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 (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 328                 return -EINVAL;
 329         if (size > info->fix.smem_len)
 330                 return -EINVAL;
 331         if (offset > info->fix.smem_len - size)
 332                 return -EINVAL;
 333
 334         pos = (unsigned long)info->fix.smem_start + offset;
 335
 336         pr_notice("mmap() framebuffer addr:%lu size:%lu\n",
 337                   pos, size);
 338
 339         while (size > 0) {
 340                 page = vmalloc_to_pfn((void *)pos);
 341                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 342                         return -EAGAIN;
 343
 344                 start += PAGE_SIZE;
 345                 pos += PAGE_SIZE;
 346                 if (size > PAGE_SIZE)
 347                         size -= PAGE_SIZE;
 348                 else
 349                         size = 0;
 350         }
 351
 352         return 0;
 353 }
 354
 355 /*
 356  * Trims identical data from front and back of line
 357  * Sets new front buffer address and width
 358  * And returns byte count of identical pixels
 359  * Assumes CPU natural alignment (unsigned long)
 360  * for back and front buffer ptrs and width
 361  */
 362 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 363 {
 364         int j, k;
 365         const unsigned long *back = (const unsigned long *) bback;
 366         const unsigned long *front = (const unsigned long *) *bfront;
 367         const int width = *width_bytes / sizeof(unsigned long);
 368         int identical = width;
 369         int start = width;
 370         int end = width;
 371
 372         prefetch((void *) front);
 373         prefetch((void *) back);
 374
 375         for (j = 0; j < width; j++) {
 376                 if (back[j] != front[j]) {
 377                         start = j;
 378                         break;
 379                 }
 380         }
 381
 382         for (k = width - 1; k > j; k--) {
 383                 if (back[k] != front[k]) {
 384                         end = k+1;
 385                         break;
 386                 }
 387         }
 388
 389         identical = start + (width - end);
 390         *bfront = (u8 *) &front[start];
 391         *width_bytes = (end - start) * sizeof(unsigned long);
 392
 393         return identical * sizeof(unsigned long);
 394 }
 395
 396 /*
 397  * Render a command stream for an encoded horizontal line segment of pixels.
 398  *
 399  * A command buffer holds several commands.
 400  * It always begins with a fresh command header
 401  * (the protocol doesn't require this, but we enforce it to allow
 402  * multiple buffers to be potentially encoded and sent in parallel).
 403  * A single command encodes one contiguous horizontal line of pixels
 404  *
 405  * The function relies on the client to do all allocation, so that
 406  * rendering can be done directly to output buffers (e.g. USB URBs).
 407  * The function fills the supplied command buffer, providing information
 408  * on where it left off, so the client may call in again with additional
 409  * buffers if the line will take several buffers to complete.
 410  *
 411  * A single command can transmit a maximum of 256 pixels,
 412  * regardless of the compression ratio (protocol design limit).
 413  * To the hardware, 0 for a size byte means 256
 414  *
 415  * Rather than 256 pixel commands which are either rl or raw encoded,
 416  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 417  * This has a slightly larger header overhead, but produces more even results.
 418  * It also processes all data (read and write) in a single pass.
 419  * Performance benchmarks of common cases show it having just slightly better
 420  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 421  * But for very rl friendly data, will compress not quite as well.
 422  */
 423 static void dlfb_compress_hline(
 424         const uint16_t **pixel_start_ptr,
 425         const uint16_t *const pixel_end,
 426         uint32_t *device_address_ptr,
 427         uint8_t **command_buffer_ptr,
 428         const uint8_t *const cmd_buffer_end)
 429 {
 430         const uint16_t *pixel = *pixel_start_ptr;
 431         uint32_t dev_addr  = *device_address_ptr;
 432         uint8_t *cmd = *command_buffer_ptr;
 433         const int bpp = 2;
 434
 435         while ((pixel_end > pixel) &&
 436                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 437                 uint8_t *raw_pixels_count_byte = 0;
 438                 uint8_t *cmd_pixels_count_byte = 0;
 439                 const uint16_t *raw_pixel_start = 0;
 440                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = 0;
 441
 442                 prefetchw((void *) cmd); /* pull in one cache line at least */
 443
 444                 *cmd++ = 0xAF;
 445                 *cmd++ = 0x6B;
 446                 *cmd++ = (uint8_t) ((dev_addr >> 16) & 0xFF);
 447                 *cmd++ = (uint8_t) ((dev_addr >> 8) & 0xFF);
 448                 *cmd++ = (uint8_t) ((dev_addr) & 0xFF);
 449
 450                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 451                 cmd_pixel_start = pixel;
 452
 453                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 454                 raw_pixel_start = pixel;
 455
 456                 cmd_pixel_end = pixel + min(MAX_CMD_PIXELS + 1,
 457                         min((int)(pixel_end - pixel),
 458                             (int)(cmd_buffer_end - cmd) / bpp));
 459
 460                 prefetch_range((void *) pixel, (cmd_pixel_end - pixel) * bpp);
 461
 462                 while (pixel < cmd_pixel_end) {
 463                         const uint16_t * const repeating_pixel = pixel;
 464
 465                         *(uint16_t *)cmd = cpu_to_be16p(pixel);
 466                         cmd += 2;
 467                         pixel++;
 468
 469                         if (unlikely((pixel < cmd_pixel_end) &&
 470                                      (*pixel == *repeating_pixel))) {
 471                                 /* go back and fill in raw pixel count */
 472                                 *raw_pixels_count_byte = ((repeating_pixel -
 473                                                 raw_pixel_start) + 1) & 0xFF;
 474
 475                                 while ((pixel < cmd_pixel_end)
 476                                        && (*pixel == *repeating_pixel)) {
 477                                         pixel++;
 478                                 }
 479
 480                                 /* immediately after raw data is repeat byte */
 481                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 482
 483                                 /* Then start another raw pixel span */
 484                                 raw_pixel_start = pixel;
 485                                 raw_pixels_count_byte = cmd++;
 486                         }
 487                 }
 488
 489                 if (pixel > raw_pixel_start) {
 490                         /* finalize last RAW span */
 491                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 492                 }
 493
 494                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 495                 dev_addr += (pixel - cmd_pixel_start) * bpp;
 496         }
 497
 498         if (cmd_buffer_end <= MIN_RLX_CMD_BYTES + cmd) {
 499                 /* Fill leftover bytes with no-ops */
 500                 if (cmd_buffer_end > cmd)
 501                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 502                 cmd = (uint8_t *) cmd_buffer_end;
 503         }
 504
 505         *command_buffer_ptr = cmd;
 506         *pixel_start_ptr = pixel;
 507         *device_address_ptr = dev_addr;
 508
 509         return;
 510 }
 511
 512 /*
 513  * There are 3 copies of every pixel: The front buffer that the fbdev
 514  * client renders to, the actual framebuffer across the USB bus in hardware
 515  * (that we can only write to, slowly, and can never read), and (optionally)
 516  * our shadow copy that tracks what's been sent to that hardware buffer.
 517  */
 518 static int dlfb_render_hline(struct dlfb_data *dev, struct urb **urb_ptr,
 519                               const char *front, char **urb_buf_ptr,
 520                               u32 byte_offset, u32 byte_width,
 521                               int *ident_ptr, int *sent_ptr)
 522 {
 523         const u8 *line_start, *line_end, *next_pixel;
 524         u32 dev_addr = dev->base16 + byte_offset;
 525         struct urb *urb = *urb_ptr;
 526         u8 *cmd = *urb_buf_ptr;
 527         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 528
 529         line_start = (u8 *) (front + byte_offset);
 530         next_pixel = line_start;
 531         line_end = next_pixel + byte_width;
 532
 533         if (dev->backing_buffer) {
 534                 int offset;
 535                 const u8 *back_start = (u8 *) (dev->backing_buffer
 536                                                 + byte_offset);
 537
 538                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 539                         &byte_width);
 540
 541                 offset = next_pixel - line_start;
 542                 line_end = next_pixel + byte_width;
 543                 dev_addr += offset;
 544                 back_start += offset;
 545                 line_start += offset;
 546
 547                 memcpy((char *)back_start, (char *) line_start,
 548                        byte_width);
 549         }
 550
 551         while (next_pixel < line_end) {
 552
 553                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 554                              (const uint16_t *) line_end, &dev_addr,
 555                         (u8 **) &cmd, (u8 *) cmd_end);
 556
 557                 if (cmd >= cmd_end) {
 558                         int len = cmd - (u8 *) urb->transfer_buffer;
 559                         if (dlfb_submit_urb(dev, urb, len))
 560                                 return 1; /* lost pixels is set */
 561                         *sent_ptr += len;
 562                         urb = dlfb_get_urb(dev);
 563                         if (!urb)
 564                                 return 1; /* lost_pixels is set */
 565                         *urb_ptr = urb;
 566                         cmd = urb->transfer_buffer;
 567                         cmd_end = &cmd[urb->transfer_buffer_length];
 568                 }
 569         }
 570
 571         *urb_buf_ptr = cmd;
 572
 573         return 0;
 574 }
 575
 576 int dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
 577                int width, int height, char *data)
 578 {
 579         int i, ret;
 580         char *cmd;
 581         cycles_t start_cycles, end_cycles;
 582         int bytes_sent = 0;
 583         int bytes_identical = 0;
 584         struct urb *urb;
 585         int aligned_x;
 586
 587         start_cycles = get_cycles();
 588
 589         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 590         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 591         x = aligned_x;
 592
 593         if ((width <= 0) ||
 594             (x + width > dev->info->var.xres) ||
 595             (y + height > dev->info->var.yres))
 596                 return -EINVAL;
 597
 598         if (!atomic_read(&dev->usb_active))
 599                 return 0;
 600
 601         urb = dlfb_get_urb(dev);
 602         if (!urb)
 603                 return 0;
 604         cmd = urb->transfer_buffer;
 605
 606         for (i = y; i < y + height ; i++) {
 607                 const int line_offset = dev->info->fix.line_length * i;
 608                 const int byte_offset = line_offset + (x * BPP);
 609
 610                 if (dlfb_render_hline(dev, &urb,
 611                                       (char *) dev->info->fix.smem_start,
 612                                       &cmd, byte_offset, width * BPP,
 613                                       &bytes_identical, &bytes_sent))
 614                         goto error;
 615         }
 616
 617         if (cmd > (char *) urb->transfer_buffer) {
 618                 /* Send partial buffer remaining before exiting */
 619                 int len = cmd - (char *) urb->transfer_buffer;
 620                 ret = dlfb_submit_urb(dev, urb, len);
 621                 bytes_sent += len;
 622         } else
 623                 dlfb_urb_completion(urb);
 624
 625 error:
 626         atomic_add(bytes_sent, &dev->bytes_sent);
 627         atomic_add(bytes_identical, &dev->bytes_identical);
 628         atomic_add(width*height*2, &dev->bytes_rendered);
 629         end_cycles = get_cycles();
 630         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 631                     >> 10)), /* Kcycles */
 632                    &dev->cpu_kcycles_used);
 633
 634         return 0;
 635 }
 636
 637 /*
 638  * Path triggered by usermode clients who write to filesystem
 639  * e.g. cat filename > /dev/fb1
 640  * Not used by X Windows or text-mode console. But useful for testing.
 641  * Slow because of extra copy and we must assume all pixels dirty.
 642  */
 643 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
 644                           size_t count, loff_t *ppos)
 645 {
 646         ssize_t result;
 647         struct dlfb_data *dev = info->par;
 648         u32 offset = (u32) *ppos;
 649
 650         result = fb_sys_write(info, buf, count, ppos);
 651
 652         if (result > 0) {
 653                 int start = max((int)(offset / info->fix.line_length), 0);
 654                 int lines = min((u32)((result / info->fix.line_length) + 1),
 655                                 (u32)info->var.yres);
 656
 657                 dlfb_handle_damage(dev, 0, start, info->var.xres,
 658                         lines, info->screen_base);
 659         }
 660
 661         return result;
 662 }
 663
 664 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 665 static void dlfb_ops_copyarea(struct fb_info *info,
 666                                 const struct fb_copyarea *area)
 667 {
 668
 669         struct dlfb_data *dev = info->par;
 670
 671         sys_copyarea(info, area);
 672
 673         dlfb_handle_damage(dev, area->dx, area->dy,
 674                         area->width, area->height, info->screen_base);
 675 }
 676
 677 static void dlfb_ops_imageblit(struct fb_info *info,
 678                                 const struct fb_image *image)
 679 {
 680         struct dlfb_data *dev = info->par;
 681
 682         sys_imageblit(info, image);
 683
 684         dlfb_handle_damage(dev, image->dx, image->dy,
 685                         image->width, image->height, info->screen_base);
 686 }
 687
 688 static void dlfb_ops_fillrect(struct fb_info *info,
 689                           const struct fb_fillrect *rect)
 690 {
 691         struct dlfb_data *dev = info->par;
 692
 693         sys_fillrect(info, rect);
 694
 695         dlfb_handle_damage(dev, rect->dx, rect->dy, rect->width,
 696                               rect->height, info->screen_base);
 697 }
 698
 699 /*
 700  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 701  *   Touching ANY framebuffer memory that triggers a page fault
 702  *   in fb_defio will cause a deadlock, when it also tries to
 703  *   grab the same mutex.
 704  */
 705 static void dlfb_dpy_deferred_io(struct fb_info *info,
 706                                 struct list_head *pagelist)
 707 {
 708         struct page *cur;
 709         struct fb_deferred_io *fbdefio = info->fbdefio;
 710         struct dlfb_data *dev = info->par;
 711         struct urb *urb;
 712         char *cmd;
 713         cycles_t start_cycles, end_cycles;
 714         int bytes_sent = 0;
 715         int bytes_identical = 0;
 716         int bytes_rendered = 0;
 717
 718         if (!fb_defio)
 719                 return;
 720
 721         if (!atomic_read(&dev->usb_active))
 722                 return;
 723
 724         start_cycles = get_cycles();
 725
 726         urb = dlfb_get_urb(dev);
 727         if (!urb)
 728                 return;
 729
 730         cmd = urb->transfer_buffer;
 731
 732         /* walk the written page list and render each to device */
 733         list_for_each_entry(cur, &fbdefio->pagelist, lru) {
 734
 735                 if (dlfb_render_hline(dev, &urb, (char *) info->fix.smem_start,
 736                                   &cmd, cur->index << PAGE_SHIFT,
 737                                   PAGE_SIZE, &bytes_identical, &bytes_sent))
 738                         goto error;
 739                 bytes_rendered += PAGE_SIZE;
 740         }
 741
 742         if (cmd > (char *) urb->transfer_buffer) {
 743                 /* Send partial buffer remaining before exiting */
 744                 int len = cmd - (char *) urb->transfer_buffer;
 745                 dlfb_submit_urb(dev, urb, len);
 746                 bytes_sent += len;
 747         } else
 748                 dlfb_urb_completion(urb);
 749
 750 error:
 751         atomic_add(bytes_sent, &dev->bytes_sent);
 752         atomic_add(bytes_identical, &dev->bytes_identical);
 753         atomic_add(bytes_rendered, &dev->bytes_rendered);
 754         end_cycles = get_cycles();
 755         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 756                     >> 10)), /* Kcycles */
 757                    &dev->cpu_kcycles_used);
 758 }
 759
 760 static int dlfb_get_edid(struct dlfb_data *dev, char *edid, int len)
 761 {
 762         int i;
 763         int ret;
 764         char *rbuf;
 765
 766         rbuf = kmalloc(2, GFP_KERNEL);
 767         if (!rbuf)
 768                 return 0;
 769
 770         for (i = 0; i < len; i++) {
 771                 ret = usb_control_msg(dev->udev,
 772                                     usb_rcvctrlpipe(dev->udev, 0), (0x02),
 773                                     (0x80 | (0x02 << 5)), i << 8, 0xA1, rbuf, 2,
 774                                     HZ);
 775                 if (ret < 1) {
 776                         pr_err("Read EDID byte %d failed err %x\n", i, ret);
 777                         i--;
 778                         break;
 779                 }
 780                 edid[i] = rbuf[1];
 781         }
 782
 783         kfree(rbuf);
 784
 785         return i;
 786 }
 787
 788 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
 789                                 unsigned long arg)
 790 {
 791
 792         struct dlfb_data *dev = info->par;
 793
 794         if (!atomic_read(&dev->usb_active))
 795                 return 0;
 796
 797         /* TODO: Update X server to get this from sysfs instead */
 798         if (cmd == DLFB_IOCTL_RETURN_EDID) {
 799                 void __user *edid = (void __user *)arg;
 800                 if (copy_to_user(edid, dev->edid, dev->edid_size))
 801                         return -EFAULT;
 802                 return 0;
 803         }
 804
 805         /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
 806         if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
 807                 struct dloarea area;
 808
 809                 if (copy_from_user(&area, (void __user *)arg,
 810                                   sizeof(struct dloarea)))
 811                         return -EFAULT;
 812
 813                 /*
 814                  * If we have a damage-aware client, turn fb_defio "off"
 815                  * To avoid perf imact of unnecessary page fault handling.
 816                  * Done by resetting the delay for this fb_info to a very
 817                  * long period. Pages will become writable and stay that way.
 818                  * Reset to normal value when all clients have closed this fb.
 819                  */
 820                 if (info->fbdefio)
 821                         info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 822
 823                 if (area.x < 0)
 824                         area.x = 0;
 825
 826                 if (area.x > info->var.xres)
 827                         area.x = info->var.xres;
 828
 829                 if (area.y < 0)
 830                         area.y = 0;
 831
 832                 if (area.y > info->var.yres)
 833                         area.y = info->var.yres;
 834
 835                 dlfb_handle_damage(dev, area.x, area.y, area.w, area.h,
 836                            info->screen_base);
 837         }
 838
 839         return 0;
 840 }
 841
 842 /* taken from vesafb */
 843 static int
 844 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
 845                unsigned blue, unsigned transp, struct fb_info *info)
 846 {
 847         int err = 0;
 848
 849         if (regno >= info->cmap.len)
 850                 return 1;
 851
 852         if (regno < 16) {
 853                 if (info->var.red.offset == 10) {
 854                         /* 1:5:5:5 */
 855                         ((u32 *) (info->pseudo_palette))[regno] =
 856                             ((red & 0xf800) >> 1) |
 857                             ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
 858                 } else {
 859                         /* 0:5:6:5 */
 860                         ((u32 *) (info->pseudo_palette))[regno] =
 861                             ((red & 0xf800)) |
 862                             ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
 863                 }
 864         }
 865
 866         return err;
 867 }
 868
 869 /*
 870  * It's common for several clients to have framebuffer open simultaneously.
 871  * e.g. both fbcon and X. Makes things interesting.
 872  * Assumes caller is holding info->lock (for open and release at least)
 873  */
 874 static int dlfb_ops_open(struct fb_info *info, int user)
 875 {
 876         struct dlfb_data *dev = info->par;
 877
 878         /*
 879          * fbcon aggressively connects to first framebuffer it finds,
 880          * preventing other clients (X) from working properly. Usually
 881          * not what the user wants. Fail by default with option to enable.
 882          */
 883         if ((user == 0) && (!console))
 884                 return -EBUSY;
 885
 886         /* If the USB device is gone, we don't accept new opens */
 887         if (dev->virtualized)
 888                 return -ENODEV;
 889
 890         dev->fb_count++;
 891
 892         kref_get(&dev->kref);
 893
 894         if (fb_defio && (info->fbdefio == NULL)) {
 895                 /* enable defio at last moment if not disabled by client */
 896
 897                 struct fb_deferred_io *fbdefio;
 898
 899                 fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 900
 901                 if (fbdefio) {
 902                         fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 903                         fbdefio->deferred_io = dlfb_dpy_deferred_io;
 904                 }
 905
 906                 info->fbdefio = fbdefio;
 907                 fb_deferred_io_init(info);
 908         }
 909
 910         pr_notice("open /dev/fb%d user=%d fb_info=%p count=%d\n",
 911             info->node, user, info, dev->fb_count);
 912
 913         return 0;
 914 }
 915
 916 /*
 917  * Called when all client interfaces to start transactions have been disabled,
 918  * and all references to our device instance (dlfb_data) are released.
 919  * Every transaction must have a reference, so we know are fully spun down
 920  */
 921 static void dlfb_free(struct kref *kref)
 922 {
 923         struct dlfb_data *dev = container_of(kref, struct dlfb_data, kref);
 924
 925         if (dev->backing_buffer)
 926                 vfree(dev->backing_buffer);
 927
 928         kfree(dev->edid);
 929
 930         pr_warn("freeing dlfb_data %p\n", dev);
 931
 932         kfree(dev);
 933 }
 934
 935 static void dlfb_release_urb_work(struct work_struct *work)
 936 {
 937         struct urb_node *unode = container_of(work, struct urb_node,
 938                                               release_urb_work.work);
 939
 940         up(&unode->dev->urbs.limit_sem);
 941 }
 942
 943 static void dlfb_free_framebuffer(struct dlfb_data *dev)
 944 {
 945         struct fb_info *info = dev->info;
 946
 947         if (info) {
 948                 int node = info->node;
 949
 950                 unregister_framebuffer(info);
 951
 952                 if (info->cmap.len != 0)
 953                         fb_dealloc_cmap(&info->cmap);
 954                 if (info->monspecs.modedb)
 955                         fb_destroy_modedb(info->monspecs.modedb);
 956                 if (info->screen_base)
 957                         vfree(info->screen_base);
 958
 959                 fb_destroy_modelist(&info->modelist);
 960
 961                 dev->info = NULL;
 962
 963                 /* Assume info structure is freed after this point */
 964                 framebuffer_release(info);
 965
 966                 pr_warn("fb_info for /dev/fb%d has been freed\n", node);
 967         }
 968
 969         /* ref taken in probe() as part of registering framebfufer */
 970         kref_put(&dev->kref, dlfb_free);
 971 }
 972
 973 static void dlfb_free_framebuffer_work(struct work_struct *work)
 974 {
 975         struct dlfb_data *dev = container_of(work, struct dlfb_data,
 976                                              free_framebuffer_work.work);
 977         dlfb_free_framebuffer(dev);
 978 }
 979 /*
 980  * Assumes caller is holding info->lock mutex (for open and release at least)
 981  */
 982 static int dlfb_ops_release(struct fb_info *info, int user)
 983 {
 984         struct dlfb_data *dev = info->par;
 985
 986         dev->fb_count--;
 987
 988         /* We can't free fb_info here - fbmem will touch it when we return */
 989         if (dev->virtualized && (dev->fb_count == 0))
 990                 schedule_delayed_work(&dev->free_framebuffer_work, HZ);
 991
 992         if ((dev->fb_count == 0) && (info->fbdefio)) {
 993                 fb_deferred_io_cleanup(info);
 994                 kfree(info->fbdefio);
 995                 info->fbdefio = NULL;
 996                 info->fbops->fb_mmap = dlfb_ops_mmap;
 997         }
 998
 999         pr_warn("released /dev/fb%d user=%d count=%d\n",
1000                   info->node, user, dev->fb_count);
1001
1002         kref_put(&dev->kref, dlfb_free);
1003
1004         return 0;
1005 }
1006
1007 /*
1008  * Check whether a video mode is supported by the DisplayLink chip
1009  * We start from monitor's modes, so don't need to filter that here
1010  */
1011 static int dlfb_is_valid_mode(struct fb_videomode *mode,
1012                 struct fb_info *info)
1013 {
1014         struct dlfb_data *dev = info->par;
1015
1016         if (mode->xres * mode->yres > dev->sku_pixel_limit) {
1017                 pr_warn("%dx%d beyond chip capabilities\n",
1018                        mode->xres, mode->yres);
1019                 return 0;
1020         }
1021
1022         pr_info("%dx%d @ %d Hz valid mode\n", mode->xres, mode->yres,
1023                 mode->refresh);
1024
1025         return 1;
1026 }
1027
1028 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1029 {
1030         const struct fb_bitfield red = { 11, 5, 0 };
1031         const struct fb_bitfield green = { 5, 6, 0 };
1032         const struct fb_bitfield blue = { 0, 5, 0 };
1033
1034         var->bits_per_pixel = 16;
1035         var->red = red;
1036         var->green = green;
1037         var->blue = blue;
1038 }
1039
1040 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1041                                 struct fb_info *info)
1042 {
1043         struct fb_videomode mode;
1044
1045         /* TODO: support dynamically changing framebuffer size */
1046         if ((var->xres * var->yres * 2) > info->fix.smem_len)
1047                 return -EINVAL;
1048
1049         /* set device-specific elements of var unrelated to mode */
1050         dlfb_var_color_format(var);
1051
1052         fb_var_to_videomode(&mode, var);
1053
1054         if (!dlfb_is_valid_mode(&mode, info))
1055                 return -EINVAL;
1056
1057         return 0;
1058 }
1059
1060 static int dlfb_ops_set_par(struct fb_info *info)
1061 {
1062         struct dlfb_data *dev = info->par;
1063         int result;
1064         u16 *pix_framebuffer;
1065         int i;
1066
1067         pr_notice("set_par mode %dx%d\n", info->var.xres, info->var.yres);
1068
1069         result = dlfb_set_video_mode(dev, &info->var);
1070
1071         if ((result == 0) && (dev->fb_count == 0)) {
1072
1073                 /* paint greenscreen */
1074
1075                 pix_framebuffer = (u16 *) info->screen_base;
1076                 for (i = 0; i < info->fix.smem_len / 2; i++)
1077                         pix_framebuffer[i] = 0x37e6;
1078
1079                 dlfb_handle_damage(dev, 0, 0, info->var.xres, info->var.yres,
1080                                    info->screen_base);
1081         }
1082
1083         return result;
1084 }
1085
1086 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1087 static char *dlfb_dummy_render(char *buf)
1088 {
1089         *buf++ = 0xAF;
1090         *buf++ = 0x6A; /* copy */
1091         *buf++ = 0x00; /* from address*/
1092         *buf++ = 0x00;
1093         *buf++ = 0x00;
1094         *buf++ = 0x01; /* one pixel */
1095         *buf++ = 0x00; /* to address */
1096         *buf++ = 0x00;
1097         *buf++ = 0x00;
1098         return buf;
1099 }
1100
1101 /*
1102  * In order to come back from full DPMS off, we need to set the mode again
1103  */
1104 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1105 {
1106         struct dlfb_data *dev = info->par;
1107         char *bufptr;
1108         struct urb *urb;
1109
1110         pr_info("/dev/fb%d FB_BLANK mode %d --> %d\n",
1111                 info->node, dev->blank_mode, blank_mode);
1112
1113         if ((dev->blank_mode == FB_BLANK_POWERDOWN) &&
1114             (blank_mode != FB_BLANK_POWERDOWN)) {
1115
1116                 /* returning from powerdown requires a fresh modeset */
1117                 dlfb_set_video_mode(dev, &info->var);
1118         }
1119
1120         urb = dlfb_get_urb(dev);
1121         if (!urb)
1122                 return 0;
1123
1124         bufptr = (char *) urb->transfer_buffer;
1125         bufptr = dlfb_vidreg_lock(bufptr);
1126         bufptr = dlfb_blanking(bufptr, blank_mode);
1127         bufptr = dlfb_vidreg_unlock(bufptr);
1128
1129         /* seems like a render op is needed to have blank change take effect */
1130         bufptr = dlfb_dummy_render(bufptr);
1131
1132         dlfb_submit_urb(dev, urb, bufptr -
1133                         (char *) urb->transfer_buffer);
1134
1135         dev->blank_mode = blank_mode;
1136
1137         return 0;
1138 }
1139
1140 static struct fb_ops dlfb_ops = {
1141         .owner = THIS_MODULE,
1142         .fb_read = fb_sys_read,
1143         .fb_write = dlfb_ops_write,
1144         .fb_setcolreg = dlfb_ops_setcolreg,
1145         .fb_fillrect = dlfb_ops_fillrect,
1146         .fb_copyarea = dlfb_ops_copyarea,
1147         .fb_imageblit = dlfb_ops_imageblit,
1148         .fb_mmap = dlfb_ops_mmap,
1149         .fb_ioctl = dlfb_ops_ioctl,
1150         .fb_open = dlfb_ops_open,
1151         .fb_release = dlfb_ops_release,
1152         .fb_blank = dlfb_ops_blank,
1153         .fb_check_var = dlfb_ops_check_var,
1154         .fb_set_par = dlfb_ops_set_par,
1155 };
1156
1157
1158 /*
1159  * Assumes &info->lock held by caller
1160  * Assumes no active clients have framebuffer open
1161  */
1162 static int dlfb_realloc_framebuffer(struct dlfb_data *dev, struct fb_info *info)
1163 {
1164         int retval = -ENOMEM;
1165         int old_len = info->fix.smem_len;
1166         int new_len;
1167         unsigned char *old_fb = info->screen_base;
1168         unsigned char *new_fb;
1169         unsigned char *new_back = 0;
1170
1171         pr_warn("Reallocating framebuffer. Addresses will change!\n");
1172
1173         new_len = info->fix.line_length * info->var.yres;
1174
1175         if (PAGE_ALIGN(new_len) > old_len) {
1176                 /*
1177                  * Alloc system memory for virtual framebuffer
1178                  */
1179                 new_fb = vmalloc(new_len);
1180                 if (!new_fb) {
1181                         pr_err("Virtual framebuffer alloc failed\n");
1182                         goto error;
1183                 }
1184
1185                 if (info->screen_base) {
1186                         memcpy(new_fb, old_fb, old_len);
1187                         vfree(info->screen_base);
1188                 }
1189
1190                 info->screen_base = new_fb;
1191                 info->fix.smem_len = PAGE_ALIGN(new_len);
1192                 info->fix.smem_start = (unsigned long) new_fb;
1193                 info->flags = udlfb_info_flags;
1194
1195                 /*
1196                  * Second framebuffer copy to mirror the framebuffer state
1197                  * on the physical USB device. We can function without this.
1198                  * But with imperfect damage info we may send pixels over USB
1199                  * that were, in fact, unchanged - wasting limited USB bandwidth
1200                  */
1201                 if (shadow)
1202                         new_back = vzalloc(new_len);
1203                 if (!new_back)
1204                         pr_info("No shadow/backing buffer allocated\n");
1205                 else {
1206                         if (dev->backing_buffer)
1207                                 vfree(dev->backing_buffer);
1208                         dev->backing_buffer = new_back;
1209                 }
1210         }
1211
1212         retval = 0;
1213
1214 error:
1215         return retval;
1216 }
1217
1218 /*
1219  * 1) Get EDID from hw, or use sw default
1220  * 2) Parse into various fb_info structs
1221  * 3) Allocate virtual framebuffer memory to back highest res mode
1222  *
1223  * Parses EDID into three places used by various parts of fbdev:
1224  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1225  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1226  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1227  *
1228  * If EDID is not readable/valid, then modelist is all VESA modes,
1229  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1230  * Returns 0 if successful
1231  */
1232 static int dlfb_setup_modes(struct dlfb_data *dev,
1233                            struct fb_info *info,
1234                            char *default_edid, size_t default_edid_size)
1235 {
1236         int i;
1237         const struct fb_videomode *default_vmode = NULL;
1238         int result = 0;
1239         char *edid;
1240         int tries = 3;
1241
1242         if (info->dev) /* only use mutex if info has been registered */
1243                 mutex_lock(&info->lock);
1244
1245         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1246         if (!edid) {
1247                 result = -ENOMEM;
1248                 goto error;
1249         }
1250
1251         fb_destroy_modelist(&info->modelist);
1252         memset(&info->monspecs, 0, sizeof(info->monspecs));
1253
1254         /*
1255          * Try to (re)read EDID from hardware first
1256          * EDID data may return, but not parse as valid
1257          * Try again a few times, in case of e.g. analog cable noise
1258          */
1259         while (tries--) {
1260
1261                 i = dlfb_get_edid(dev, edid, EDID_LENGTH);
1262
1263                 if (i >= EDID_LENGTH)
1264                         fb_edid_to_monspecs(edid, &info->monspecs);
1265
1266                 if (info->monspecs.modedb_len > 0) {
1267                         dev->edid = edid;
1268                         dev->edid_size = i;
1269                         break;
1270                 }
1271         }
1272
1273         /* If that fails, use a previously returned EDID if available */
1274         if (info->monspecs.modedb_len == 0) {
1275
1276                 pr_err("Unable to get valid EDID from device/display\n");
1277
1278                 if (dev->edid) {
1279                         fb_edid_to_monspecs(dev->edid, &info->monspecs);
1280                         if (info->monspecs.modedb_len > 0)
1281                                 pr_err("Using previously queried EDID\n");
1282                 }
1283         }
1284
1285         /* If that fails, use the default EDID we were handed */
1286         if (info->monspecs.modedb_len == 0) {
1287                 if (default_edid_size >= EDID_LENGTH) {
1288                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1289                         if (info->monspecs.modedb_len > 0) {
1290                                 memcpy(edid, default_edid, default_edid_size);
1291                                 dev->edid = edid;
1292                                 dev->edid_size = default_edid_size;
1293                                 pr_err("Using default/backup EDID\n");
1294                         }
1295                 }
1296         }
1297
1298         /* If we've got modes, let's pick a best default mode */
1299         if (info->monspecs.modedb_len > 0) {
1300
1301                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1302                         if (dlfb_is_valid_mode(&info->monspecs.modedb[i], info))
1303                                 fb_add_videomode(&info->monspecs.modedb[i],
1304                                         &info->modelist);
1305                         else {
1306                                 if (i == 0)
1307                                         /* if we've removed top/best mode */
1308                                         info->monspecs.misc
1309                                                 &= ~FB_MISC_1ST_DETAIL;
1310                         }
1311                 }
1312
1313                 default_vmode = fb_find_best_display(&info->monspecs,
1314                                                      &info->modelist);
1315         }
1316
1317         /* If everything else has failed, fall back to safe default mode */
1318         if (default_vmode == NULL) {
1319
1320                 struct fb_videomode fb_vmode = {0};
1321
1322                 /*
1323                  * Add the standard VESA modes to our modelist
1324                  * Since we don't have EDID, there may be modes that
1325                  * overspec monitor and/or are incorrect aspect ratio, etc.
1326                  * But at least the user has a chance to choose
1327                  */
1328                 for (i = 0; i < VESA_MODEDB_SIZE; i++) {
1329                         if (dlfb_is_valid_mode((struct fb_videomode *)
1330                                                 &vesa_modes[i], info))
1331                                 fb_add_videomode(&vesa_modes[i],
1332                                                  &info->modelist);
1333                 }
1334
1335                 /*
1336                  * default to resolution safe for projectors
1337                  * (since they are most common case without EDID)
1338                  */
1339                 fb_vmode.xres = 800;
1340                 fb_vmode.yres = 600;
1341                 fb_vmode.refresh = 60;
1342                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1343                                                      &info->modelist);
1344         }
1345
1346         /* If we have good mode and no active clients*/
1347         if ((default_vmode != NULL) && (dev->fb_count == 0)) {
1348
1349                 fb_videomode_to_var(&info->var, default_vmode);
1350                 dlfb_var_color_format(&info->var);
1351
1352                 /*
1353                  * with mode size info, we can now alloc our framebuffer.
1354                  */
1355                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1356                 info->fix.line_length = info->var.xres *
1357                         (info->var.bits_per_pixel / 8);
1358
1359                 result = dlfb_realloc_framebuffer(dev, info);
1360
1361         } else
1362                 result = -EINVAL;
1363
1364 error:
1365         if (edid && (dev->edid != edid))
1366                 kfree(edid);
1367
1368         if (info->dev)
1369                 mutex_unlock(&info->lock);
1370
1371         return result;
1372 }
1373
1374 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1375                                    struct device_attribute *a, char *buf) {
1376         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1377         struct dlfb_data *dev = fb_info->par;
1378         return snprintf(buf, PAGE_SIZE, "%u\n",
1379                         atomic_read(&dev->bytes_rendered));
1380 }
1381
1382 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1383                                    struct device_attribute *a, char *buf) {
1384         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1385         struct dlfb_data *dev = fb_info->par;
1386         return snprintf(buf, PAGE_SIZE, "%u\n",
1387                         atomic_read(&dev->bytes_identical));
1388 }
1389
1390 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1391                                    struct device_attribute *a, char *buf) {
1392         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1393         struct dlfb_data *dev = fb_info->par;
1394         return snprintf(buf, PAGE_SIZE, "%u\n",
1395                         atomic_read(&dev->bytes_sent));
1396 }
1397
1398 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1399                                    struct device_attribute *a, char *buf) {
1400         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1401         struct dlfb_data *dev = fb_info->par;
1402         return snprintf(buf, PAGE_SIZE, "%u\n",
1403                         atomic_read(&dev->cpu_kcycles_used));
1404 }
1405
1406 static ssize_t edid_show(
1407                         struct file *filp,
1408                         struct kobject *kobj, struct bin_attribute *a,
1409                          char *buf, loff_t off, size_t count) {
1410         struct device *fbdev = container_of(kobj, struct device, kobj);
1411         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1412         struct dlfb_data *dev = fb_info->par;
1413
1414         if (dev->edid == NULL)
1415                 return 0;
1416
1417         if ((off >= dev->edid_size) || (count > dev->edid_size))
1418                 return 0;
1419
1420         if (off + count > dev->edid_size)
1421                 count = dev->edid_size - off;
1422
1423         pr_info("sysfs edid copy %p to %p, %d bytes\n",
1424                 dev->edid, buf, (int) count);
1425
1426         memcpy(buf, dev->edid, count);
1427
1428         return count;
1429 }
1430
1431 static ssize_t edid_store(
1432                         struct file *filp,
1433                         struct kobject *kobj, struct bin_attribute *a,
1434                         char *src, loff_t src_off, size_t src_size) {
1435         struct device *fbdev = container_of(kobj, struct device, kobj);
1436         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1437         struct dlfb_data *dev = fb_info->par;
1438         int ret;
1439
1440         /* We only support write of entire EDID at once, no offset*/
1441         if ((src_size != EDID_LENGTH) || (src_off != 0))
1442                 return -EINVAL;
1443
1444         ret = dlfb_setup_modes(dev, fb_info, src, src_size);
1445         if (ret)
1446                 return ret;
1447
1448         if (!dev->edid || memcmp(src, dev->edid, src_size))
1449                 return -EINVAL;
1450
1451         pr_info("sysfs written EDID is new default\n");
1452         dlfb_ops_set_par(fb_info);
1453         return src_size;
1454 }
1455
1456 static ssize_t metrics_reset_store(struct device *fbdev,
1457                            struct device_attribute *attr,
1458                            const char *buf, size_t count)
1459 {
1460         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1461         struct dlfb_data *dev = fb_info->par;
1462
1463         atomic_set(&dev->bytes_rendered, 0);
1464         atomic_set(&dev->bytes_identical, 0);
1465         atomic_set(&dev->bytes_sent, 0);
1466         atomic_set(&dev->cpu_kcycles_used, 0);
1467
1468         return count;
1469 }
1470
1471 static struct bin_attribute edid_attr = {
1472         .attr.name = "edid",
1473         .attr.mode = 0666,
1474         .size = EDID_LENGTH,
1475         .read = edid_show,
1476         .write = edid_store
1477 };
1478
1479 static struct device_attribute fb_device_attrs[] = {
1480         __ATTR_RO(metrics_bytes_rendered),
1481         __ATTR_RO(metrics_bytes_identical),
1482         __ATTR_RO(metrics_bytes_sent),
1483         __ATTR_RO(metrics_cpu_kcycles_used),
1484         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1485 };
1486
1487 /*
1488  * This is necessary before we can communicate with the display controller.
1489  */
1490 static int dlfb_select_std_channel(struct dlfb_data *dev)
1491 {
1492         int ret;
1493         u8 set_def_chn[] = {       0x57, 0xCD, 0xDC, 0xA7,
1494                                 0x1C, 0x88, 0x5E, 0x15,
1495                                 0x60, 0xFE, 0xC6, 0x97,
1496                                 0x16, 0x3D, 0x47, 0xF2  };
1497
1498         ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
1499                         NR_USB_REQUEST_CHANNEL,
1500                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1501                         set_def_chn, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
1502         return ret;
1503 }
1504
1505 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dev,
1506                                         struct usb_interface *interface)
1507 {
1508         char *desc;
1509         char *buf;
1510         char *desc_end;
1511
1512         int total_len = 0;
1513
1514         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1515         if (!buf)
1516                 return false;
1517         desc = buf;
1518
1519         total_len = usb_get_descriptor(interface_to_usbdev(interface),
1520                                         0x5f, /* vendor specific */
1521                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1522
1523         /* if not found, look in configuration descriptor */
1524         if (total_len < 0) {
1525                 if (0 == usb_get_extra_descriptor(interface->cur_altsetting,
1526                         0x5f, &desc))
1527                         total_len = (int) desc[0];
1528         }
1529
1530         if (total_len > 5) {
1531                 pr_info("vendor descriptor length:%x data:%02x %02x %02x %02x" \
1532                         "%02x %02x %02x %02x %02x %02x %02x\n",
1533                         total_len, desc[0],
1534                         desc[1], desc[2], desc[3], desc[4], desc[5], desc[6],
1535                         desc[7], desc[8], desc[9], desc[10]);
1536
1537                 if ((desc[0] != total_len) || /* descriptor length */
1538                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1539                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1540                     (desc[3] != 0x00) ||
1541                     (desc[4] != total_len - 2)) /* length after type */
1542                         goto unrecognized;
1543
1544                 desc_end = desc + total_len;
1545                 desc += 5; /* the fixed header we've already parsed */
1546
1547                 while (desc < desc_end) {
1548                         u8 length;
1549                         u16 key;
1550
1551                         key = le16_to_cpu(*((u16 *) desc));
1552                         desc += sizeof(u16);
1553                         length = *desc;
1554                         desc++;
1555
1556                         switch (key) {
1557                         case 0x0200: { /* max_area */
1558                                 u32 max_area;
1559                                 max_area = le32_to_cpu(*((u32 *)desc));
1560                                 pr_warn("DL chip limited to %d pixel modes\n",
1561                                         max_area);
1562                                 dev->sku_pixel_limit = max_area;
1563                                 break;
1564                         }
1565                         default:
1566                                 break;
1567                         }
1568                         desc += length;
1569                 }
1570         } else {
1571                 pr_info("vendor descriptor not available (%d)\n", total_len);
1572         }
1573
1574         goto success;
1575
1576 unrecognized:
1577         /* allow udlfb to load for now even if firmware unrecognized */
1578         pr_err("Unrecognized vendor firmware descriptor\n");
1579
1580 success:
1581         kfree(buf);
1582         return true;
1583 }
1584
1585 static void dlfb_init_framebuffer_work(struct work_struct *work);
1586
1587 static int dlfb_usb_probe(struct usb_interface *interface,
1588                         const struct usb_device_id *id)
1589 {
1590         struct usb_device *usbdev;
1591         struct dlfb_data *dev = 0;
1592         int retval = -ENOMEM;
1593
1594         /* usb initialization */
1595
1596         usbdev = interface_to_usbdev(interface);
1597
1598         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1599         if (dev == NULL) {
1600                 dev_err(&interface->dev, "dlfb_usb_probe: failed alloc of dev struct\n");
1601                 goto error;
1602         }
1603
1604         kref_init(&dev->kref); /* matching kref_put in usb .disconnect fn */
1605
1606         dev->udev = usbdev;
1607         dev->gdev = &usbdev->dev; /* our generic struct device * */
1608         usb_set_intfdata(interface, dev);
1609
1610         pr_info("%s %s - serial #%s\n",
1611                 usbdev->manufacturer, usbdev->product, usbdev->serial);
1612         pr_info("vid_%04x&pid_%04x&rev_%04x driver's dlfb_data struct at %p\n",
1613                 usbdev->descriptor.idVendor, usbdev->descriptor.idProduct,
1614                 usbdev->descriptor.bcdDevice, dev);
1615         pr_info("console enable=%d\n", console);
1616         pr_info("fb_defio enable=%d\n", fb_defio);
1617         pr_info("shadow enable=%d\n", shadow);
1618
1619         dev->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1620
1621         if (!dlfb_parse_vendor_descriptor(dev, interface)) {
1622                 pr_err("firmware not recognized. Assume incompatible device\n");
1623                 goto error;
1624         }
1625
1626         if (pixel_limit) {
1627                 pr_warn("DL chip limit of %d overriden"
1628                         " by module param to %d\n",
1629                         dev->sku_pixel_limit, pixel_limit);
1630                 dev->sku_pixel_limit = pixel_limit;
1631         }
1632
1633
1634         if (!dlfb_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1635                 retval = -ENOMEM;
1636                 pr_err("dlfb_alloc_urb_list failed\n");
1637                 goto error;
1638         }
1639
1640         kref_get(&dev->kref); /* matching kref_put in free_framebuffer_work */
1641
1642         /* We don't register a new USB class. Our client interface is fbdev */
1643
1644         /* Workitem keep things fast & simple during USB enumeration */
1645         INIT_DELAYED_WORK(&dev->init_framebuffer_work,
1646                           dlfb_init_framebuffer_work);
1647         schedule_delayed_work(&dev->init_framebuffer_work, 0);
1648
1649         return 0;
1650
1651 error:
1652         if (dev) {
1653
1654                 kref_put(&dev->kref, dlfb_free); /* ref for framebuffer */
1655                 kref_put(&dev->kref, dlfb_free); /* last ref from kref_init */
1656
1657                 /* dev has been deallocated. Do not dereference */
1658         }
1659
1660         return retval;
1661 }
1662
1663 static void dlfb_init_framebuffer_work(struct work_struct *work)
1664 {
1665         struct dlfb_data *dev = container_of(work, struct dlfb_data,
1666                                              init_framebuffer_work.work);
1667         struct fb_info *info;
1668         int retval;
1669         int i;
1670
1671         /* allocates framebuffer driver structure, not framebuffer memory */
1672         info = framebuffer_alloc(0, dev->gdev);
1673         if (!info) {
1674                 retval = -ENOMEM;
1675                 pr_err("framebuffer_alloc failed\n");
1676                 goto error;
1677         }
1678
1679         dev->info = info;
1680         info->par = dev;
1681         info->pseudo_palette = dev->pseudo_palette;
1682         info->fbops = &dlfb_ops;
1683
1684         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1685         if (retval < 0) {
1686                 pr_err("fb_alloc_cmap failed %x\n", retval);
1687                 goto error;
1688         }
1689
1690         INIT_DELAYED_WORK(&dev->free_framebuffer_work,
1691                           dlfb_free_framebuffer_work);
1692
1693         INIT_LIST_HEAD(&info->modelist);
1694
1695         retval = dlfb_setup_modes(dev, info, NULL, 0);
1696         if (retval != 0) {
1697                 pr_err("unable to find common mode for display and adapter\n");
1698                 goto error;
1699         }
1700
1701         /* ready to begin using device */
1702
1703         atomic_set(&dev->usb_active, 1);
1704         dlfb_select_std_channel(dev);
1705
1706         dlfb_ops_check_var(&info->var, info);
1707         dlfb_ops_set_par(info);
1708
1709         retval = register_framebuffer(info);
1710         if (retval < 0) {
1711                 pr_err("register_framebuffer failed %d\n", retval);
1712                 goto error;
1713         }
1714
1715         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1716                 retval = device_create_file(info->dev, &fb_device_attrs[i]);
1717                 if (retval) {
1718                         pr_warn("device_create_file failed %d\n", retval);
1719                 }
1720         }
1721
1722         retval = device_create_bin_file(info->dev, &edid_attr);
1723         if (retval) {
1724                 pr_warn("device_create_bin_file failed %d\n", retval);
1725         }
1726
1727         pr_info("DisplayLink USB device /dev/fb%d attached. %dx%d resolution."
1728                         " Using %dK framebuffer memory\n", info->node,
1729                         info->var.xres, info->var.yres,
1730                         ((dev->backing_buffer) ?
1731                         info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1732         return;
1733
1734 error:
1735         dlfb_free_framebuffer(dev);
1736 }
1737
1738 static void dlfb_usb_disconnect(struct usb_interface *interface)
1739 {
1740         struct dlfb_data *dev;
1741         struct fb_info *info;
1742         int i;
1743
1744         dev = usb_get_intfdata(interface);
1745         info = dev->info;
1746
1747         pr_info("USB disconnect starting\n");
1748
1749         /* we virtualize until all fb clients release. Then we free */
1750         dev->virtualized = true;
1751
1752         /* When non-active we'll update virtual framebuffer, but no new urbs */
1753         atomic_set(&dev->usb_active, 0);
1754
1755         /* this function will wait for all in-flight urbs to complete */
1756         dlfb_free_urb_list(dev);
1757
1758         if (info) {
1759                 /* remove udlfb's sysfs interfaces */
1760                 for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1761                         device_remove_file(info->dev, &fb_device_attrs[i]);
1762                 device_remove_bin_file(info->dev, &edid_attr);
1763                 unlink_framebuffer(info);
1764         }
1765
1766         usb_set_intfdata(interface, NULL);
1767         dev->udev = NULL;
1768         dev->gdev = NULL;
1769
1770         /* if clients still have us open, will be freed on last close */
1771         if (dev->fb_count == 0)
1772                 schedule_delayed_work(&dev->free_framebuffer_work, 0);
1773
1774         /* release reference taken by kref_init in probe() */
1775         kref_put(&dev->kref, dlfb_free);
1776
1777         /* consider dlfb_data freed */
1778
1779         return;
1780 }
1781
1782 static struct usb_driver dlfb_driver = {
1783         .name = "udlfb",
1784         .probe = dlfb_usb_probe,
1785         .disconnect = dlfb_usb_disconnect,
1786         .id_table = id_table,
1787 };
1788
1789 module_usb_driver(dlfb_driver);
1790
1791 static void dlfb_urb_completion(struct urb *urb)
1792 {
1793         struct urb_node *unode = urb->context;
1794         struct dlfb_data *dev = unode->dev;
1795         unsigned long flags;
1796
1797         /* sync/async unlink faults aren't errors */
1798         if (urb->status) {
1799                 if (!(urb->status == -ENOENT ||
1800                     urb->status == -ECONNRESET ||
1801                     urb->status == -ESHUTDOWN)) {
1802                         pr_err("%s - nonzero write bulk status received: %d\n",
1803                                 __func__, urb->status);
1804                         atomic_set(&dev->lost_pixels, 1);
1805                 }
1806         }
1807
1808         urb->transfer_buffer_length = dev->urbs.size; /* reset to actual */
1809
1810         spin_lock_irqsave(&dev->urbs.lock, flags);
1811         list_add_tail(&unode->entry, &dev->urbs.list);
1812         dev->urbs.available++;
1813         spin_unlock_irqrestore(&dev->urbs.lock, flags);
1814
1815         /*
1816          * When using fb_defio, we deadlock if up() is called
1817          * while another is waiting. So queue to another process.
1818          */
1819         if (fb_defio)
1820                 schedule_delayed_work(&unode->release_urb_work, 0);
1821         else
1822                 up(&dev->urbs.limit_sem);
1823 }
1824
1825 static void dlfb_free_urb_list(struct dlfb_data *dev)
1826 {
1827         int count = dev->urbs.count;
1828         struct list_head *node;
1829         struct urb_node *unode;
1830         struct urb *urb;
1831         int ret;
1832         unsigned long flags;
1833
1834         pr_notice("Freeing all render urbs\n");
1835
1836         /* keep waiting and freeing, until we've got 'em all */
1837         while (count--) {
1838
1839                 /* Getting interrupted means a leak, but ok at disconnect */
1840                 ret = down_interruptible(&dev->urbs.limit_sem);
1841                 if (ret)
1842                         break;
1843
1844                 spin_lock_irqsave(&dev->urbs.lock, flags);
1845
1846                 node = dev->urbs.list.next; /* have reserved one with sem */
1847                 list_del_init(node);
1848
1849                 spin_unlock_irqrestore(&dev->urbs.lock, flags);
1850
1851                 unode = list_entry(node, struct urb_node, entry);
1852                 urb = unode->urb;
1853
1854                 /* Free each separately allocated piece */
1855                 usb_free_coherent(urb->dev, dev->urbs.size,
1856                                   urb->transfer_buffer, urb->transfer_dma);
1857                 usb_free_urb(urb);
1858                 kfree(node);
1859         }
1860
1861         dev->urbs.count = 0;
1862 }
1863
1864 static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size)
1865 {
1866         int i = 0;
1867         struct urb *urb;
1868         struct urb_node *unode;
1869         char *buf;
1870
1871         spin_lock_init(&dev->urbs.lock);
1872
1873         dev->urbs.size = size;
1874         INIT_LIST_HEAD(&dev->urbs.list);
1875
1876         while (i < count) {
1877                 unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
1878                 if (!unode)
1879                         break;
1880                 unode->dev = dev;
1881
1882                 INIT_DELAYED_WORK(&unode->release_urb_work,
1883                           dlfb_release_urb_work);
1884
1885                 urb = usb_alloc_urb(0, GFP_KERNEL);
1886                 if (!urb) {
1887                         kfree(unode);
1888                         break;
1889                 }
1890                 unode->urb = urb;
1891
1892                 buf = usb_alloc_coherent(dev->udev, MAX_TRANSFER, GFP_KERNEL,
1893                                          &urb->transfer_dma);
1894                 if (!buf) {
1895                         kfree(unode);
1896                         usb_free_urb(urb);
1897                         break;
1898                 }
1899
1900                 /* urb->transfer_buffer_length set to actual before submit */
1901                 usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 1),
1902                         buf, size, dlfb_urb_completion, unode);
1903                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1904
1905                 list_add_tail(&unode->entry, &dev->urbs.list);
1906
1907                 i++;
1908         }
1909
1910         sema_init(&dev->urbs.limit_sem, i);
1911         dev->urbs.count = i;
1912         dev->urbs.available = i;
1913
1914         pr_notice("allocated %d %d byte urbs\n", i, (int) size);
1915
1916         return i;
1917 }
1918
1919 static struct urb *dlfb_get_urb(struct dlfb_data *dev)
1920 {
1921         int ret = 0;
1922         struct list_head *entry;
1923         struct urb_node *unode;
1924         struct urb *urb = NULL;
1925         unsigned long flags;
1926
1927         /* Wait for an in-flight buffer to complete and get re-queued */
1928         ret = down_timeout(&dev->urbs.limit_sem, GET_URB_TIMEOUT);
1929         if (ret) {
1930                 atomic_set(&dev->lost_pixels, 1);
1931                 pr_warn("wait for urb interrupted: %x available: %d\n",
1932                        ret, dev->urbs.available);
1933                 goto error;
1934         }
1935
1936         spin_lock_irqsave(&dev->urbs.lock, flags);
1937
1938         BUG_ON(list_empty(&dev->urbs.list)); /* reserved one with limit_sem */
1939         entry = dev->urbs.list.next;
1940         list_del_init(entry);
1941         dev->urbs.available--;
1942
1943         spin_unlock_irqrestore(&dev->urbs.lock, flags);
1944
1945         unode = list_entry(entry, struct urb_node, entry);
1946         urb = unode->urb;
1947
1948 error:
1949         return urb;
1950 }
1951
1952 static int dlfb_submit_urb(struct dlfb_data *dev, struct urb *urb, size_t len)
1953 {
1954         int ret;
1955
1956         BUG_ON(len > dev->urbs.size);
1957
1958         urb->transfer_buffer_length = len; /* set to actual payload len */
1959         ret = usb_submit_urb(urb, GFP_KERNEL);
1960         if (ret) {
1961                 dlfb_urb_completion(urb); /* because no one else will */
1962                 atomic_set(&dev->lost_pixels, 1);
1963                 pr_err("usb_submit_urb error %x\n", ret);
1964         }
1965         return ret;
1966 }
1967
1968 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1969 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1970
1971 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1972 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1973
1974 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1975 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1976
1977 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1978 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
1979
1980 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
1981               "Jaya Kumar <jayakumar.lkml@gmail.com>, "
1982               "Bernie Thompson <bernie@plugable.com>");
1983 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
1984 MODULE_LICENSE("GPL");
1985