hw/display/edid-generate.c

   1 /*
   2  * QEMU EDID generator.
   3  *
   4  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   5  * See the COPYING file in the top-level directory.
   6  */
   7 #include "qemu/osdep.h"
   8 #include "qemu/bswap.h"
   9 #include "hw/display/edid.h"
  10
  11 static const struct edid_mode {
  12     uint32_t xres;
  13     uint32_t yres;
  14     uint32_t byte;
  15     uint32_t xtra3;
  16     uint32_t bit;
  17     uint32_t dta;
  18 } modes[] = {
  19     /* dea/dta extension timings (all @ 50 Hz) */
  20     { .xres = 5120,   .yres = 2160,   .dta = 125 },
  21     { .xres = 4096,   .yres = 2160,   .dta = 101 },
  22     { .xres = 3840,   .yres = 2160,   .dta =  96 },
  23     { .xres = 2560,   .yres = 1080,   .dta =  89 },
  24     { .xres = 2048,   .yres = 1152 },
  25     { .xres = 1920,   .yres = 1080,   .dta =  31 },
  26
  27     /* additional standard timings 3 (all @ 60Hz) */
  28     { .xres = 1920,   .yres = 1200,   .xtra3 = 10,   .bit = 0 },
  29     { .xres = 1600,   .yres = 1200,   .xtra3 =  9,   .bit = 2 },
  30     { .xres = 1680,   .yres = 1050,   .xtra3 =  9,   .bit = 5 },
  31     { .xres = 1440,   .yres =  900,   .xtra3 =  8,   .bit = 5 },
  32     { .xres = 1280,   .yres = 1024,   .xtra3 =  7,   .bit = 1 },
  33     { .xres = 1280,   .yres =  960,   .xtra3 =  7,   .bit = 3 },
  34     { .xres = 1280,   .yres =  768,   .xtra3 =  7,   .bit = 6 },
  35
  36     { .xres = 1920,   .yres = 1440,   .xtra3 = 11,   .bit = 5 },
  37     { .xres = 1856,   .yres = 1392,   .xtra3 = 10,   .bit = 3 },
  38     { .xres = 1792,   .yres = 1344,   .xtra3 = 10,   .bit = 5 },
  39     { .xres = 1440,   .yres = 1050,   .xtra3 =  8,   .bit = 1 },
  40     { .xres = 1360,   .yres =  768,   .xtra3 =  8,   .bit = 7 },
  41
  42     /* established timings (all @ 60Hz) */
  43     { .xres = 1024,   .yres =  768,   .byte  = 36,   .bit = 3 },
  44     { .xres =  800,   .yres =  600,   .byte  = 35,   .bit = 0 },
  45     { .xres =  640,   .yres =  480,   .byte  = 35,   .bit = 5 },
  46 };
  47
  48 typedef struct Timings {
  49     uint32_t xfront;
  50     uint32_t xsync;
  51     uint32_t xblank;
  52
  53     uint32_t yfront;
  54     uint32_t ysync;
  55     uint32_t yblank;
  56
  57     uint64_t clock;
  58 } Timings;
  59
  60 static void generate_timings(Timings *timings, uint32_t refresh_rate,
  61                              uint32_t xres, uint32_t yres)
  62 {
  63     /* pull some realistic looking timings out of thin air */
  64     timings->xfront = xres * 25 / 100;
  65     timings->xsync  = xres *  3 / 100;
  66     timings->xblank = xres * 35 / 100;
  67
  68     timings->yfront = yres *  5 / 1000;
  69     timings->ysync  = yres *  5 / 1000;
  70     timings->yblank = yres * 35 / 1000;
  71
  72     timings->clock  = ((uint64_t)refresh_rate *
  73                        (xres + timings->xblank) *
  74                        (yres + timings->yblank)) / 10000000;
  75 }
  76
  77 static void edid_ext_dta(uint8_t *dta)
  78 {
  79     dta[0] = 0x02;
  80     dta[1] = 0x03;
  81     dta[2] = 0x05;
  82     dta[3] = 0x00;
  83
  84     /* video data block */
  85     dta[4] = 0x40;
  86 }
  87
  88 static void edid_ext_dta_mode(uint8_t *dta, uint8_t nr)
  89 {
  90     dta[dta[2]] = nr;
  91     dta[2]++;
  92     dta[4]++;
  93 }
  94
  95 static int edid_std_mode(uint8_t *mode, uint32_t xres, uint32_t yres)
  96 {
  97     uint32_t aspect;
  98
  99     if (xres == 0 || yres == 0) {
 100         mode[0] = 0x01;
 101         mode[1] = 0x01;
 102         return 0;
 103
 104     } else if (xres * 10 == yres * 16) {
 105         aspect = 0;
 106     } else if (xres * 3 == yres * 4) {
 107         aspect = 1;
 108     } else if (xres * 4 == yres * 5) {
 109         aspect = 2;
 110     } else if (xres * 9 == yres * 16) {
 111         aspect = 3;
 112     } else {
 113         return -1;
 114     }
 115
 116     if ((xres / 8) - 31 > 255) {
 117         return -1;
 118     }
 119
 120     mode[0] = (xres / 8) - 31;
 121     mode[1] = ((aspect << 6) | (60 - 60));
 122     return 0;
 123 }
 124
 125 static void edid_fill_modes(uint8_t *edid, uint8_t *xtra3, uint8_t *dta,
 126                             uint32_t maxx, uint32_t maxy)
 127 {
 128     const struct edid_mode *mode;
 129     int std = 38;
 130     int rc, i;
 131
 132     for (i = 0; i < ARRAY_SIZE(modes); i++) {
 133         mode = modes + i;
 134
 135         if ((maxx && mode->xres > maxx) ||
 136             (maxy && mode->yres > maxy)) {
 137             continue;
 138         }
 139
 140         if (mode->byte) {
 141             edid[mode->byte] |= (1 << mode->bit);
 142         } else if (std < 54) {
 143             rc = edid_std_mode(edid + std, mode->xres, mode->yres);
 144             if (rc == 0) {
 145                 std += 2;
 146             }
 147         } else if (mode->xtra3 && xtra3) {
 148             xtra3[mode->xtra3] |= (1 << mode->bit);
 149         }
 150
 151         if (dta && mode->dta) {
 152             edid_ext_dta_mode(dta, mode->dta);
 153         }
 154     }
 155
 156     while (std < 54) {
 157         edid_std_mode(edid + std, 0, 0);
 158         std += 2;
 159     }
 160 }
 161
 162 static void edid_checksum(uint8_t *edid, size_t len)
 163 {
 164     uint32_t sum = 0;
 165     int i;
 166
 167     for (i = 0; i < len; i++) {
 168         sum += edid[i];
 169     }
 170     sum &= 0xff;
 171     if (sum) {
 172         edid[len] = 0x100 - sum;
 173     }
 174 }
 175
 176 static uint8_t *edid_desc_next(uint8_t *edid, uint8_t *dta, uint8_t *desc)
 177 {
 178     if (desc == NULL) {
 179         return NULL;
 180     }
 181     if (desc + 18 + 18 < edid + 127) {
 182         return desc + 18;
 183     }
 184     if (dta) {
 185         if (desc < edid + 127) {
 186             return dta + dta[2];
 187         }
 188         if (desc + 18 + 18 < dta + 127) {
 189             return desc + 18;
 190         }
 191     }
 192     return NULL;
 193 }
 194
 195 static void edid_desc_type(uint8_t *desc, uint8_t type)
 196 {
 197     desc[0] = 0;
 198     desc[1] = 0;
 199     desc[2] = 0;
 200     desc[3] = type;
 201     desc[4] = 0;
 202 }
 203
 204 static void edid_desc_text(uint8_t *desc, uint8_t type,
 205                            const char *text)
 206 {
 207     size_t len;
 208
 209     edid_desc_type(desc, type);
 210     memset(desc + 5, ' ', 13);
 211
 212     len = strlen(text);
 213     if (len > 12) {
 214         len = 12;
 215     }
 216     memcpy(desc + 5, text, len);
 217     desc[5 + len] = '\n';
 218 }
 219
 220 static void edid_desc_ranges(uint8_t *desc)
 221 {
 222     edid_desc_type(desc, 0xfd);
 223
 224     /* vertical (50 -> 125 Hz) */
 225     desc[5] =  50;
 226     desc[6] = 125;
 227
 228     /* horizontal (30 -> 160 kHz) */
 229     desc[7] =  30;
 230     desc[8] = 160;
 231
 232     /* max dot clock (2550 MHz) */
 233     desc[9] = 2550 / 10;
 234
 235     /* no extended timing information */
 236     desc[10] = 0x01;
 237
 238     /* padding */
 239     desc[11] = '\n';
 240     memset(desc + 12, ' ', 6);
 241 }
 242
 243 /* additional standard timings 3 */
 244 static void edid_desc_xtra3_std(uint8_t *desc)
 245 {
 246     edid_desc_type(desc, 0xf7);
 247     desc[5] = 10;
 248 }
 249
 250 static void edid_desc_dummy(uint8_t *desc)
 251 {
 252     edid_desc_type(desc, 0x10);
 253 }
 254
 255 static void edid_desc_timing(uint8_t *desc, uint32_t refresh_rate,
 256                              uint32_t xres, uint32_t yres,
 257                              uint32_t xmm, uint32_t ymm)
 258 {
 259     Timings timings;
 260     generate_timings(&timings, refresh_rate, xres, yres);
 261     stl_le_p(desc, timings.clock);
 262
 263     desc[2] = xres   & 0xff;
 264     desc[3] = timings.xblank & 0xff;
 265     desc[4] = (((xres   & 0xf00) >> 4) |
 266                ((timings.xblank & 0xf00) >> 8));
 267
 268     desc[5] = yres   & 0xff;
 269     desc[6] = timings.yblank & 0xff;
 270     desc[7] = (((yres   & 0xf00) >> 4) |
 271                ((timings.yblank & 0xf00) >> 8));
 272
 273     desc[8] = timings.xfront & 0xff;
 274     desc[9] = timings.xsync  & 0xff;
 275
 276     desc[10] = (((timings.yfront & 0x00f) << 4) |
 277                 ((timings.ysync  & 0x00f) << 0));
 278     desc[11] = (((timings.xfront & 0x300) >> 2) |
 279                 ((timings.xsync  & 0x300) >> 4) |
 280                 ((timings.yfront & 0x030) >> 2) |
 281                 ((timings.ysync  & 0x030) >> 4));
 282
 283     desc[12] = xmm & 0xff;
 284     desc[13] = ymm & 0xff;
 285     desc[14] = (((xmm & 0xf00) >> 4) |
 286                 ((ymm & 0xf00) >> 8));
 287
 288     desc[17] = 0x18;
 289 }
 290
 291 static uint32_t edid_to_10bit(float value)
 292 {
 293     return (uint32_t)(value * 1024 + 0.5);
 294 }
 295
 296 static void edid_colorspace(uint8_t *edid,
 297                             float rx, float ry,
 298                             float gx, float gy,
 299                             float bx, float by,
 300                             float wx, float wy)
 301 {
 302     uint32_t red_x   = edid_to_10bit(rx);
 303     uint32_t red_y   = edid_to_10bit(ry);
 304     uint32_t green_x = edid_to_10bit(gx);
 305     uint32_t green_y = edid_to_10bit(gy);
 306     uint32_t blue_x  = edid_to_10bit(bx);
 307     uint32_t blue_y  = edid_to_10bit(by);
 308     uint32_t white_x = edid_to_10bit(wx);
 309     uint32_t white_y = edid_to_10bit(wy);
 310
 311     edid[25] = (((red_x   & 0x03) << 6) |
 312                 ((red_y   & 0x03) << 4) |
 313                 ((green_x & 0x03) << 2) |
 314                 ((green_y & 0x03) << 0));
 315     edid[26] = (((blue_x  & 0x03) << 6) |
 316                 ((blue_y  & 0x03) << 4) |
 317                 ((white_x & 0x03) << 2) |
 318                 ((white_y & 0x03) << 0));
 319     edid[27] = red_x   >> 2;
 320     edid[28] = red_y   >> 2;
 321     edid[29] = green_x >> 2;
 322     edid[30] = green_y >> 2;
 323     edid[31] = blue_x  >> 2;
 324     edid[32] = blue_y  >> 2;
 325     edid[33] = white_x >> 2;
 326     edid[34] = white_y >> 2;
 327 }
 328
 329 static uint32_t qemu_edid_dpi_from_mm(uint32_t mm, uint32_t res)
 330 {
 331     return res * 254 / 10 / mm;
 332 }
 333
 334 uint32_t qemu_edid_dpi_to_mm(uint32_t dpi, uint32_t res)
 335 {
 336     return res * 254 / 10 / dpi;
 337 }
 338
 339 static void init_displayid(uint8_t *did)
 340 {
 341     did[0] = 0x70; /* display id extension */
 342     did[1] = 0x13; /* version 1.3 */
 343     did[2] = 4;    /* length */
 344     did[3] = 0x03; /* product type (0x03 == standalone display device) */
 345     edid_checksum(did + 1, did[2] + 4);
 346 }
 347
 348 static void qemu_displayid_generate(uint8_t *did, uint32_t refresh_rate,
 349                                     uint32_t xres, uint32_t yres,
 350                                     uint32_t xmm, uint32_t ymm)
 351 {
 352     Timings timings;
 353     generate_timings(&timings, refresh_rate, xres, yres);
 354
 355     did[0] = 0x70; /* display id extension */
 356     did[1] = 0x13; /* version 1.3 */
 357     did[2] = 23;   /* length */
 358     did[3] = 0x03; /* product type (0x03 == standalone display device) */
 359
 360     did[5] = 0x03; /* Detailed Timings Data Block */
 361     did[6] = 0x00; /* revision */
 362     did[7] = 0x14; /* block length */
 363
 364     did[8]  = timings.clock  & 0xff;
 365     did[9]  = (timings.clock & 0xff00) >> 8;
 366     did[10] = (timings.clock & 0xff0000) >> 16;
 367
 368     did[11] = 0x88; /* leave aspect ratio undefined */
 369
 370     stw_le_p(did + 12, 0xffff & (xres - 1));
 371     stw_le_p(did + 14, 0xffff & (timings.xblank - 1));
 372     stw_le_p(did + 16, 0xffff & (timings.xfront - 1));
 373     stw_le_p(did + 18, 0xffff & (timings.xsync - 1));
 374
 375     stw_le_p(did + 20, 0xffff & (yres - 1));
 376     stw_le_p(did + 22, 0xffff & (timings.yblank - 1));
 377     stw_le_p(did + 24, 0xffff & (timings.yfront - 1));
 378     stw_le_p(did + 26, 0xffff & (timings.ysync - 1));
 379
 380     edid_checksum(did + 1, did[2] + 4);
 381 }
 382
 383 void qemu_edid_generate(uint8_t *edid, size_t size,
 384                         qemu_edid_info *info)
 385 {
 386     uint8_t *desc = edid + 54;
 387     uint8_t *xtra3 = NULL;
 388     uint8_t *dta = NULL;
 389     uint8_t *did = NULL;
 390     uint32_t width_mm, height_mm;
 391     uint32_t refresh_rate = info->refresh_rate ? info->refresh_rate : 75000;
 392     uint32_t dpi = 100; /* if no width_mm/height_mm */
 393     uint32_t large_screen = 0;
 394
 395     /* =============== set defaults  =============== */
 396
 397     if (!info->vendor || strlen(info->vendor) != 3) {
 398         info->vendor = "RHT";
 399     }
 400     if (!info->name) {
 401         info->name = "QEMU Monitor";
 402     }
 403     if (!info->prefx) {
 404         info->prefx = 1024;
 405     }
 406     if (!info->prefy) {
 407         info->prefy = 768;
 408     }
 409     if (info->prefx >= 4096 || info->prefy >= 4096) {
 410         large_screen = 1;
 411     }
 412     if (info->width_mm && info->height_mm) {
 413         width_mm = info->width_mm;
 414         height_mm = info->height_mm;
 415         dpi = qemu_edid_dpi_from_mm(width_mm, info->prefx);
 416     } else {
 417         width_mm = qemu_edid_dpi_to_mm(dpi, info->prefx);
 418         height_mm = qemu_edid_dpi_to_mm(dpi, info->prefy);
 419     }
 420
 421     /* =============== extensions  =============== */
 422
 423     if (size >= 256) {
 424         dta = edid + 128;
 425         edid[126]++;
 426         edid_ext_dta(dta);
 427     }
 428
 429     if (size >= 384 && large_screen) {
 430         did = edid + 256;
 431         edid[126]++;
 432         init_displayid(did);
 433     }
 434
 435     /* =============== header information =============== */
 436
 437     /* fixed */
 438     edid[0] = 0x00;
 439     edid[1] = 0xff;
 440     edid[2] = 0xff;
 441     edid[3] = 0xff;
 442     edid[4] = 0xff;
 443     edid[5] = 0xff;
 444     edid[6] = 0xff;
 445     edid[7] = 0x00;
 446
 447     /* manufacturer id, product code, serial number */
 448     uint16_t vendor_id = ((((info->vendor[0] - '@') & 0x1f) << 10) |
 449                           (((info->vendor[1] - '@') & 0x1f) <<  5) |
 450                           (((info->vendor[2] - '@') & 0x1f) <<  0));
 451     uint16_t model_nr = 0x1234;
 452     uint32_t serial_nr = info->serial ? atoi(info->serial) : 0;
 453     stw_be_p(edid +  8, vendor_id);
 454     stw_le_p(edid + 10, model_nr);
 455     stl_le_p(edid + 12, serial_nr);
 456
 457     /* manufacture week and year */
 458     edid[16] = 42;
 459     edid[17] = 2014 - 1990;
 460
 461     /* edid version */
 462     edid[18] = 1;
 463     edid[19] = 4;
 464
 465
 466     /* =============== basic display parameters =============== */
 467
 468     /* video input: digital, 8bpc, displayport */
 469     edid[20] = 0xa5;
 470
 471     /* screen size: undefined */
 472     edid[21] = width_mm / 10;
 473     edid[22] = height_mm / 10;
 474
 475     /* display gamma: 2.2 */
 476     edid[23] = 220 - 100;
 477
 478     /* supported features bitmap: std sRGB, preferred timing */
 479     edid[24] = 0x06;
 480
 481
 482     /* =============== chromaticity coordinates =============== */
 483
 484     /* standard sRGB colorspace */
 485     edid_colorspace(edid,
 486                     0.6400, 0.3300,   /* red   */
 487                     0.3000, 0.6000,   /* green */
 488                     0.1500, 0.0600,   /* blue  */
 489                     0.3127, 0.3290);  /* white point  */
 490
 491     /* =============== established timing bitmap =============== */
 492     /* =============== standard timing information =============== */
 493
 494     /* both filled by edid_fill_modes() */
 495
 496
 497     /* =============== descriptor blocks =============== */
 498
 499     if (!large_screen) {
 500         /* The DTD section has only 12 bits to store the resolution */
 501         edid_desc_timing(desc, refresh_rate, info->prefx, info->prefy,
 502                          width_mm, height_mm);
 503         desc = edid_desc_next(edid, dta, desc);
 504     }
 505
 506     xtra3 = desc;
 507     edid_desc_xtra3_std(xtra3);
 508     desc = edid_desc_next(edid, dta, desc);
 509     edid_fill_modes(edid, xtra3, dta, info->maxx, info->maxy);
 510     /*
 511      * dta video data block is finished at thus point,
 512      * so dta descriptor offsets don't move any more.
 513      */
 514
 515     edid_desc_ranges(desc);
 516     desc = edid_desc_next(edid, dta, desc);
 517
 518     if (desc && info->name) {
 519         edid_desc_text(desc, 0xfc, info->name);
 520         desc = edid_desc_next(edid, dta, desc);
 521     }
 522
 523     if (desc && info->serial) {
 524         edid_desc_text(desc, 0xff, info->serial);
 525         desc = edid_desc_next(edid, dta, desc);
 526     }
 527
 528     while (desc) {
 529         edid_desc_dummy(desc);
 530         desc = edid_desc_next(edid, dta, desc);
 531     }
 532
 533     /* =============== display id extensions =============== */
 534
 535     if (did && large_screen) {
 536         qemu_displayid_generate(did, refresh_rate, info->prefx, info->prefy,
 537                                 width_mm, height_mm);
 538     }
 539
 540     /* =============== finish up =============== */
 541
 542     edid_checksum(edid, 127);
 543     if (dta) {
 544         edid_checksum(dta, 127);
 545     }
 546     if (did) {
 547         edid_checksum(did, 127);
 548     }
 549 }
 550
 551 size_t qemu_edid_size(uint8_t *edid)
 552 {
 553     uint32_t exts;
 554
 555     if (edid[0] != 0x00 ||
 556         edid[1] != 0xff) {
 557         /* doesn't look like a valid edid block */
 558         return 0;
 559     }
 560
 561     exts = edid[126];
 562     return 128 * (exts + 1);
 563 }