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