linux/drivers/video/udlfb.c
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   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
  35static 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
  45static 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 */
  57static 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};
  69MODULE_DEVICE_TABLE(usb, id_table);
  70
  71/* module options */
  72static bool console = 1; /* Allow fbcon to open framebuffer */
  73static bool fb_defio = 1;  /* Detect mmap writes using page faults */
  74static bool shadow = 1; /* Optionally disable shadow framebuffer */
  75static int pixel_limit; /* Optionally force a pixel resolution limit */
  76
  77/* dlfb keeps a list of urbs for efficient bulk transfers */
  78static void dlfb_urb_completion(struct urb *urb);
  79static struct urb *dlfb_get_urb(struct dlfb_data *dev);
  80static int dlfb_submit_urb(struct dlfb_data *dev, struct urb * urb, size_t len);
  81static int dlfb_alloc_urb_list(struct dlfb_data *dev, int count, size_t size);
  82static 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 */
  88static 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
  97static char *dlfb_vidreg_lock(char *buf)
  98{
  99        return dlfb_set_register(buf, 0xFF, 0x00);
 100}
 101
 102static 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 */
 117static 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
 143static char *dlfb_set_color_depth(char *buf, u8 selection)
 144{
 145        return dlfb_set_register(buf, 0x00, selection);
 146}
 147
 148static 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 */
 160static 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
 167static 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 */
 177static 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 */
 192static 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 */
 209static 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 */
 218static 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 */
 277static 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
 320static 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 */
 362static 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 */
 423static 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 = NULL;
 438                uint8_t *cmd_pixels_count_byte = NULL;
 439                const uint16_t *raw_pixel_start = NULL;
 440                const uint16_t *cmd_pixel_start, *cmd_pixel_end = NULL;
 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 */
 518static 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
 576static 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
 625error:
 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 */
 643static 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 */
 665static 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
 677static 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
 688static 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 */
 705static 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
 750error:
 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
 760static 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
 788static 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 */
 843static int
 844dlfb_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 */
 874static 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 */
 921static 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
 935static 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
 943static 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
 973static 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 */
 982static 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 */
1011static 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
1028static 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
1040static 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
1060static 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) */
1087static 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 */
1104static 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
1140static 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 */
1162static 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
1214error:
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 */
1232static 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
1364error:
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
1374static 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
1382static 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
1390static 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
1398static 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
1406static 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
1431static 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
1456static 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
1471static 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
1479static 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 */
1490static 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
1505static 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
1576unrecognized:
1577        /* allow udlfb to load for now even if firmware unrecognized */
1578        pr_err("Unrecognized vendor firmware descriptor\n");
1579
1580success:
1581        kfree(buf);
1582        return true;
1583}
1584
1585static void dlfb_init_framebuffer_work(struct work_struct *work);
1586
1587static 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 = NULL;
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
1651error:
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
1663static 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
1734error:
1735        dlfb_free_framebuffer(dev);
1736}
1737
1738static 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
1782static 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
1789module_usb_driver(dlfb_driver);
1790
1791static 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
1825static 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
1864static 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
1919static 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
1948error:
1949        return urb;
1950}
1951
1952static 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
1968module_param(console, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1969MODULE_PARM_DESC(console, "Allow fbcon to open framebuffer");
1970
1971module_param(fb_defio, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1972MODULE_PARM_DESC(fb_defio, "Page fault detection of mmap writes");
1973
1974module_param(shadow, bool, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1975MODULE_PARM_DESC(shadow, "Shadow vid mem. Disable to save mem but lose perf");
1976
1977module_param(pixel_limit, int, S_IWUSR | S_IRUSR | S_IWGRP | S_IRGRP);
1978MODULE_PARM_DESC(pixel_limit, "Force limit on max mode (in x*y pixels)");
1979
1980MODULE_AUTHOR("Roberto De Ioris <roberto@unbit.it>, "
1981              "Jaya Kumar <jayakumar.lkml@gmail.com>, "
1982              "Bernie Thompson <bernie@plugable.com>");
1983MODULE_DESCRIPTION("DisplayLink kernel framebuffer driver");
1984MODULE_LICENSE("GPL");
1985
1986
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