drivers/video/fbdev/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 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/init.h>
  22 #include <linux/usb.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/mm.h>
  25 #include <linux/fb.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/slab.h>
  28 #include <linux/delay.h>
  29 #include <asm/unaligned.h>
  30 #include <video/udlfb.h>
  31 #include "edid.h"
  32
  33 static const struct fb_fix_screeninfo dlfb_fix = {
  34         .id =           "udlfb",
  35         .type =         FB_TYPE_PACKED_PIXELS,
  36         .visual =       FB_VISUAL_TRUECOLOR,
  37         .xpanstep =     0,
  38         .ypanstep =     0,
  39         .ywrapstep =    0,
  40         .accel =        FB_ACCEL_NONE,
  41 };
  42
  43 static const u32 udlfb_info_flags = FBINFO_DEFAULT | FBINFO_READS_FAST |
  44                 FBINFO_VIRTFB |
  45                 FBINFO_HWACCEL_IMAGEBLIT | FBINFO_HWACCEL_FILLRECT |
  46                 FBINFO_HWACCEL_COPYAREA | FBINFO_MISC_ALWAYS_SETPAR;
  47
  48 /*
  49  * There are many DisplayLink-based graphics products, all with unique PIDs.
  50  * So we match on DisplayLink's VID + Vendor-Defined Interface Class (0xff)
  51  * We also require a match on SubClass (0x00) and Protocol (0x00),
  52  * which is compatible with all known USB 2.0 era graphics chips and firmware,
  53  * but allows DisplayLink to increment those for any future incompatible chips
  54  */
  55 static const struct usb_device_id id_table[] = {
  56         {.idVendor = 0x17e9,
  57          .bInterfaceClass = 0xff,
  58          .bInterfaceSubClass = 0x00,
  59          .bInterfaceProtocol = 0x00,
  60          .match_flags = USB_DEVICE_ID_MATCH_VENDOR |
  61                 USB_DEVICE_ID_MATCH_INT_CLASS |
  62                 USB_DEVICE_ID_MATCH_INT_SUBCLASS |
  63                 USB_DEVICE_ID_MATCH_INT_PROTOCOL,
  64         },
  65         {},
  66 };
  67 MODULE_DEVICE_TABLE(usb, id_table);
  68
  69 /* module options */
  70 static bool console = 1; /* Allow fbcon to open framebuffer */
  71 static bool fb_defio = 1;  /* Detect mmap writes using page faults */
  72 static bool shadow = 1; /* Optionally disable shadow framebuffer */
  73 static int pixel_limit; /* Optionally force a pixel resolution limit */
  74
  75 struct dlfb_deferred_free {
  76         struct list_head list;
  77         void *mem;
  78 };
  79
  80 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len);
  81
  82 /* dlfb keeps a list of urbs for efficient bulk transfers */
  83 static void dlfb_urb_completion(struct urb *urb);
  84 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb);
  85 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb * urb, size_t len);
  86 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size);
  87 static void dlfb_free_urb_list(struct dlfb_data *dlfb);
  88
  89 /*
  90  * All DisplayLink bulk operations start with 0xAF, followed by specific code
  91  * All operations are written to buffers which then later get sent to device
  92  */
  93 static char *dlfb_set_register(char *buf, u8 reg, u8 val)
  94 {
  95         *buf++ = 0xAF;
  96         *buf++ = 0x20;
  97         *buf++ = reg;
  98         *buf++ = val;
  99         return buf;
 100 }
 101
 102 static char *dlfb_vidreg_lock(char *buf)
 103 {
 104         return dlfb_set_register(buf, 0xFF, 0x00);
 105 }
 106
 107 static char *dlfb_vidreg_unlock(char *buf)
 108 {
 109         return dlfb_set_register(buf, 0xFF, 0xFF);
 110 }
 111
 112 /*
 113  * Map FB_BLANK_* to DisplayLink register
 114  * DLReg FB_BLANK_*
 115  * ----- -----------------------------
 116  *  0x00 FB_BLANK_UNBLANK (0)
 117  *  0x01 FB_BLANK (1)
 118  *  0x03 FB_BLANK_VSYNC_SUSPEND (2)
 119  *  0x05 FB_BLANK_HSYNC_SUSPEND (3)
 120  *  0x07 FB_BLANK_POWERDOWN (4) Note: requires modeset to come back
 121  */
 122 static char *dlfb_blanking(char *buf, int fb_blank)
 123 {
 124         u8 reg;
 125
 126         switch (fb_blank) {
 127         case FB_BLANK_POWERDOWN:
 128                 reg = 0x07;
 129                 break;
 130         case FB_BLANK_HSYNC_SUSPEND:
 131                 reg = 0x05;
 132                 break;
 133         case FB_BLANK_VSYNC_SUSPEND:
 134                 reg = 0x03;
 135                 break;
 136         case FB_BLANK_NORMAL:
 137                 reg = 0x01;
 138                 break;
 139         default:
 140                 reg = 0x00;
 141         }
 142
 143         buf = dlfb_set_register(buf, 0x1F, reg);
 144
 145         return buf;
 146 }
 147
 148 static char *dlfb_set_color_depth(char *buf, u8 selection)
 149 {
 150         return dlfb_set_register(buf, 0x00, selection);
 151 }
 152
 153 static char *dlfb_set_base16bpp(char *wrptr, u32 base)
 154 {
 155         /* the base pointer is 16 bits wide, 0x20 is hi byte. */
 156         wrptr = dlfb_set_register(wrptr, 0x20, base >> 16);
 157         wrptr = dlfb_set_register(wrptr, 0x21, base >> 8);
 158         return dlfb_set_register(wrptr, 0x22, base);
 159 }
 160
 161 /*
 162  * DisplayLink HW has separate 16bpp and 8bpp framebuffers.
 163  * In 24bpp modes, the low 323 RGB bits go in the 8bpp framebuffer
 164  */
 165 static char *dlfb_set_base8bpp(char *wrptr, u32 base)
 166 {
 167         wrptr = dlfb_set_register(wrptr, 0x26, base >> 16);
 168         wrptr = dlfb_set_register(wrptr, 0x27, base >> 8);
 169         return dlfb_set_register(wrptr, 0x28, base);
 170 }
 171
 172 static char *dlfb_set_register_16(char *wrptr, u8 reg, u16 value)
 173 {
 174         wrptr = dlfb_set_register(wrptr, reg, value >> 8);
 175         return dlfb_set_register(wrptr, reg+1, value);
 176 }
 177
 178 /*
 179  * This is kind of weird because the controller takes some
 180  * register values in a different byte order than other registers.
 181  */
 182 static char *dlfb_set_register_16be(char *wrptr, u8 reg, u16 value)
 183 {
 184         wrptr = dlfb_set_register(wrptr, reg, value);
 185         return dlfb_set_register(wrptr, reg+1, value >> 8);
 186 }
 187
 188 /*
 189  * LFSR is linear feedback shift register. The reason we have this is
 190  * because the display controller needs to minimize the clock depth of
 191  * various counters used in the display path. So this code reverses the
 192  * provided value into the lfsr16 value by counting backwards to get
 193  * the value that needs to be set in the hardware comparator to get the
 194  * same actual count. This makes sense once you read above a couple of
 195  * times and think about it from a hardware perspective.
 196  */
 197 static u16 dlfb_lfsr16(u16 actual_count)
 198 {
 199         u32 lv = 0xFFFF; /* This is the lfsr value that the hw starts with */
 200
 201         while (actual_count--) {
 202                 lv =     ((lv << 1) |
 203                         (((lv >> 15) ^ (lv >> 4) ^ (lv >> 2) ^ (lv >> 1)) & 1))
 204                         & 0xFFFF;
 205         }
 206
 207         return (u16) lv;
 208 }
 209
 210 /*
 211  * This does LFSR conversion on the value that is to be written.
 212  * See LFSR explanation above for more detail.
 213  */
 214 static char *dlfb_set_register_lfsr16(char *wrptr, u8 reg, u16 value)
 215 {
 216         return dlfb_set_register_16(wrptr, reg, dlfb_lfsr16(value));
 217 }
 218
 219 /*
 220  * This takes a standard fbdev screeninfo struct and all of its monitor mode
 221  * details and converts them into the DisplayLink equivalent register commands.
 222  */
 223 static char *dlfb_set_vid_cmds(char *wrptr, struct fb_var_screeninfo *var)
 224 {
 225         u16 xds, yds;
 226         u16 xde, yde;
 227         u16 yec;
 228
 229         /* x display start */
 230         xds = var->left_margin + var->hsync_len;
 231         wrptr = dlfb_set_register_lfsr16(wrptr, 0x01, xds);
 232         /* x display end */
 233         xde = xds + var->xres;
 234         wrptr = dlfb_set_register_lfsr16(wrptr, 0x03, xde);
 235
 236         /* y display start */
 237         yds = var->upper_margin + var->vsync_len;
 238         wrptr = dlfb_set_register_lfsr16(wrptr, 0x05, yds);
 239         /* y display end */
 240         yde = yds + var->yres;
 241         wrptr = dlfb_set_register_lfsr16(wrptr, 0x07, yde);
 242
 243         /* x end count is active + blanking - 1 */
 244         wrptr = dlfb_set_register_lfsr16(wrptr, 0x09,
 245                         xde + var->right_margin - 1);
 246
 247         /* libdlo hardcodes hsync start to 1 */
 248         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0B, 1);
 249
 250         /* hsync end is width of sync pulse + 1 */
 251         wrptr = dlfb_set_register_lfsr16(wrptr, 0x0D, var->hsync_len + 1);
 252
 253         /* hpixels is active pixels */
 254         wrptr = dlfb_set_register_16(wrptr, 0x0F, var->xres);
 255
 256         /* yendcount is vertical active + vertical blanking */
 257         yec = var->yres + var->upper_margin + var->lower_margin +
 258                         var->vsync_len;
 259         wrptr = dlfb_set_register_lfsr16(wrptr, 0x11, yec);
 260
 261         /* libdlo hardcodes vsync start to 0 */
 262         wrptr = dlfb_set_register_lfsr16(wrptr, 0x13, 0);
 263
 264         /* vsync end is width of vsync pulse */
 265         wrptr = dlfb_set_register_lfsr16(wrptr, 0x15, var->vsync_len);
 266
 267         /* vpixels is active pixels */
 268         wrptr = dlfb_set_register_16(wrptr, 0x17, var->yres);
 269
 270         /* convert picoseconds to 5kHz multiple for pclk5k = x * 1E12/5k */
 271         wrptr = dlfb_set_register_16be(wrptr, 0x1B,
 272                         200*1000*1000/var->pixclock);
 273
 274         return wrptr;
 275 }
 276
 277 /*
 278  * This takes a standard fbdev screeninfo struct that was fetched or prepared
 279  * and then generates the appropriate command sequence that then drives the
 280  * display controller.
 281  */
 282 static int dlfb_set_video_mode(struct dlfb_data *dlfb,
 283                                 struct fb_var_screeninfo *var)
 284 {
 285         char *buf;
 286         char *wrptr;
 287         int retval;
 288         int writesize;
 289         struct urb *urb;
 290
 291         if (!atomic_read(&dlfb->usb_active))
 292                 return -EPERM;
 293
 294         urb = dlfb_get_urb(dlfb);
 295         if (!urb)
 296                 return -ENOMEM;
 297
 298         buf = (char *) urb->transfer_buffer;
 299
 300         /*
 301         * This first section has to do with setting the base address on the
 302         * controller * associated with the display. There are 2 base
 303         * pointers, currently, we only * use the 16 bpp segment.
 304         */
 305         wrptr = dlfb_vidreg_lock(buf);
 306         wrptr = dlfb_set_color_depth(wrptr, 0x00);
 307         /* set base for 16bpp segment to 0 */
 308         wrptr = dlfb_set_base16bpp(wrptr, 0);
 309         /* set base for 8bpp segment to end of fb */
 310         wrptr = dlfb_set_base8bpp(wrptr, dlfb->info->fix.smem_len);
 311
 312         wrptr = dlfb_set_vid_cmds(wrptr, var);
 313         wrptr = dlfb_blanking(wrptr, FB_BLANK_UNBLANK);
 314         wrptr = dlfb_vidreg_unlock(wrptr);
 315
 316         writesize = wrptr - buf;
 317
 318         retval = dlfb_submit_urb(dlfb, urb, writesize);
 319
 320         dlfb->blank_mode = FB_BLANK_UNBLANK;
 321
 322         return retval;
 323 }
 324
 325 static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 326 {
 327         unsigned long start = vma->vm_start;
 328         unsigned long size = vma->vm_end - vma->vm_start;
 329         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 330         unsigned long page, pos;
 331
 332         if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
 333                 return -EINVAL;
 334         if (size > info->fix.smem_len)
 335                 return -EINVAL;
 336         if (offset > info->fix.smem_len - size)
 337                 return -EINVAL;
 338
 339         pos = (unsigned long)info->fix.smem_start + offset;
 340
 341         dev_dbg(info->dev, "mmap() framebuffer addr:%lu size:%lu\n",
 342                 pos, size);
 343
 344         while (size > 0) {
 345                 page = vmalloc_to_pfn((void *)pos);
 346                 if (remap_pfn_range(vma, start, page, PAGE_SIZE, PAGE_SHARED))
 347                         return -EAGAIN;
 348
 349                 start += PAGE_SIZE;
 350                 pos += PAGE_SIZE;
 351                 if (size > PAGE_SIZE)
 352                         size -= PAGE_SIZE;
 353                 else
 354                         size = 0;
 355         }
 356
 357         return 0;
 358 }
 359
 360 /*
 361  * Trims identical data from front and back of line
 362  * Sets new front buffer address and width
 363  * And returns byte count of identical pixels
 364  * Assumes CPU natural alignment (unsigned long)
 365  * for back and front buffer ptrs and width
 366  */
 367 static int dlfb_trim_hline(const u8 *bback, const u8 **bfront, int *width_bytes)
 368 {
 369         int j, k;
 370         const unsigned long *back = (const unsigned long *) bback;
 371         const unsigned long *front = (const unsigned long *) *bfront;
 372         const int width = *width_bytes / sizeof(unsigned long);
 373         int identical = width;
 374         int start = width;
 375         int end = width;
 376
 377         for (j = 0; j < width; j++) {
 378                 if (back[j] != front[j]) {
 379                         start = j;
 380                         break;
 381                 }
 382         }
 383
 384         for (k = width - 1; k > j; k--) {
 385                 if (back[k] != front[k]) {
 386                         end = k+1;
 387                         break;
 388                 }
 389         }
 390
 391         identical = start + (width - end);
 392         *bfront = (u8 *) &front[start];
 393         *width_bytes = (end - start) * sizeof(unsigned long);
 394
 395         return identical * sizeof(unsigned long);
 396 }
 397
 398 /*
 399  * Render a command stream for an encoded horizontal line segment of pixels.
 400  *
 401  * A command buffer holds several commands.
 402  * It always begins with a fresh command header
 403  * (the protocol doesn't require this, but we enforce it to allow
 404  * multiple buffers to be potentially encoded and sent in parallel).
 405  * A single command encodes one contiguous horizontal line of pixels
 406  *
 407  * The function relies on the client to do all allocation, so that
 408  * rendering can be done directly to output buffers (e.g. USB URBs).
 409  * The function fills the supplied command buffer, providing information
 410  * on where it left off, so the client may call in again with additional
 411  * buffers if the line will take several buffers to complete.
 412  *
 413  * A single command can transmit a maximum of 256 pixels,
 414  * regardless of the compression ratio (protocol design limit).
 415  * To the hardware, 0 for a size byte means 256
 416  *
 417  * Rather than 256 pixel commands which are either rl or raw encoded,
 418  * the rlx command simply assumes alternating raw and rl spans within one cmd.
 419  * This has a slightly larger header overhead, but produces more even results.
 420  * It also processes all data (read and write) in a single pass.
 421  * Performance benchmarks of common cases show it having just slightly better
 422  * compression than 256 pixel raw or rle commands, with similar CPU consumpion.
 423  * But for very rl friendly data, will compress not quite as well.
 424  */
 425 static void dlfb_compress_hline(
 426         const uint16_t **pixel_start_ptr,
 427         const uint16_t *const pixel_end,
 428         uint32_t *device_address_ptr,
 429         uint8_t **command_buffer_ptr,
 430         const uint8_t *const cmd_buffer_end,
 431         unsigned long back_buffer_offset,
 432         int *ident_ptr)
 433 {
 434         const uint16_t *pixel = *pixel_start_ptr;
 435         uint32_t dev_addr  = *device_address_ptr;
 436         uint8_t *cmd = *command_buffer_ptr;
 437
 438         while ((pixel_end > pixel) &&
 439                (cmd_buffer_end - MIN_RLX_CMD_BYTES > cmd)) {
 440                 uint8_t *raw_pixels_count_byte = NULL;
 441                 uint8_t *cmd_pixels_count_byte = NULL;
 442                 const uint16_t *raw_pixel_start = NULL;
 443                 const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 444
 445                 if (back_buffer_offset &&
 446                     *pixel == *(u16 *)((u8 *)pixel + back_buffer_offset)) {
 447                         pixel++;
 448                         dev_addr += BPP;
 449                         (*ident_ptr)++;
 450                         continue;
 451                 }
 452
 453                 *cmd++ = 0xAF;
 454                 *cmd++ = 0x6B;
 455                 *cmd++ = dev_addr >> 16;
 456                 *cmd++ = dev_addr >> 8;
 457                 *cmd++ = dev_addr;
 458
 459                 cmd_pixels_count_byte = cmd++; /*  we'll know this later */
 460                 cmd_pixel_start = pixel;
 461
 462                 raw_pixels_count_byte = cmd++; /*  we'll know this later */
 463                 raw_pixel_start = pixel;
 464
 465                 cmd_pixel_end = pixel + min3(MAX_CMD_PIXELS + 1UL,
 466                                         (unsigned long)(pixel_end - pixel),
 467                                         (unsigned long)(cmd_buffer_end - 1 - cmd) / BPP);
 468
 469                 if (back_buffer_offset) {
 470                         /* note: the framebuffer may change under us, so we must test for underflow */
 471                         while (cmd_pixel_end - 1 > pixel &&
 472                                *(cmd_pixel_end - 1) == *(u16 *)((u8 *)(cmd_pixel_end - 1) + back_buffer_offset))
 473                                 cmd_pixel_end--;
 474                 }
 475
 476                 while (pixel < cmd_pixel_end) {
 477                         const uint16_t * const repeating_pixel = pixel;
 478                         u16 pixel_value = *pixel;
 479
 480                         put_unaligned_be16(pixel_value, cmd);
 481                         if (back_buffer_offset)
 482                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 483                         cmd += 2;
 484                         pixel++;
 485
 486                         if (unlikely((pixel < cmd_pixel_end) &&
 487                                      (*pixel == pixel_value))) {
 488                                 /* go back and fill in raw pixel count */
 489                                 *raw_pixels_count_byte = ((repeating_pixel -
 490                                                 raw_pixel_start) + 1) & 0xFF;
 491
 492                                 do {
 493                                         if (back_buffer_offset)
 494                                                 *(u16 *)((u8 *)pixel + back_buffer_offset) = pixel_value;
 495                                         pixel++;
 496                                 } while ((pixel < cmd_pixel_end) &&
 497                                          (*pixel == pixel_value));
 498
 499                                 /* immediately after raw data is repeat byte */
 500                                 *cmd++ = ((pixel - repeating_pixel) - 1) & 0xFF;
 501
 502                                 /* Then start another raw pixel span */
 503                                 raw_pixel_start = pixel;
 504                                 raw_pixels_count_byte = cmd++;
 505                         }
 506                 }
 507
 508                 if (pixel > raw_pixel_start) {
 509                         /* finalize last RAW span */
 510                         *raw_pixels_count_byte = (pixel-raw_pixel_start) & 0xFF;
 511                 } else {
 512                         /* undo unused byte */
 513                         cmd--;
 514                 }
 515
 516                 *cmd_pixels_count_byte = (pixel - cmd_pixel_start) & 0xFF;
 517                 dev_addr += (u8 *)pixel - (u8 *)cmd_pixel_start;
 518         }
 519
 520         if (cmd_buffer_end - MIN_RLX_CMD_BYTES <= cmd) {
 521                 /* Fill leftover bytes with no-ops */
 522                 if (cmd_buffer_end > cmd)
 523                         memset(cmd, 0xAF, cmd_buffer_end - cmd);
 524                 cmd = (uint8_t *) cmd_buffer_end;
 525         }
 526
 527         *command_buffer_ptr = cmd;
 528         *pixel_start_ptr = pixel;
 529         *device_address_ptr = dev_addr;
 530 }
 531
 532 /*
 533  * There are 3 copies of every pixel: The front buffer that the fbdev
 534  * client renders to, the actual framebuffer across the USB bus in hardware
 535  * (that we can only write to, slowly, and can never read), and (optionally)
 536  * our shadow copy that tracks what's been sent to that hardware buffer.
 537  */
 538 static int dlfb_render_hline(struct dlfb_data *dlfb, struct urb **urb_ptr,
 539                               const char *front, char **urb_buf_ptr,
 540                               u32 byte_offset, u32 byte_width,
 541                               int *ident_ptr, int *sent_ptr)
 542 {
 543         const u8 *line_start, *line_end, *next_pixel;
 544         u32 dev_addr = dlfb->base16 + byte_offset;
 545         struct urb *urb = *urb_ptr;
 546         u8 *cmd = *urb_buf_ptr;
 547         u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 548         unsigned long back_buffer_offset = 0;
 549
 550         line_start = (u8 *) (front + byte_offset);
 551         next_pixel = line_start;
 552         line_end = next_pixel + byte_width;
 553
 554         if (dlfb->backing_buffer) {
 555                 int offset;
 556                 const u8 *back_start = (u8 *) (dlfb->backing_buffer
 557                                                 + byte_offset);
 558
 559                 back_buffer_offset = (unsigned long)back_start - (unsigned long)line_start;
 560
 561                 *ident_ptr += dlfb_trim_hline(back_start, &next_pixel,
 562                         &byte_width);
 563
 564                 offset = next_pixel - line_start;
 565                 line_end = next_pixel + byte_width;
 566                 dev_addr += offset;
 567                 back_start += offset;
 568                 line_start += offset;
 569         }
 570
 571         while (next_pixel < line_end) {
 572
 573                 dlfb_compress_hline((const uint16_t **) &next_pixel,
 574                              (const uint16_t *) line_end, &dev_addr,
 575                         (u8 **) &cmd, (u8 *) cmd_end, back_buffer_offset,
 576                         ident_ptr);
 577
 578                 if (cmd >= cmd_end) {
 579                         int len = cmd - (u8 *) urb->transfer_buffer;
 580                         if (dlfb_submit_urb(dlfb, urb, len))
 581                                 return 1; /* lost pixels is set */
 582                         *sent_ptr += len;
 583                         urb = dlfb_get_urb(dlfb);
 584                         if (!urb)
 585                                 return 1; /* lost_pixels is set */
 586                         *urb_ptr = urb;
 587                         cmd = urb->transfer_buffer;
 588                         cmd_end = &cmd[urb->transfer_buffer_length];
 589                 }
 590         }
 591
 592         *urb_buf_ptr = cmd;
 593
 594         return 0;
 595 }
 596
 597 static int dlfb_handle_damage(struct dlfb_data *dlfb, int x, int y,
 598                int width, int height, char *data)
 599 {
 600         int i, ret;
 601         char *cmd;
 602         cycles_t start_cycles, end_cycles;
 603         int bytes_sent = 0;
 604         int bytes_identical = 0;
 605         struct urb *urb;
 606         int aligned_x;
 607
 608         start_cycles = get_cycles();
 609
 610         aligned_x = DL_ALIGN_DOWN(x, sizeof(unsigned long));
 611         width = DL_ALIGN_UP(width + (x-aligned_x), sizeof(unsigned long));
 612         x = aligned_x;
 613
 614         if ((width <= 0) ||
 615             (x + width > dlfb->info->var.xres) ||
 616             (y + height > dlfb->info->var.yres))
 617                 return -EINVAL;
 618
 619         if (!atomic_read(&dlfb->usb_active))
 620                 return 0;
 621
 622         urb = dlfb_get_urb(dlfb);
 623         if (!urb)
 624                 return 0;
 625         cmd = urb->transfer_buffer;
 626
 627         for (i = y; i < y + height ; i++) {
 628                 const int line_offset = dlfb->info->fix.line_length * i;
 629                 const int byte_offset = line_offset + (x * BPP);
 630
 631                 if (dlfb_render_hline(dlfb, &urb,
 632                                       (char *) dlfb->info->fix.smem_start,
 633                                       &cmd, byte_offset, width * BPP,
 634                                       &bytes_identical, &bytes_sent))
 635                         goto error;
 636         }
 637
 638         if (cmd > (char *) urb->transfer_buffer) {
 639                 int len;
 640                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 641                         *cmd++ = 0xAF;
 642                 /* Send partial buffer remaining before exiting */
 643                 len = cmd - (char *) urb->transfer_buffer;
 644                 ret = dlfb_submit_urb(dlfb, urb, len);
 645                 bytes_sent += len;
 646         } else
 647                 dlfb_urb_completion(urb);
 648
 649 error:
 650         atomic_add(bytes_sent, &dlfb->bytes_sent);
 651         atomic_add(bytes_identical, &dlfb->bytes_identical);
 652         atomic_add(width*height*2, &dlfb->bytes_rendered);
 653         end_cycles = get_cycles();
 654         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 655                     >> 10)), /* Kcycles */
 656                    &dlfb->cpu_kcycles_used);
 657
 658         return 0;
 659 }
 660
 661 /*
 662  * Path triggered by usermode clients who write to filesystem
 663  * e.g. cat filename > /dev/fb1
 664  * Not used by X Windows or text-mode console. But useful for testing.
 665  * Slow because of extra copy and we must assume all pixels dirty.
 666  */
 667 static ssize_t dlfb_ops_write(struct fb_info *info, const char __user *buf,
 668                           size_t count, loff_t *ppos)
 669 {
 670         ssize_t result;
 671         struct dlfb_data *dlfb = info->par;
 672         u32 offset = (u32) *ppos;
 673
 674         result = fb_sys_write(info, buf, count, ppos);
 675
 676         if (result > 0) {
 677                 int start = max((int)(offset / info->fix.line_length), 0);
 678                 int lines = min((u32)((result / info->fix.line_length) + 1),
 679                                 (u32)info->var.yres);
 680
 681                 dlfb_handle_damage(dlfb, 0, start, info->var.xres,
 682                         lines, info->screen_base);
 683         }
 684
 685         return result;
 686 }
 687
 688 /* hardware has native COPY command (see libdlo), but not worth it for fbcon */
 689 static void dlfb_ops_copyarea(struct fb_info *info,
 690                                 const struct fb_copyarea *area)
 691 {
 692
 693         struct dlfb_data *dlfb = info->par;
 694
 695         sys_copyarea(info, area);
 696
 697         dlfb_handle_damage(dlfb, area->dx, area->dy,
 698                         area->width, area->height, info->screen_base);
 699 }
 700
 701 static void dlfb_ops_imageblit(struct fb_info *info,
 702                                 const struct fb_image *image)
 703 {
 704         struct dlfb_data *dlfb = info->par;
 705
 706         sys_imageblit(info, image);
 707
 708         dlfb_handle_damage(dlfb, image->dx, image->dy,
 709                         image->width, image->height, info->screen_base);
 710 }
 711
 712 static void dlfb_ops_fillrect(struct fb_info *info,
 713                           const struct fb_fillrect *rect)
 714 {
 715         struct dlfb_data *dlfb = info->par;
 716
 717         sys_fillrect(info, rect);
 718
 719         dlfb_handle_damage(dlfb, rect->dx, rect->dy, rect->width,
 720                               rect->height, info->screen_base);
 721 }
 722
 723 /*
 724  * NOTE: fb_defio.c is holding info->fbdefio.mutex
 725  *   Touching ANY framebuffer memory that triggers a page fault
 726  *   in fb_defio will cause a deadlock, when it also tries to
 727  *   grab the same mutex.
 728  */
 729 static void dlfb_dpy_deferred_io(struct fb_info *info,
 730                                 struct list_head *pagelist)
 731 {
 732         struct page *cur;
 733         struct fb_deferred_io *fbdefio = info->fbdefio;
 734         struct dlfb_data *dlfb = info->par;
 735         struct urb *urb;
 736         char *cmd;
 737         cycles_t start_cycles, end_cycles;
 738         int bytes_sent = 0;
 739         int bytes_identical = 0;
 740         int bytes_rendered = 0;
 741
 742         if (!fb_defio)
 743                 return;
 744
 745         if (!atomic_read(&dlfb->usb_active))
 746                 return;
 747
 748         start_cycles = get_cycles();
 749
 750         urb = dlfb_get_urb(dlfb);
 751         if (!urb)
 752                 return;
 753
 754         cmd = urb->transfer_buffer;
 755
 756         /* walk the written page list and render each to device */
 757         list_for_each_entry(cur, &fbdefio->pagelist, lru) {
 758
 759                 if (dlfb_render_hline(dlfb, &urb, (char *) info->fix.smem_start,
 760                                   &cmd, cur->index << PAGE_SHIFT,
 761                                   PAGE_SIZE, &bytes_identical, &bytes_sent))
 762                         goto error;
 763                 bytes_rendered += PAGE_SIZE;
 764         }
 765
 766         if (cmd > (char *) urb->transfer_buffer) {
 767                 int len;
 768                 if (cmd < (char *) urb->transfer_buffer + urb->transfer_buffer_length)
 769                         *cmd++ = 0xAF;
 770                 /* Send partial buffer remaining before exiting */
 771                 len = cmd - (char *) urb->transfer_buffer;
 772                 dlfb_submit_urb(dlfb, urb, len);
 773                 bytes_sent += len;
 774         } else
 775                 dlfb_urb_completion(urb);
 776
 777 error:
 778         atomic_add(bytes_sent, &dlfb->bytes_sent);
 779         atomic_add(bytes_identical, &dlfb->bytes_identical);
 780         atomic_add(bytes_rendered, &dlfb->bytes_rendered);
 781         end_cycles = get_cycles();
 782         atomic_add(((unsigned int) ((end_cycles - start_cycles)
 783                     >> 10)), /* Kcycles */
 784                    &dlfb->cpu_kcycles_used);
 785 }
 786
 787 static int dlfb_get_edid(struct dlfb_data *dlfb, char *edid, int len)
 788 {
 789         int i, ret;
 790         char *rbuf;
 791
 792         rbuf = kmalloc(2, GFP_KERNEL);
 793         if (!rbuf)
 794                 return 0;
 795
 796         for (i = 0; i < len; i++) {
 797                 ret = usb_control_msg(dlfb->udev,
 798                                       usb_rcvctrlpipe(dlfb->udev, 0), 0x02,
 799                                       (0x80 | (0x02 << 5)), i << 8, 0xA1,
 800                                       rbuf, 2, USB_CTRL_GET_TIMEOUT);
 801                 if (ret < 2) {
 802                         dev_err(&dlfb->udev->dev,
 803                                 "Read EDID byte %d failed: %d\n", i, ret);
 804                         i--;
 805                         break;
 806                 }
 807                 edid[i] = rbuf[1];
 808         }
 809
 810         kfree(rbuf);
 811
 812         return i;
 813 }
 814
 815 static int dlfb_ops_ioctl(struct fb_info *info, unsigned int cmd,
 816                                 unsigned long arg)
 817 {
 818
 819         struct dlfb_data *dlfb = info->par;
 820
 821         if (!atomic_read(&dlfb->usb_active))
 822                 return 0;
 823
 824         /* TODO: Update X server to get this from sysfs instead */
 825         if (cmd == DLFB_IOCTL_RETURN_EDID) {
 826                 void __user *edid = (void __user *)arg;
 827                 if (copy_to_user(edid, dlfb->edid, dlfb->edid_size))
 828                         return -EFAULT;
 829                 return 0;
 830         }
 831
 832         /* TODO: Help propose a standard fb.h ioctl to report mmap damage */
 833         if (cmd == DLFB_IOCTL_REPORT_DAMAGE) {
 834                 struct dloarea area;
 835
 836                 if (copy_from_user(&area, (void __user *)arg,
 837                                   sizeof(struct dloarea)))
 838                         return -EFAULT;
 839
 840                 /*
 841                  * If we have a damage-aware client, turn fb_defio "off"
 842                  * To avoid perf imact of unnecessary page fault handling.
 843                  * Done by resetting the delay for this fb_info to a very
 844                  * long period. Pages will become writable and stay that way.
 845                  * Reset to normal value when all clients have closed this fb.
 846                  */
 847                 if (info->fbdefio)
 848                         info->fbdefio->delay = DL_DEFIO_WRITE_DISABLE;
 849
 850                 if (area.x < 0)
 851                         area.x = 0;
 852
 853                 if (area.x > info->var.xres)
 854                         area.x = info->var.xres;
 855
 856                 if (area.y < 0)
 857                         area.y = 0;
 858
 859                 if (area.y > info->var.yres)
 860                         area.y = info->var.yres;
 861
 862                 dlfb_handle_damage(dlfb, area.x, area.y, area.w, area.h,
 863                            info->screen_base);
 864         }
 865
 866         return 0;
 867 }
 868
 869 /* taken from vesafb */
 870 static int
 871 dlfb_ops_setcolreg(unsigned regno, unsigned red, unsigned green,
 872                unsigned blue, unsigned transp, struct fb_info *info)
 873 {
 874         int err = 0;
 875
 876         if (regno >= info->cmap.len)
 877                 return 1;
 878
 879         if (regno < 16) {
 880                 if (info->var.red.offset == 10) {
 881                         /* 1:5:5:5 */
 882                         ((u32 *) (info->pseudo_palette))[regno] =
 883                             ((red & 0xf800) >> 1) |
 884                             ((green & 0xf800) >> 6) | ((blue & 0xf800) >> 11);
 885                 } else {
 886                         /* 0:5:6:5 */
 887                         ((u32 *) (info->pseudo_palette))[regno] =
 888                             ((red & 0xf800)) |
 889                             ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11);
 890                 }
 891         }
 892
 893         return err;
 894 }
 895
 896 /*
 897  * It's common for several clients to have framebuffer open simultaneously.
 898  * e.g. both fbcon and X. Makes things interesting.
 899  * Assumes caller is holding info->lock (for open and release at least)
 900  */
 901 static int dlfb_ops_open(struct fb_info *info, int user)
 902 {
 903         struct dlfb_data *dlfb = info->par;
 904
 905         /*
 906          * fbcon aggressively connects to first framebuffer it finds,
 907          * preventing other clients (X) from working properly. Usually
 908          * not what the user wants. Fail by default with option to enable.
 909          */
 910         if ((user == 0) && (!console))
 911                 return -EBUSY;
 912
 913         /* If the USB device is gone, we don't accept new opens */
 914         if (dlfb->virtualized)
 915                 return -ENODEV;
 916
 917         dlfb->fb_count++;
 918
 919         if (fb_defio && (info->fbdefio == NULL)) {
 920                 /* enable defio at last moment if not disabled by client */
 921
 922                 struct fb_deferred_io *fbdefio;
 923
 924                 fbdefio = kzalloc(sizeof(struct fb_deferred_io), GFP_KERNEL);
 925
 926                 if (fbdefio) {
 927                         fbdefio->delay = DL_DEFIO_WRITE_DELAY;
 928                         fbdefio->deferred_io = dlfb_dpy_deferred_io;
 929                 }
 930
 931                 info->fbdefio = fbdefio;
 932                 fb_deferred_io_init(info);
 933         }
 934
 935         dev_dbg(info->dev, "open, user=%d fb_info=%p count=%d\n",
 936                 user, info, dlfb->fb_count);
 937
 938         return 0;
 939 }
 940
 941 static void dlfb_ops_destroy(struct fb_info *info)
 942 {
 943         struct dlfb_data *dlfb = info->par;
 944
 945         if (info->cmap.len != 0)
 946                 fb_dealloc_cmap(&info->cmap);
 947         if (info->monspecs.modedb)
 948                 fb_destroy_modedb(info->monspecs.modedb);
 949         vfree(info->screen_base);
 950
 951         fb_destroy_modelist(&info->modelist);
 952
 953         while (!list_empty(&dlfb->deferred_free)) {
 954                 struct dlfb_deferred_free *d = list_entry(dlfb->deferred_free.next, struct dlfb_deferred_free, list);
 955                 list_del(&d->list);
 956                 vfree(d->mem);
 957                 kfree(d);
 958         }
 959         vfree(dlfb->backing_buffer);
 960         kfree(dlfb->edid);
 961         usb_put_dev(dlfb->udev);
 962         kfree(dlfb);
 963
 964         /* Assume info structure is freed after this point */
 965         framebuffer_release(info);
 966 }
 967
 968 /*
 969  * Assumes caller is holding info->lock mutex (for open and release at least)
 970  */
 971 static int dlfb_ops_release(struct fb_info *info, int user)
 972 {
 973         struct dlfb_data *dlfb = info->par;
 974
 975         dlfb->fb_count--;
 976
 977         if ((dlfb->fb_count == 0) && (info->fbdefio)) {
 978                 fb_deferred_io_cleanup(info);
 979                 kfree(info->fbdefio);
 980                 info->fbdefio = NULL;
 981                 info->fbops->fb_mmap = dlfb_ops_mmap;
 982         }
 983
 984         dev_dbg(info->dev, "release, user=%d count=%d\n", user, dlfb->fb_count);
 985
 986         return 0;
 987 }
 988
 989 /*
 990  * Check whether a video mode is supported by the DisplayLink chip
 991  * We start from monitor's modes, so don't need to filter that here
 992  */
 993 static int dlfb_is_valid_mode(struct fb_videomode *mode, struct dlfb_data *dlfb)
 994 {
 995         if (mode->xres * mode->yres > dlfb->sku_pixel_limit)
 996                 return 0;
 997
 998         return 1;
 999 }
1000
1001 static void dlfb_var_color_format(struct fb_var_screeninfo *var)
1002 {
1003         const struct fb_bitfield red = { 11, 5, 0 };
1004         const struct fb_bitfield green = { 5, 6, 0 };
1005         const struct fb_bitfield blue = { 0, 5, 0 };
1006
1007         var->bits_per_pixel = 16;
1008         var->red = red;
1009         var->green = green;
1010         var->blue = blue;
1011 }
1012
1013 static int dlfb_ops_check_var(struct fb_var_screeninfo *var,
1014                                 struct fb_info *info)
1015 {
1016         struct fb_videomode mode;
1017         struct dlfb_data *dlfb = info->par;
1018
1019         /* set device-specific elements of var unrelated to mode */
1020         dlfb_var_color_format(var);
1021
1022         fb_var_to_videomode(&mode, var);
1023
1024         if (!dlfb_is_valid_mode(&mode, dlfb))
1025                 return -EINVAL;
1026
1027         return 0;
1028 }
1029
1030 static int dlfb_ops_set_par(struct fb_info *info)
1031 {
1032         struct dlfb_data *dlfb = info->par;
1033         int result;
1034         u16 *pix_framebuffer;
1035         int i;
1036         struct fb_var_screeninfo fvs;
1037         u32 line_length = info->var.xres * (info->var.bits_per_pixel / 8);
1038
1039         /* clear the activate field because it causes spurious miscompares */
1040         fvs = info->var;
1041         fvs.activate = 0;
1042         fvs.vmode &= ~FB_VMODE_SMOOTH_XPAN;
1043
1044         if (!memcmp(&dlfb->current_mode, &fvs, sizeof(struct fb_var_screeninfo)))
1045                 return 0;
1046
1047         result = dlfb_realloc_framebuffer(dlfb, info, info->var.yres * line_length);
1048         if (result)
1049                 return result;
1050
1051         result = dlfb_set_video_mode(dlfb, &info->var);
1052
1053         if (result)
1054                 return result;
1055
1056         dlfb->current_mode = fvs;
1057         info->fix.line_length = line_length;
1058
1059         if (dlfb->fb_count == 0) {
1060
1061                 /* paint greenscreen */
1062
1063                 pix_framebuffer = (u16 *) info->screen_base;
1064                 for (i = 0; i < info->fix.smem_len / 2; i++)
1065                         pix_framebuffer[i] = 0x37e6;
1066         }
1067
1068         dlfb_handle_damage(dlfb, 0, 0, info->var.xres, info->var.yres,
1069                            info->screen_base);
1070
1071         return 0;
1072 }
1073
1074 /* To fonzi the jukebox (e.g. make blanking changes take effect) */
1075 static char *dlfb_dummy_render(char *buf)
1076 {
1077         *buf++ = 0xAF;
1078         *buf++ = 0x6A; /* copy */
1079         *buf++ = 0x00; /* from address*/
1080         *buf++ = 0x00;
1081         *buf++ = 0x00;
1082         *buf++ = 0x01; /* one pixel */
1083         *buf++ = 0x00; /* to address */
1084         *buf++ = 0x00;
1085         *buf++ = 0x00;
1086         return buf;
1087 }
1088
1089 /*
1090  * In order to come back from full DPMS off, we need to set the mode again
1091  */
1092 static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
1093 {
1094         struct dlfb_data *dlfb = info->par;
1095         char *bufptr;
1096         struct urb *urb;
1097
1098         dev_dbg(info->dev, "blank, mode %d --> %d\n",
1099                 dlfb->blank_mode, blank_mode);
1100
1101         if ((dlfb->blank_mode == FB_BLANK_POWERDOWN) &&
1102             (blank_mode != FB_BLANK_POWERDOWN)) {
1103
1104                 /* returning from powerdown requires a fresh modeset */
1105                 dlfb_set_video_mode(dlfb, &info->var);
1106         }
1107
1108         urb = dlfb_get_urb(dlfb);
1109         if (!urb)
1110                 return 0;
1111
1112         bufptr = (char *) urb->transfer_buffer;
1113         bufptr = dlfb_vidreg_lock(bufptr);
1114         bufptr = dlfb_blanking(bufptr, blank_mode);
1115         bufptr = dlfb_vidreg_unlock(bufptr);
1116
1117         /* seems like a render op is needed to have blank change take effect */
1118         bufptr = dlfb_dummy_render(bufptr);
1119
1120         dlfb_submit_urb(dlfb, urb, bufptr -
1121                         (char *) urb->transfer_buffer);
1122
1123         dlfb->blank_mode = blank_mode;
1124
1125         return 0;
1126 }
1127
1128 static struct fb_ops dlfb_ops = {
1129         .owner = THIS_MODULE,
1130         .fb_read = fb_sys_read,
1131         .fb_write = dlfb_ops_write,
1132         .fb_setcolreg = dlfb_ops_setcolreg,
1133         .fb_fillrect = dlfb_ops_fillrect,
1134         .fb_copyarea = dlfb_ops_copyarea,
1135         .fb_imageblit = dlfb_ops_imageblit,
1136         .fb_mmap = dlfb_ops_mmap,
1137         .fb_ioctl = dlfb_ops_ioctl,
1138         .fb_open = dlfb_ops_open,
1139         .fb_release = dlfb_ops_release,
1140         .fb_blank = dlfb_ops_blank,
1141         .fb_check_var = dlfb_ops_check_var,
1142         .fb_set_par = dlfb_ops_set_par,
1143         .fb_destroy = dlfb_ops_destroy,
1144 };
1145
1146
1147 static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
1148 {
1149         struct dlfb_deferred_free *d = kmalloc(sizeof(struct dlfb_deferred_free), GFP_KERNEL);
1150         if (!d)
1151                 return;
1152         d->mem = mem;
1153         list_add(&d->list, &dlfb->deferred_free);
1154 }
1155
1156 /*
1157  * Assumes &info->lock held by caller
1158  * Assumes no active clients have framebuffer open
1159  */
1160 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
1161 {
1162         u32 old_len = info->fix.smem_len;
1163         const void *old_fb = (const void __force *)info->screen_base;
1164         unsigned char *new_fb;
1165         unsigned char *new_back = NULL;
1166
1167         new_len = PAGE_ALIGN(new_len);
1168
1169         if (new_len > old_len) {
1170                 /*
1171                  * Alloc system memory for virtual framebuffer
1172                  */
1173                 new_fb = vmalloc(new_len);
1174                 if (!new_fb) {
1175                         dev_err(info->dev, "Virtual framebuffer alloc failed\n");
1176                         return -ENOMEM;
1177                 }
1178                 memset(new_fb, 0xff, new_len);
1179
1180                 if (info->screen_base) {
1181                         memcpy(new_fb, old_fb, old_len);
1182                         dlfb_deferred_vfree(dlfb, (void __force *)info->screen_base);
1183                 }
1184
1185                 info->screen_base = (char __iomem *)new_fb;
1186                 info->fix.smem_len = new_len;
1187                 info->fix.smem_start = (unsigned long) new_fb;
1188                 info->flags = udlfb_info_flags;
1189
1190                 /*
1191                  * Second framebuffer copy to mirror the framebuffer state
1192                  * on the physical USB device. We can function without this.
1193                  * But with imperfect damage info we may send pixels over USB
1194                  * that were, in fact, unchanged - wasting limited USB bandwidth
1195                  */
1196                 if (shadow)
1197                         new_back = vzalloc(new_len);
1198                 if (!new_back)
1199                         dev_info(info->dev,
1200                                  "No shadow/backing buffer allocated\n");
1201                 else {
1202                         dlfb_deferred_vfree(dlfb, dlfb->backing_buffer);
1203                         dlfb->backing_buffer = new_back;
1204                 }
1205         }
1206         return 0;
1207 }
1208
1209 /*
1210  * 1) Get EDID from hw, or use sw default
1211  * 2) Parse into various fb_info structs
1212  * 3) Allocate virtual framebuffer memory to back highest res mode
1213  *
1214  * Parses EDID into three places used by various parts of fbdev:
1215  * fb_var_screeninfo contains the timing of the monitor's preferred mode
1216  * fb_info.monspecs is full parsed EDID info, including monspecs.modedb
1217  * fb_info.modelist is a linked list of all monitor & VESA modes which work
1218  *
1219  * If EDID is not readable/valid, then modelist is all VESA modes,
1220  * monspecs is NULL, and fb_var_screeninfo is set to safe VESA mode
1221  * Returns 0 if successful
1222  */
1223 static int dlfb_setup_modes(struct dlfb_data *dlfb,
1224                            struct fb_info *info,
1225                            char *default_edid, size_t default_edid_size)
1226 {
1227         char *edid;
1228         int i, result = 0, tries = 3;
1229         struct device *dev = info->device;
1230         struct fb_videomode *mode;
1231         const struct fb_videomode *default_vmode = NULL;
1232
1233         if (info->dev) {
1234                 /* only use mutex if info has been registered */
1235                 mutex_lock(&info->lock);
1236                 /* parent device is used otherwise */
1237                 dev = info->dev;
1238         }
1239
1240         edid = kmalloc(EDID_LENGTH, GFP_KERNEL);
1241         if (!edid) {
1242                 result = -ENOMEM;
1243                 goto error;
1244         }
1245
1246         fb_destroy_modelist(&info->modelist);
1247         memset(&info->monspecs, 0, sizeof(info->monspecs));
1248
1249         /*
1250          * Try to (re)read EDID from hardware first
1251          * EDID data may return, but not parse as valid
1252          * Try again a few times, in case of e.g. analog cable noise
1253          */
1254         while (tries--) {
1255
1256                 i = dlfb_get_edid(dlfb, edid, EDID_LENGTH);
1257
1258                 if (i >= EDID_LENGTH)
1259                         fb_edid_to_monspecs(edid, &info->monspecs);
1260
1261                 if (info->monspecs.modedb_len > 0) {
1262                         dlfb->edid = edid;
1263                         dlfb->edid_size = i;
1264                         break;
1265                 }
1266         }
1267
1268         /* If that fails, use a previously returned EDID if available */
1269         if (info->monspecs.modedb_len == 0) {
1270                 dev_err(dev, "Unable to get valid EDID from device/display\n");
1271
1272                 if (dlfb->edid) {
1273                         fb_edid_to_monspecs(dlfb->edid, &info->monspecs);
1274                         if (info->monspecs.modedb_len > 0)
1275                                 dev_err(dev, "Using previously queried EDID\n");
1276                 }
1277         }
1278
1279         /* If that fails, use the default EDID we were handed */
1280         if (info->monspecs.modedb_len == 0) {
1281                 if (default_edid_size >= EDID_LENGTH) {
1282                         fb_edid_to_monspecs(default_edid, &info->monspecs);
1283                         if (info->monspecs.modedb_len > 0) {
1284                                 memcpy(edid, default_edid, default_edid_size);
1285                                 dlfb->edid = edid;
1286                                 dlfb->edid_size = default_edid_size;
1287                                 dev_err(dev, "Using default/backup EDID\n");
1288                         }
1289                 }
1290         }
1291
1292         /* If we've got modes, let's pick a best default mode */
1293         if (info->monspecs.modedb_len > 0) {
1294
1295                 for (i = 0; i < info->monspecs.modedb_len; i++) {
1296                         mode = &info->monspecs.modedb[i];
1297                         if (dlfb_is_valid_mode(mode, dlfb)) {
1298                                 fb_add_videomode(mode, &info->modelist);
1299                         } else {
1300                                 dev_dbg(dev, "Specified mode %dx%d too big\n",
1301                                         mode->xres, mode->yres);
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                         mode = (struct fb_videomode *)&vesa_modes[i];
1326                         if (dlfb_is_valid_mode(mode, dlfb))
1327                                 fb_add_videomode(mode, &info->modelist);
1328                         else
1329                                 dev_dbg(dev, "VESA mode %dx%d too big\n",
1330                                         mode->xres, mode->yres);
1331                 }
1332
1333                 /*
1334                  * default to resolution safe for projectors
1335                  * (since they are most common case without EDID)
1336                  */
1337                 fb_vmode.xres = 800;
1338                 fb_vmode.yres = 600;
1339                 fb_vmode.refresh = 60;
1340                 default_vmode = fb_find_nearest_mode(&fb_vmode,
1341                                                      &info->modelist);
1342         }
1343
1344         /* If we have good mode and no active clients*/
1345         if ((default_vmode != NULL) && (dlfb->fb_count == 0)) {
1346
1347                 fb_videomode_to_var(&info->var, default_vmode);
1348                 dlfb_var_color_format(&info->var);
1349
1350                 /*
1351                  * with mode size info, we can now alloc our framebuffer.
1352                  */
1353                 memcpy(&info->fix, &dlfb_fix, sizeof(dlfb_fix));
1354         } else
1355                 result = -EINVAL;
1356
1357 error:
1358         if (edid && (dlfb->edid != edid))
1359                 kfree(edid);
1360
1361         if (info->dev)
1362                 mutex_unlock(&info->lock);
1363
1364         return result;
1365 }
1366
1367 static ssize_t metrics_bytes_rendered_show(struct device *fbdev,
1368                                    struct device_attribute *a, char *buf) {
1369         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1370         struct dlfb_data *dlfb = fb_info->par;
1371         return snprintf(buf, PAGE_SIZE, "%u\n",
1372                         atomic_read(&dlfb->bytes_rendered));
1373 }
1374
1375 static ssize_t metrics_bytes_identical_show(struct device *fbdev,
1376                                    struct device_attribute *a, char *buf) {
1377         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1378         struct dlfb_data *dlfb = fb_info->par;
1379         return snprintf(buf, PAGE_SIZE, "%u\n",
1380                         atomic_read(&dlfb->bytes_identical));
1381 }
1382
1383 static ssize_t metrics_bytes_sent_show(struct device *fbdev,
1384                                    struct device_attribute *a, char *buf) {
1385         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1386         struct dlfb_data *dlfb = fb_info->par;
1387         return snprintf(buf, PAGE_SIZE, "%u\n",
1388                         atomic_read(&dlfb->bytes_sent));
1389 }
1390
1391 static ssize_t metrics_cpu_kcycles_used_show(struct device *fbdev,
1392                                    struct device_attribute *a, char *buf) {
1393         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1394         struct dlfb_data *dlfb = fb_info->par;
1395         return snprintf(buf, PAGE_SIZE, "%u\n",
1396                         atomic_read(&dlfb->cpu_kcycles_used));
1397 }
1398
1399 static ssize_t edid_show(
1400                         struct file *filp,
1401                         struct kobject *kobj, struct bin_attribute *a,
1402                          char *buf, loff_t off, size_t count) {
1403         struct device *fbdev = container_of(kobj, struct device, kobj);
1404         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1405         struct dlfb_data *dlfb = fb_info->par;
1406
1407         if (dlfb->edid == NULL)
1408                 return 0;
1409
1410         if ((off >= dlfb->edid_size) || (count > dlfb->edid_size))
1411                 return 0;
1412
1413         if (off + count > dlfb->edid_size)
1414                 count = dlfb->edid_size - off;
1415
1416         memcpy(buf, dlfb->edid, count);
1417
1418         return count;
1419 }
1420
1421 static ssize_t edid_store(
1422                         struct file *filp,
1423                         struct kobject *kobj, struct bin_attribute *a,
1424                         char *src, loff_t src_off, size_t src_size) {
1425         struct device *fbdev = container_of(kobj, struct device, kobj);
1426         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1427         struct dlfb_data *dlfb = fb_info->par;
1428         int ret;
1429
1430         /* We only support write of entire EDID at once, no offset*/
1431         if ((src_size != EDID_LENGTH) || (src_off != 0))
1432                 return -EINVAL;
1433
1434         ret = dlfb_setup_modes(dlfb, fb_info, src, src_size);
1435         if (ret)
1436                 return ret;
1437
1438         if (!dlfb->edid || memcmp(src, dlfb->edid, src_size))
1439                 return -EINVAL;
1440
1441         ret = dlfb_ops_set_par(fb_info);
1442         if (ret)
1443                 return ret;
1444
1445         return src_size;
1446 }
1447
1448 static ssize_t metrics_reset_store(struct device *fbdev,
1449                            struct device_attribute *attr,
1450                            const char *buf, size_t count)
1451 {
1452         struct fb_info *fb_info = dev_get_drvdata(fbdev);
1453         struct dlfb_data *dlfb = fb_info->par;
1454
1455         atomic_set(&dlfb->bytes_rendered, 0);
1456         atomic_set(&dlfb->bytes_identical, 0);
1457         atomic_set(&dlfb->bytes_sent, 0);
1458         atomic_set(&dlfb->cpu_kcycles_used, 0);
1459
1460         return count;
1461 }
1462
1463 static const struct bin_attribute edid_attr = {
1464         .attr.name = "edid",
1465         .attr.mode = 0666,
1466         .size = EDID_LENGTH,
1467         .read = edid_show,
1468         .write = edid_store
1469 };
1470
1471 static const struct device_attribute fb_device_attrs[] = {
1472         __ATTR_RO(metrics_bytes_rendered),
1473         __ATTR_RO(metrics_bytes_identical),
1474         __ATTR_RO(metrics_bytes_sent),
1475         __ATTR_RO(metrics_cpu_kcycles_used),
1476         __ATTR(metrics_reset, S_IWUSR, NULL, metrics_reset_store),
1477 };
1478
1479 /*
1480  * This is necessary before we can communicate with the display controller.
1481  */
1482 static int dlfb_select_std_channel(struct dlfb_data *dlfb)
1483 {
1484         int ret;
1485         void *buf;
1486         static const u8 set_def_chn[] = {
1487                                 0x57, 0xCD, 0xDC, 0xA7,
1488                                 0x1C, 0x88, 0x5E, 0x15,
1489                                 0x60, 0xFE, 0xC6, 0x97,
1490                                 0x16, 0x3D, 0x47, 0xF2  };
1491
1492         buf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
1493
1494         if (!buf)
1495                 return -ENOMEM;
1496
1497         ret = usb_control_msg(dlfb->udev, usb_sndctrlpipe(dlfb->udev, 0),
1498                         NR_USB_REQUEST_CHANNEL,
1499                         (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
1500                         buf, sizeof(set_def_chn), USB_CTRL_SET_TIMEOUT);
1501
1502         kfree(buf);
1503
1504         return ret;
1505 }
1506
1507 static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb,
1508                                         struct usb_interface *intf)
1509 {
1510         char *desc;
1511         char *buf;
1512         char *desc_end;
1513         int total_len;
1514
1515         buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
1516         if (!buf)
1517                 return false;
1518         desc = buf;
1519
1520         total_len = usb_get_descriptor(interface_to_usbdev(intf),
1521                                         0x5f, /* vendor specific */
1522                                         0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
1523
1524         /* if not found, look in configuration descriptor */
1525         if (total_len < 0) {
1526                 if (0 == usb_get_extra_descriptor(intf->cur_altsetting,
1527                         0x5f, &desc))
1528                         total_len = (int) desc[0];
1529         }
1530
1531         if (total_len > 5) {
1532                 dev_info(&intf->dev,
1533                          "vendor descriptor length: %d data: %11ph\n",
1534                          total_len, desc);
1535
1536                 if ((desc[0] != total_len) || /* descriptor length */
1537                     (desc[1] != 0x5f) ||   /* vendor descriptor type */
1538                     (desc[2] != 0x01) ||   /* version (2 bytes) */
1539                     (desc[3] != 0x00) ||
1540                     (desc[4] != total_len - 2)) /* length after type */
1541                         goto unrecognized;
1542
1543                 desc_end = desc + total_len;
1544                 desc += 5; /* the fixed header we've already parsed */
1545
1546                 while (desc < desc_end) {
1547                         u8 length;
1548                         u16 key;
1549
1550                         key = *desc++;
1551                         key |= (u16)*desc++ << 8;
1552                         length = *desc++;
1553
1554                         switch (key) {
1555                         case 0x0200: { /* max_area */
1556                                 u32 max_area = *desc++;
1557                                 max_area |= (u32)*desc++ << 8;
1558                                 max_area |= (u32)*desc++ << 16;
1559                                 max_area |= (u32)*desc++ << 24;
1560                                 dev_warn(&intf->dev,
1561                                          "DL chip limited to %d pixel modes\n",
1562                                          max_area);
1563                                 dlfb->sku_pixel_limit = max_area;
1564                                 break;
1565                         }
1566                         default:
1567                                 break;
1568                         }
1569                         desc += length;
1570                 }
1571         } else {
1572                 dev_info(&intf->dev, "vendor descriptor not available (%d)\n",
1573                          total_len);
1574         }
1575
1576         goto success;
1577
1578 unrecognized:
1579         /* allow udlfb to load for now even if firmware unrecognized */
1580         dev_err(&intf->dev, "Unrecognized vendor firmware descriptor\n");
1581
1582 success:
1583         kfree(buf);
1584         return true;
1585 }
1586
1587 static int dlfb_usb_probe(struct usb_interface *intf,
1588                           const struct usb_device_id *id)
1589 {
1590         int i;
1591         const struct device_attribute *attr;
1592         struct dlfb_data *dlfb;
1593         struct fb_info *info;
1594         int retval = -ENOMEM;
1595         struct usb_device *usbdev = interface_to_usbdev(intf);
1596
1597         /* usb initialization */
1598         dlfb = kzalloc(sizeof(*dlfb), GFP_KERNEL);
1599         if (!dlfb) {
1600                 dev_err(&intf->dev, "%s: failed to allocate dlfb\n", __func__);
1601                 return -ENOMEM;
1602         }
1603
1604         INIT_LIST_HEAD(&dlfb->deferred_free);
1605
1606         dlfb->udev = usb_get_dev(usbdev);
1607         usb_set_intfdata(intf, dlfb);
1608
1609         dev_dbg(&intf->dev, "console enable=%d\n", console);
1610         dev_dbg(&intf->dev, "fb_defio enable=%d\n", fb_defio);
1611         dev_dbg(&intf->dev, "shadow enable=%d\n", shadow);
1612
1613         dlfb->sku_pixel_limit = 2048 * 1152; /* default to maximum */
1614
1615         if (!dlfb_parse_vendor_descriptor(dlfb, intf)) {
1616                 dev_err(&intf->dev,
1617                         "firmware not recognized, incompatible device?\n");
1618                 goto error;
1619         }
1620
1621         if (pixel_limit) {
1622                 dev_warn(&intf->dev,
1623                          "DL chip limit of %d overridden to %d\n",
1624                          dlfb->sku_pixel_limit, pixel_limit);
1625                 dlfb->sku_pixel_limit = pixel_limit;
1626         }
1627
1628
1629         /* allocates framebuffer driver structure, not framebuffer memory */
1630         info = framebuffer_alloc(0, &dlfb->udev->dev);
1631         if (!info) {
1632                 dev_err(&dlfb->udev->dev, "framebuffer_alloc failed\n");
1633                 goto error;
1634         }
1635
1636         dlfb->info = info;
1637         info->par = dlfb;
1638         info->pseudo_palette = dlfb->pseudo_palette;
1639         dlfb->ops = dlfb_ops;
1640         info->fbops = &dlfb->ops;
1641
1642         INIT_LIST_HEAD(&info->modelist);
1643
1644         if (!dlfb_alloc_urb_list(dlfb, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
1645                 retval = -ENOMEM;
1646                 dev_err(&intf->dev, "unable to allocate urb list\n");
1647                 goto error;
1648         }
1649
1650         /* We don't register a new USB class. Our client interface is dlfbev */
1651
1652         retval = fb_alloc_cmap(&info->cmap, 256, 0);
1653         if (retval < 0) {
1654                 dev_err(info->device, "cmap allocation failed: %d\n", retval);
1655                 goto error;
1656         }
1657
1658         retval = dlfb_setup_modes(dlfb, info, NULL, 0);
1659         if (retval != 0) {
1660                 dev_err(info->device,
1661                         "unable to find common mode for display and adapter\n");
1662                 goto error;
1663         }
1664
1665         /* ready to begin using device */
1666
1667         atomic_set(&dlfb->usb_active, 1);
1668         dlfb_select_std_channel(dlfb);
1669
1670         dlfb_ops_check_var(&info->var, info);
1671         retval = dlfb_ops_set_par(info);
1672         if (retval)
1673                 goto error;
1674
1675         retval = register_framebuffer(info);
1676         if (retval < 0) {
1677                 dev_err(info->device, "unable to register framebuffer: %d\n",
1678                         retval);
1679                 goto error;
1680         }
1681
1682         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++) {
1683                 attr = &fb_device_attrs[i];
1684                 retval = device_create_file(info->dev, attr);
1685                 if (retval)
1686                         dev_warn(info->device,
1687                                  "failed to create '%s' attribute: %d\n",
1688                                  attr->attr.name, retval);
1689         }
1690
1691         retval = device_create_bin_file(info->dev, &edid_attr);
1692         if (retval)
1693                 dev_warn(info->device, "failed to create '%s' attribute: %d\n",
1694                          edid_attr.attr.name, retval);
1695
1696         dev_info(info->device,
1697                  "%s is DisplayLink USB device (%dx%d, %dK framebuffer memory)\n",
1698                  dev_name(info->dev), info->var.xres, info->var.yres,
1699                  ((dlfb->backing_buffer) ?
1700                  info->fix.smem_len * 2 : info->fix.smem_len) >> 10);
1701         return 0;
1702
1703 error:
1704         if (dlfb->info) {
1705                 dlfb_ops_destroy(dlfb->info);
1706         } else {
1707                 usb_put_dev(dlfb->udev);
1708                 kfree(dlfb);
1709         }
1710         return retval;
1711 }
1712
1713 static void dlfb_usb_disconnect(struct usb_interface *intf)
1714 {
1715         struct dlfb_data *dlfb;
1716         struct fb_info *info;
1717         int i;
1718
1719         dlfb = usb_get_intfdata(intf);
1720         info = dlfb->info;
1721
1722         dev_dbg(&intf->dev, "USB disconnect starting\n");
1723
1724         /* we virtualize until all fb clients release. Then we free */
1725         dlfb->virtualized = true;
1726
1727         /* When non-active we'll update virtual framebuffer, but no new urbs */
1728         atomic_set(&dlfb->usb_active, 0);
1729
1730         /* this function will wait for all in-flight urbs to complete */
1731         dlfb_free_urb_list(dlfb);
1732
1733         /* remove udlfb's sysfs interfaces */
1734         for (i = 0; i < ARRAY_SIZE(fb_device_attrs); i++)
1735                 device_remove_file(info->dev, &fb_device_attrs[i]);
1736         device_remove_bin_file(info->dev, &edid_attr);
1737
1738         unregister_framebuffer(info);
1739 }
1740
1741 static struct usb_driver dlfb_driver = {
1742         .name = "udlfb",
1743         .probe = dlfb_usb_probe,
1744         .disconnect = dlfb_usb_disconnect,
1745         .id_table = id_table,
1746 };
1747
1748 module_usb_driver(dlfb_driver);
1749
1750 static void dlfb_urb_completion(struct urb *urb)
1751 {
1752         struct urb_node *unode = urb->context;
1753         struct dlfb_data *dlfb = unode->dlfb;
1754         unsigned long flags;
1755
1756         switch (urb->status) {
1757         case 0:
1758                 /* success */
1759                 break;
1760         case -ECONNRESET:
1761         case -ENOENT:
1762         case -ESHUTDOWN:
1763                 /* sync/async unlink faults aren't errors */
1764                 break;
1765         default:
1766                 dev_err(&dlfb->udev->dev,
1767                         "%s - nonzero write bulk status received: %d\n",
1768                         __func__, urb->status);
1769                 atomic_set(&dlfb->lost_pixels, 1);
1770                 break;
1771         }
1772
1773         urb->transfer_buffer_length = dlfb->urbs.size; /* reset to actual */
1774
1775         spin_lock_irqsave(&dlfb->urbs.lock, flags);
1776         list_add_tail(&unode->entry, &dlfb->urbs.list);
1777         dlfb->urbs.available++;
1778         spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
1779
1780         up(&dlfb->urbs.limit_sem);
1781 }
1782
1783 static void dlfb_free_urb_list(struct dlfb_data *dlfb)
1784 {
1785         int count = dlfb->urbs.count;
1786         struct list_head *node;
1787         struct urb_node *unode;
1788         struct urb *urb;
1789
1790         /* keep waiting and freeing, until we've got 'em all */
1791         while (count--) {
1792                 down(&dlfb->urbs.limit_sem);
1793
1794                 spin_lock_irq(&dlfb->urbs.lock);
1795
1796                 node = dlfb->urbs.list.next; /* have reserved one with sem */
1797                 list_del_init(node);
1798
1799                 spin_unlock_irq(&dlfb->urbs.lock);
1800
1801                 unode = list_entry(node, struct urb_node, entry);
1802                 urb = unode->urb;
1803
1804                 /* Free each separately allocated piece */
1805                 usb_free_coherent(urb->dev, dlfb->urbs.size,
1806                                   urb->transfer_buffer, urb->transfer_dma);
1807                 usb_free_urb(urb);
1808                 kfree(node);
1809         }
1810
1811         dlfb->urbs.count = 0;
1812 }
1813
1814 static int dlfb_alloc_urb_list(struct dlfb_data *dlfb, int count, size_t size)
1815 {
1816         struct urb *urb;
1817         struct urb_node *unode;
1818         char *buf;
1819         size_t wanted_size = count * size;
1820
1821         spin_lock_init(&dlfb->urbs.lock);
1822
1823 retry:
1824         dlfb->urbs.size = size;
1825         INIT_LIST_HEAD(&dlfb->urbs.list);
1826
1827         sema_init(&dlfb->urbs.limit_sem, 0);
1828         dlfb->urbs.count = 0;
1829         dlfb->urbs.available = 0;
1830
1831         while (dlfb->urbs.count * size < wanted_size) {
1832                 unode = kzalloc(sizeof(*unode), GFP_KERNEL);
1833                 if (!unode)
1834                         break;
1835                 unode->dlfb = dlfb;
1836
1837                 urb = usb_alloc_urb(0, GFP_KERNEL);
1838                 if (!urb) {
1839                         kfree(unode);
1840                         break;
1841                 }
1842                 unode->urb = urb;
1843
1844                 buf = usb_alloc_coherent(dlfb->udev, size, GFP_KERNEL,
1845                                          &urb->transfer_dma);
1846                 if (!buf) {
1847                         kfree(unode);
1848                         usb_free_urb(urb);
1849                         if (size > PAGE_SIZE) {
1850                                 size /= 2;
1851                                 dlfb_free_urb_list(dlfb);
1852                                 goto retry;
1853                         }
1854                         break;
1855                 }
1856
1857                 /* urb->transfer_buffer_length set to actual before submit */
1858                 usb_fill_bulk_urb(urb, dlfb->udev, usb_sndbulkpipe(dlfb->udev, 1),
1859                         buf, size, dlfb_urb_completion, unode);
1860                 urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
1861
1862                 list_add_tail(&unode->entry, &dlfb->urbs.list);
1863
1864                 up(&dlfb->urbs.limit_sem);
1865                 dlfb->urbs.count++;
1866                 dlfb->urbs.available++;
1867         }
1868
1869         return dlfb->urbs.count;
1870 }
1871
1872 static struct urb *dlfb_get_urb(struct dlfb_data *dlfb)
1873 {
1874         int ret;
1875         struct list_head *entry;
1876         struct urb_node *unode;
1877
1878         /* Wait for an in-flight buffer to complete and get re-queued */
1879         ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
1880         if (ret) {
1881                 atomic_set(&dlfb->lost_pixels, 1);
1882                 dev_warn(&dlfb->udev->dev,
1883                          "wait for urb interrupted: %d available: %d\n",
1884                          ret, dlfb->urbs.available);
1885                 return NULL;
1886         }
1887
1888         spin_lock_irq(&dlfb->urbs.lock);
1889
1890         BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
1891         entry = dlfb->urbs.list.next;
1892         list_del_init(entry);
1893         dlfb->urbs.available--;
1894
1895         spin_unlock_irq(&dlfb->urbs.lock);
1896
1897         unode = list_entry(entry, struct urb_node, entry);
1898         return unode->urb;
1899 }
1900
1901 static int dlfb_submit_urb(struct dlfb_data *dlfb, struct urb *urb, size_t len)
1902 {
1903         int ret;
1904
1905         BUG_ON(len > dlfb->urbs.size);
1906
1907         urb->transfer_buffer_length = len; /* set to actual payload len */
1908         ret = usb_submit_urb(urb, GFP_KERNEL);
1909         if (ret) {
1910                 dlfb_urb_completion(urb); /* because no one else will */
1911                 atomic_set(&dlfb->lost_pixels, 1);
1912                 dev_err(&dlfb->udev->dev, "submit urb error: %d\n", ret);
1913         }
1914         return ret;
1915 }
1916
1917 module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1918 MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1919
1920 module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1921 MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1922
1923 module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1924 MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1925
1926 module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1927 MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
1928
1929 MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
1930               "Jaya Kumar <jayakumar.lkml@gmail.com>, "
1931               "Bernie Thompson <bernie@plugable.com>");
1932 MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
1933 MODULE_LICENSE("GPL");
1934