ops;
1680
1681         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1682         if (retval < 0) {
1683                 pr_err("fb_alloc_cmap failed %x\n", retval);
1684                 goto error;
1685         }
1686
1687         INIT_DELAYED_WORK(&dev->free_framebuffer_work,
1688                           dlfb_free_framebuffer_work);
1689
1690         INIT_LIST_HEAD(&info->modelist);
1691
1692         retval = dlfb_setup_modes(dev, info, NULL, 0);
1693         if (retval != 0) {
1694                 pr_err("unable to find common mode for display and adapter\n");
1695                 goto error;
1696         }
1697
1698         /* ready to begin using device */
1699
1700         atomic_set(&dev->usb_active, 1);
1701         dlfb_select_std_channel(dev);
1702
1703         dlfb_ops_check_var(&info->var, info);
1704         dlfb_ops_set_par(info);
1705
1706         retval = register_framebuffer(info);
1707         if (retval < 0) {
1708                 pr_err("register_framebuffer failed %d\n", retval);
1709                 goto error;
1710         }
1711
1712         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1713                 retval = device_create_file(info->dev, &fb_device_attrs[i]);
1714                 if (retval) {
1715                         pr_warn("device_create_file failed %d\n", retval);
1716                 }
1717         }
1718
1719         retval = device_create_bin_file(info->dev, &edid_attr);
1720         if (retval) {
1721                 pr_warn("device_create_bin_file failed %d\n", retval);
1722         }
1723
1724         pr_info("DisplayLink USB device /dev/fb%d attached. %dx%d resolution."
1725                         " Using %dK framebuffer memory\n", info->node,
1726                         info->var.xres, info->var.yres,
1727                         ((dev->backing_buffer) ?
1728                         info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1729         return;
1730
1731 error:
1732         dlfb_free_framebuffer(dev);
1733 }
1734
1735 static void dlfb_usb_disconnect(struct usb_interface *interface)
1736 {
1737         struct dlfb_data *dev;
1738         struct fb_info *info;
1739         int i;
1740
1741         dev = usb_get_intfdata(interface);
1742         info = dev->info;
1743
1744         pr_info("USB disconnect starting\n");
1745
1746         /* we virtualize until all fb clients release. Then we free */
1747         dev->virtualized = true;
1748
1749         /* When non-active we'll update virtual framebuffer, but no new urbs */
1750         atomic_set(&dev->usb_active, 0);
1751
1752         /* this function will wait for all in-flight urbs to complete */
1753         dlfb_free_urb_list(dev);
1754
1755         if (info) {
1756                 /* remove udlfb's sysfs interfaces */
1757                 for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1758                         device_remove_file(info->dev, &fb_device_attrs[i]);
1759                 device_remove_bin_file(info->dev, &edid_attr);
1760                 unlink_framebuffer(info);
1761         }
1762
1763         usb_set_intfdata(interface, NULL);
1764         dev->udev = NULL;
1765         dev->gdev = NULL;
1766
1767         /* if clients still have us open, will be freed on last close */
1768         if (dev->fb_count == 0)
1769                 schedule_delayed_work(&dev->free_framebuffer_work, 0);
1770
1771         /* release reference taken by kref_init in probe() */
1772         kref_put(&dev->kref, dlfb_free);
1773
1774         /* consider dlfb_data freed */
1775
1776         return;
1777 }
1778
1779 static struct usb_driver dlfb_driver = {
1780         .name = "udlfb",
1781         .probe = dlfb_usb_probe,
1782         .disconnect = dlfb_usb_disconnect,
1783         .id_table = id_table,
1784 };
1785
1786 module_usb_driver(dlfb_driver);
1787
1788 static void dlfb_urb_completion(struct urb *urb)
1789 {
1790         struct urb_node *unode = urb->context;
1791         struct dlfb_data *dev = unode->dev;
1792         unsigned long flags;
1793
1794         /* sync/async unlink faults aren't errors */
1795         if (urb->status) {
1796                 if (!(urb->status == -ENOENT ||
1797                     urb->status == -ECONNRESET ||
1798                     urb->status == -ESHUTDOWN)) {
1799                         pr_err("%s - nonzero write bulk status received: %d\n",
1800                                 __func__, urb->status);
1801                         atomic_set(&dev->lost_pixels, 1);
1802                 }
1803         }
1804
1805         urb->transfer_buffer_length = dev->urbs.size; /* reset to actual */
1806
1807         spin_lock_irqsave(&dev->urbs.lock, flags);
1808         list_add_tail(&unode->entry, &dev->urbs.list);
1809         dev->urbs.available++;
1810         spin_unlock_irqrestore(&dev->urbs.lock, flags);
1811
1812         /*
1813          * When using fb_defio, we deadlock if up() is called
1814          * while another is waiting. So queue to another process.
1815          */
1816         if (fb_defio)
1817                 schedule_delayed_work(&unode->release_urb_work, 0);
1818         else
1819                 up(&dev->urbs.limit_sem);
1820 }
1821
1822 static void dlfb_free_urb_list(struct dlfb_data *dev)
1823 {
1824         int count = dev->urbs.count;
1825         struct list_head *node;
1826         struct urb_node *unode;
1827         struct urb *urb;
1828         int ret;
1829         unsigned long flags;
1830
1831         pr_notice("Freeing all render urbs\n");
1832
1833         /* keep waiting and freeing, until we've got 'em all */
1834         while (count--) {
1835
1836                 /* Getting interrupted means a leak, but ok at disconnect */
1837                 ret = down_interruptible(&dev->urbs.limit_sem);
1838                 if (ret)
1839                         break;
1840
1841                 spin_lock_irqsave(&dev->urbs.lock, flags);
1842
1843                 node = dev->urbs.list.next; /* have reserved one with sem */
1844                 list_del_init(node);
1845
1846                 spin_unlock_irqrestore(&dev->urbs.lock, flags);
1847
1848                 unode = list_entry(node, struct urb_node, entry);
1849                 urb = unode->urb;
1850
1851                 /* Free each separately allocated piece */
1852                 usb_free_coherent(urb->dev, dev->urbs.size,
1853                                   urb->transfer_buffer, urb->transfer_dma);
1854                 usb_free_urb(urb);
1855                 kfree(node);
1856         }
1857
1858         dev->urbs.count = 0;
1859 }
1860
1861 static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size)
1862 {
1863         int i = 0;
1864         struct urb *urb;
1865         struct urb_node *unode;
1866         char *buf;
1867
1868         spin_lock_init(&dev->urbs.lock);
1869
1870         dev->urbs.size = size;
1871         INIT_LIST_HEAD(&dev->urbs.list);
1872
1873         while (i < count) {
1874                 unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
1875                 if (!unode)
1876                         break;
1877                 unode->dev = dev;
1878
1879                 INIT_DELAYED_WORK(&unode->release_urb_work,
1880                           dlfb_release_urb_work);
1881
1882                 urb = usb_alloc_urb(0, GFP_KERNEL);
1883                 if (!urb) {
1884                         kfree(unode);
1885                         break;
1886                 }
1887                 unode->urb = urb;
1888
1889                 buf = usb_alloc_coherent(dev->udev, MAX_TRANSFER, GFP_KERNEL,
1890                                          &urb->transfer_dma);
1891                 if (!buf) {
1892                         kfree(unode);
1893                         usb_free_urb(urb);
1894                         break;
1895                 }
1896
1897                 /* urb->transfer_buffer_length set to actual before submit */
1898                 usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 1),
1899                         buf, size, dlfb_urb_completion, unode);
1900                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1901
1902                 list_add_tail(&unode->entry, &dev->urbs.list);
1903
1904                 i++;
1905         }
1906
1907         sema_init(&dev->urbs.limit_sem, i);
1908         dev->urbs.count = i;
1909         dev->urbs.available = i;
1910
1911         pr_notice("allocated %d %d byte urbs\n", i, (int) size);
1912
1913         return i;
1914 }
1915
1916 static struct urb *dlfb_get_urb(struct dlfb_data *dev)
1917 {
1918         int ret = 0;
1919         struct list_head *entry;
1920         struct urb_node *unode;
1921         struct urb *urb = NULL;
1922         unsigned long flags;
1923
1924         /* Wait for an in-flight buffer to complete and get re-queued */
1925         ret = down_timeout(&dev->urbs.limit_sem, GET_URB_TIMEOUT);
1926         if (ret) {
1927                 atomic_set(&dev->lost_pixels, 1);
1928                 pr_warn("wait for urb interrupted: %x available: %d\n",
1929                        ret, dev->urbs.available);
1930                 goto error;
1931         }
1932
1933         spin_lock_irqsave(&dev->urbs.lock, flags);
1934
1935         BUG_ON(list_empty(&dev->urbs.list)); /* reserved one with limit_sem */
1936         entry = dev->urbs.list.next;
1937         list_del_init(entry);
1938         dev->urbs.available--;
1939
1940         spin_unlock_irqrestore(&dev->urbs.lock, flags);
1941
1942         unode = list_entry(entry, struct urb_node, entry);
1943         urb = unode->urb;
1944
1945 error:
1946         return urb;
1947 }
1948
1949 static int dlfb_submit_urb(struct dlfb_data *dev, struct urb *urb, size_t len)
1950 {
1951         int ret;
1952
1953         BUG_ON(len > dev->urbs.size);
1954
1955         urb->transfer_buffer_length = len; /* set to actual payload len */
1956         ret = usb_submit_urb(urb, GFP_KERNEL);
1957         if (ret) {
1958                 dlfb_urb_completion(urb); /* because no one else will */
1959                 atomic_set(&dev->lost_pixels, 1);
1960                 pr_err("usb_submit_urb error %x\n", ret);
1961         }
1962         return ret;
1963 }
1964
1965 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1966 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1967
1968 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1969 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1970
1971 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1972 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1973
1974 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1975 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
1976
1977 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
1978               "Jaya Kumar <jayakumar.lkml@gmail.com>, "
1979               "Bernie Thompson <bernie@plugable.com>");
1980 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
1981 MODULE_LICENSE("GPL");
1982