drivers/gpu/drm/i915/intel_bios.c

   1 /*
   2  * Copyright © 2006 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  21  * SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27 #include "drmP.h"
  28 #include "drm.h"
  29 #include "i915_drm.h"
  30 #include "i915_drv.h"
  31 #include "intel_bios.h"
  32
  33 #define SLAVE_ADDR1     0x70
  34 #define SLAVE_ADDR2     0x72
  35
  36 static int panel_type;
  37
  38 static void *
  39 find_section(struct bdb_header *bdb, int section_id)
  40 {
  41         u8 *base = (u8 *)bdb;
  42         int index = 0;
  43         u16 total, current_size;
  44         u8 current_id;
  45
  46         /* skip to first section */
  47         index += bdb->header_size;
  48         total = bdb->bdb_size;
  49
  50         /* walk the sections looking for section_id */
  51         while (index < total) {
  52                 current_id = *(base + index);
  53                 index++;
  54                 current_size = *((u16 *)(base + index));
  55                 index += 2;
  56                 if (current_id == section_id)
  57                         return base + index;
  58                 index += current_size;
  59         }
  60
  61         return NULL;
  62 }
  63
  64 static u16
  65 get_blocksize(void *p)
  66 {
  67         u16 *block_ptr, block_size;
  68
  69         block_ptr = (u16 *)((char *)p - 2);
  70         block_size = *block_ptr;
  71         return block_size;
  72 }
  73
  74 static void
  75 fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
  76                         struct lvds_dvo_timing *dvo_timing)
  77 {
  78         panel_fixed_mode->hdisplay = (dvo_timing->hactive_hi << 8) |
  79                 dvo_timing->hactive_lo;
  80         panel_fixed_mode->hsync_start = panel_fixed_mode->hdisplay +
  81                 ((dvo_timing->hsync_off_hi << 8) | dvo_timing->hsync_off_lo);
  82         panel_fixed_mode->hsync_end = panel_fixed_mode->hsync_start +
  83                 dvo_timing->hsync_pulse_width;
  84         panel_fixed_mode->htotal = panel_fixed_mode->hdisplay +
  85                 ((dvo_timing->hblank_hi << 8) | dvo_timing->hblank_lo);
  86
  87         panel_fixed_mode->vdisplay = (dvo_timing->vactive_hi << 8) |
  88                 dvo_timing->vactive_lo;
  89         panel_fixed_mode->vsync_start = panel_fixed_mode->vdisplay +
  90                 dvo_timing->vsync_off;
  91         panel_fixed_mode->vsync_end = panel_fixed_mode->vsync_start +
  92                 dvo_timing->vsync_pulse_width;
  93         panel_fixed_mode->vtotal = panel_fixed_mode->vdisplay +
  94                 ((dvo_timing->vblank_hi << 8) | dvo_timing->vblank_lo);
  95         panel_fixed_mode->clock = dvo_timing->clock * 10;
  96         panel_fixed_mode->type = DRM_MODE_TYPE_PREFERRED;
  97
  98         if (dvo_timing->hsync_positive)
  99                 panel_fixed_mode->flags |= DRM_MODE_FLAG_PHSYNC;
 100         else
 101                 panel_fixed_mode->flags |= DRM_MODE_FLAG_NHSYNC;
 102
 103         if (dvo_timing->vsync_positive)
 104                 panel_fixed_mode->flags |= DRM_MODE_FLAG_PVSYNC;
 105         else
 106                 panel_fixed_mode->flags |= DRM_MODE_FLAG_NVSYNC;
 107
 108         /* Some VBTs have bogus h/vtotal values */
 109         if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal)
 110                 panel_fixed_mode->htotal = panel_fixed_mode->hsync_end + 1;
 111         if (panel_fixed_mode->vsync_end > panel_fixed_mode->vtotal)
 112                 panel_fixed_mode->vtotal = panel_fixed_mode->vsync_end + 1;
 113
 114         drm_mode_set_name(panel_fixed_mode);
 115 }
 116
 117 /* Try to find integrated panel data */
 118 static void
 119 parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 120                             struct bdb_header *bdb)
 121 {
 122         struct bdb_lvds_options *lvds_options;
 123         struct bdb_lvds_lfp_data *lvds_lfp_data;
 124         struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
 125         struct bdb_lvds_lfp_data_entry *entry;
 126         struct lvds_dvo_timing *dvo_timing;
 127         struct drm_display_mode *panel_fixed_mode;
 128         int lfp_data_size, dvo_timing_offset;
 129         int i, temp_downclock;
 130         struct drm_display_mode *temp_mode;
 131
 132         lvds_options = find_section(bdb, BDB_LVDS_OPTIONS);
 133         if (!lvds_options)
 134                 return;
 135
 136         dev_priv->lvds_dither = lvds_options->pixel_dither;
 137         if (lvds_options->panel_type == 0xff)
 138                 return;
 139
 140         panel_type = lvds_options->panel_type;
 141
 142         lvds_lfp_data = find_section(bdb, BDB_LVDS_LFP_DATA);
 143         if (!lvds_lfp_data)
 144                 return;
 145
 146         lvds_lfp_data_ptrs = find_section(bdb, BDB_LVDS_LFP_DATA_PTRS);
 147         if (!lvds_lfp_data_ptrs)
 148                 return;
 149
 150         dev_priv->lvds_vbt = 1;
 151
 152         lfp_data_size = lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
 153                 lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
 154         entry = (struct bdb_lvds_lfp_data_entry *)
 155                 ((uint8_t *)lvds_lfp_data->data + (lfp_data_size *
 156                                                    lvds_options->panel_type));
 157         dvo_timing_offset = lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
 158                 lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;
 159
 160         /*
 161          * the size of fp_timing varies on the different platform.
 162          * So calculate the DVO timing relative offset in LVDS data
 163          * entry to get the DVO timing entry
 164          */
 165         dvo_timing = (struct lvds_dvo_timing *)
 166                         ((unsigned char *)entry + dvo_timing_offset);
 167
 168         panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);
 169         if (!panel_fixed_mode)
 170                 return;
 171
 172         fill_detail_timing_data(panel_fixed_mode, dvo_timing);
 173
 174         dev_priv->lfp_lvds_vbt_mode = panel_fixed_mode;
 175
 176         DRM_DEBUG_KMS("Found panel mode in BIOS VBT tables:\n");
 177         drm_mode_debug_printmodeline(panel_fixed_mode);
 178
 179         temp_mode = kzalloc(sizeof(*temp_mode), GFP_KERNEL);
 180         temp_downclock = panel_fixed_mode->clock;
 181         /*
 182          * enumerate the LVDS panel timing info entry in VBT to check whether
 183          * the LVDS downclock is found.
 184          */
 185         for (i = 0; i < 16; i++) {
 186                 entry = (struct bdb_lvds_lfp_data_entry *)
 187                         ((uint8_t *)lvds_lfp_data->data + (lfp_data_size * i));
 188                 dvo_timing = (struct lvds_dvo_timing *)
 189                         ((unsigned char *)entry + dvo_timing_offset);
 190
 191                 fill_detail_timing_data(temp_mode, dvo_timing);
 192
 193                 if (temp_mode->hdisplay == panel_fixed_mode->hdisplay &&
 194                 temp_mode->hsync_start == panel_fixed_mode->hsync_start &&
 195                 temp_mode->hsync_end == panel_fixed_mode->hsync_end &&
 196                 temp_mode->htotal == panel_fixed_mode->htotal &&
 197                 temp_mode->vdisplay == panel_fixed_mode->vdisplay &&
 198                 temp_mode->vsync_start == panel_fixed_mode->vsync_start &&
 199                 temp_mode->vsync_end == panel_fixed_mode->vsync_end &&
 200                 temp_mode->vtotal == panel_fixed_mode->vtotal &&
 201                 temp_mode->clock < temp_downclock) {
 202                         /*
 203                          * downclock is already found. But we expect
 204                          * to find the lower downclock.
 205                          */
 206                         temp_downclock = temp_mode->clock;
 207                 }
 208                 /* clear it to zero */
 209                 memset(temp_mode, 0, sizeof(*temp_mode));
 210         }
 211         kfree(temp_mode);
 212         if (temp_downclock < panel_fixed_mode->clock &&
 213             i915_lvds_downclock) {
 214                 dev_priv->lvds_downclock_avail = 1;
 215                 dev_priv->lvds_downclock = temp_downclock;
 216                 DRM_DEBUG_KMS("LVDS downclock is found in VBT. ",
 217                                 "Normal Clock %dKHz, downclock %dKHz\n",
 218                                 temp_downclock, panel_fixed_mode->clock);
 219         }
 220         return;
 221 }
 222
 223 /* Try to find sdvo panel data */
 224 static void
 225 parse_sdvo_panel_data(struct drm_i915_private *dev_priv,
 226                       struct bdb_header *bdb)
 227 {
 228         struct bdb_sdvo_lvds_options *sdvo_lvds_options;
 229         struct lvds_dvo_timing *dvo_timing;
 230         struct drm_display_mode *panel_fixed_mode;
 231
 232         sdvo_lvds_options = find_section(bdb, BDB_SDVO_LVDS_OPTIONS);
 233         if (!sdvo_lvds_options)
 234                 return;
 235
 236         dvo_timing = find_section(bdb, BDB_SDVO_PANEL_DTDS);
 237         if (!dvo_timing)
 238                 return;
 239
 240         panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);
 241
 242         if (!panel_fixed_mode)
 243                 return;
 244
 245         fill_detail_timing_data(panel_fixed_mode,
 246                         dvo_timing + sdvo_lvds_options->panel_type);
 247
 248         dev_priv->sdvo_lvds_vbt_mode = panel_fixed_mode;
 249
 250         return;
 251 }
 252
 253 static void
 254 parse_general_features(struct drm_i915_private *dev_priv,
 255                        struct bdb_header *bdb)
 256 {
 257         struct drm_device *dev = dev_priv->dev;
 258         struct bdb_general_features *general;
 259
 260         general = find_section(bdb, BDB_GENERAL_FEATURES);
 261         if (general) {
 262                 dev_priv->int_tv_support = general->int_tv_support;
 263                 dev_priv->int_crt_support = general->int_crt_support;
 264                 dev_priv->lvds_use_ssc = general->enable_ssc;
 265
 266                 if (dev_priv->lvds_use_ssc) {
 267                         if (IS_I85X(dev_priv->dev))
 268                                 dev_priv->lvds_ssc_freq =
 269                                         general->ssc_freq ? 66 : 48;
 270                         else if (IS_IRONLAKE(dev_priv->dev) || IS_GEN6(dev))
 271                                 dev_priv->lvds_ssc_freq =
 272                                         general->ssc_freq ? 100 : 120;
 273                         else
 274                                 dev_priv->lvds_ssc_freq =
 275                                         general->ssc_freq ? 100 : 96;
 276                 }
 277         }
 278 }
 279
 280 static void
 281 parse_general_definitions(struct drm_i915_private *dev_priv,
 282                           struct bdb_header *bdb)
 283 {
 284         struct bdb_general_definitions *general;
 285
 286         general = find_section(bdb, BDB_GENERAL_DEFINITIONS);
 287         if (general) {
 288                 u16 block_size = get_blocksize(general);
 289                 if (block_size >= sizeof(*general)) {
 290                         int bus_pin = general->crt_ddc_gmbus_pin;
 291                         DRM_DEBUG_KMS("crt_ddc_bus_pin: %d\n", bus_pin);
 292                         if (bus_pin >= 1 && bus_pin <= 6)
 293                                 dev_priv->crt_ddc_pin = bus_pin;
 294                 } else {
 295                         DRM_DEBUG_KMS("BDB_GD too small (%d). Invalid.\n",
 296                                   block_size);
 297                 }
 298         }
 299 }
 300
 301 static void
 302 parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
 303                           struct bdb_header *bdb)
 304 {
 305         struct sdvo_device_mapping *p_mapping;
 306         struct bdb_general_definitions *p_defs;
 307         struct child_device_config *p_child;
 308         int i, child_device_num, count;
 309         u16     block_size;
 310
 311         p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
 312         if (!p_defs) {
 313                 DRM_DEBUG_KMS("No general definition block is found, unable to construct sdvo mapping.\n");
 314                 return;
 315         }
 316         /* judge whether the size of child device meets the requirements.
 317          * If the child device size obtained from general definition block
 318          * is different with sizeof(struct child_device_config), skip the
 319          * parsing of sdvo device info
 320          */
 321         if (p_defs->child_dev_size != sizeof(*p_child)) {
 322                 /* different child dev size . Ignore it */
 323                 DRM_DEBUG_KMS("different child size is found. Invalid.\n");
 324                 return;
 325         }
 326         /* get the block size of general definitions */
 327         block_size = get_blocksize(p_defs);
 328         /* get the number of child device */
 329         child_device_num = (block_size - sizeof(*p_defs)) /
 330                                 sizeof(*p_child);
 331         count = 0;
 332         for (i = 0; i < child_device_num; i++) {
 333                 p_child = &(p_defs->devices[i]);
 334                 if (!p_child->device_type) {
 335                         /* skip the device block if device type is invalid */
 336                         continue;
 337                 }
 338                 if (p_child->slave_addr != SLAVE_ADDR1 &&
 339                         p_child->slave_addr != SLAVE_ADDR2) {
 340                         /*
 341                          * If the slave address is neither 0x70 nor 0x72,
 342                          * it is not a SDVO device. Skip it.
 343                          */
 344                         continue;
 345                 }
 346                 if (p_child->dvo_port != DEVICE_PORT_DVOB &&
 347                         p_child->dvo_port != DEVICE_PORT_DVOC) {
 348                         /* skip the incorrect SDVO port */
 349                         DRM_DEBUG_KMS("Incorrect SDVO port. Skip it \n");
 350                         continue;
 351                 }
 352                 DRM_DEBUG_KMS("the SDVO device with slave addr %2x is found on"
 353                                 " %s port\n",
 354                                 p_child->slave_addr,
 355                                 (p_child->dvo_port == DEVICE_PORT_DVOB) ?
 356                                         "SDVOB" : "SDVOC");
 357                 p_mapping = &(dev_priv->sdvo_mappings[p_child->dvo_port - 1]);
 358                 if (!p_mapping->initialized) {
 359                         p_mapping->dvo_port = p_child->dvo_port;
 360                         p_mapping->slave_addr = p_child->slave_addr;
 361                         p_mapping->dvo_wiring = p_child->dvo_wiring;
 362                         p_mapping->ddc_pin = p_child->ddc_pin;
 363                         p_mapping->i2c_pin = p_child->i2c_pin;
 364                         p_mapping->i2c_speed = p_child->i2c_speed;
 365                         p_mapping->initialized = 1;
 366                         DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d, i2c_speed=%d\n",
 367                                       p_mapping->dvo_port,
 368                                       p_mapping->slave_addr,
 369                                       p_mapping->dvo_wiring,
 370                                       p_mapping->ddc_pin,
 371                                       p_mapping->i2c_pin,
 372                                       p_mapping->i2c_speed);
 373                 } else {
 374                         DRM_DEBUG_KMS("Maybe one SDVO port is shared by "
 375                                          "two SDVO device.\n");
 376                 }
 377                 if (p_child->slave2_addr) {
 378                         /* Maybe this is a SDVO device with multiple inputs */
 379                         /* And the mapping info is not added */
 380                         DRM_DEBUG_KMS("there exists the slave2_addr. Maybe this"
 381                                 " is a SDVO device with multiple inputs.\n");
 382                 }
 383                 count++;
 384         }
 385
 386         if (!count) {
 387                 /* No SDVO device info is found */
 388                 DRM_DEBUG_KMS("No SDVO device info is found in VBT\n");
 389         }
 390         return;
 391 }
 392
 393 static void
 394 parse_driver_features(struct drm_i915_private *dev_priv,
 395                        struct bdb_header *bdb)
 396 {
 397         struct drm_device *dev = dev_priv->dev;
 398         struct bdb_driver_features *driver;
 399
 400         driver = find_section(bdb, BDB_DRIVER_FEATURES);
 401         if (!driver)
 402                 return;
 403
 404         if (SUPPORTS_EDP(dev) &&
 405             driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
 406                 dev_priv->edp.support = 1;
 407
 408         if (driver->dual_frequency)
 409                 dev_priv->render_reclock_avail = true;
 410 }
 411
 412 static void
 413 parse_edp(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
 414 {
 415         struct bdb_edp *edp;
 416
 417         edp = find_section(bdb, BDB_EDP);
 418         if (!edp) {
 419                 if (SUPPORTS_EDP(dev_priv->dev) && dev_priv->edp.support) {
 420                         DRM_DEBUG_KMS("No eDP BDB found but eDP panel "
 421                                       "supported, assume %dbpp panel color "
 422                                       "depth.\n",
 423                                       dev_priv->edp.bpp);
 424                 }
 425                 return;
 426         }
 427
 428         switch ((edp->color_depth >> (panel_type * 2)) & 3) {
 429         case EDP_18BPP:
 430                 dev_priv->edp.bpp = 18;
 431                 break;
 432         case EDP_24BPP:
 433                 dev_priv->edp.bpp = 24;
 434                 break;
 435         case EDP_30BPP:
 436                 dev_priv->edp.bpp = 30;
 437                 break;
 438         }
 439
 440         dev_priv->edp.rate = edp->link_params[panel_type].rate;
 441         dev_priv->edp.lanes = edp->link_params[panel_type].lanes;
 442         dev_priv->edp.preemphasis = edp->link_params[panel_type].preemphasis;
 443         dev_priv->edp.vswing = edp->link_params[panel_type].vswing;
 444
 445         DRM_DEBUG_KMS("eDP vBIOS settings: bpp=%d, rate=%d, lanes=%d, preemphasis=%d, vswing=%d\n",
 446                       dev_priv->edp.bpp,
 447                       dev_priv->edp.rate,
 448                       dev_priv->edp.lanes,
 449                       dev_priv->edp.preemphasis,
 450                       dev_priv->edp.vswing);
 451
 452         dev_priv->edp.initialized = true;
 453 }
 454
 455 static void
 456 parse_device_mapping(struct drm_i915_private *dev_priv,
 457                        struct bdb_header *bdb)
 458 {
 459         struct bdb_general_definitions *p_defs;
 460         struct child_device_config *p_child, *child_dev_ptr;
 461         int i, child_device_num, count;
 462         u16     block_size;
 463
 464         p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
 465         if (!p_defs) {
 466                 DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
 467                 return;
 468         }
 469         /* judge whether the size of child device meets the requirements.
 470          * If the child device size obtained from general definition block
 471          * is different with sizeof(struct child_device_config), skip the
 472          * parsing of sdvo device info
 473          */
 474         if (p_defs->child_dev_size != sizeof(*p_child)) {
 475                 /* different child dev size . Ignore it */
 476                 DRM_DEBUG_KMS("different child size is found. Invalid.\n");
 477                 return;
 478         }
 479         /* get the block size of general definitions */
 480         block_size = get_blocksize(p_defs);
 481         /* get the number of child device */
 482         child_device_num = (block_size - sizeof(*p_defs)) /
 483                                 sizeof(*p_child);
 484         count = 0;
 485         /* get the number of child device that is present */
 486         for (i = 0; i < child_device_num; i++) {
 487                 p_child = &(p_defs->devices[i]);
 488                 if (!p_child->device_type) {
 489                         /* skip the device block if device type is invalid */
 490                         continue;
 491                 }
 492                 count++;
 493         }
 494         if (!count) {
 495                 DRM_DEBUG_KMS("no child dev is parsed from VBT \n");
 496                 return;
 497         }
 498         dev_priv->child_dev = kzalloc(sizeof(*p_child) * count, GFP_KERNEL);
 499         if (!dev_priv->child_dev) {
 500                 DRM_DEBUG_KMS("No memory space for child device\n");
 501                 return;
 502         }
 503
 504         dev_priv->child_dev_num = count;
 505         count = 0;
 506         for (i = 0; i < child_device_num; i++) {
 507                 p_child = &(p_defs->devices[i]);
 508                 if (!p_child->device_type) {
 509                         /* skip the device block if device type is invalid */
 510                         continue;
 511                 }
 512                 child_dev_ptr = dev_priv->child_dev + count;
 513                 count++;
 514                 memcpy((void *)child_dev_ptr, (void *)p_child,
 515                                         sizeof(*p_child));
 516         }
 517         return;
 518 }
 519
 520 static void
 521 init_vbt_defaults(struct drm_i915_private *dev_priv)
 522 {
 523         dev_priv->crt_ddc_pin = GMBUS_PORT_VGADDC;
 524
 525         /* LFP panel data */
 526         dev_priv->lvds_dither = 1;
 527         dev_priv->lvds_vbt = 0;
 528
 529         /* SDVO panel data */
 530         dev_priv->sdvo_lvds_vbt_mode = NULL;
 531
 532         /* general features */
 533         dev_priv->int_tv_support = 1;
 534         dev_priv->int_crt_support = 1;
 535         dev_priv->lvds_use_ssc = 0;
 536
 537         /* eDP data */
 538         dev_priv->edp.bpp = 18;
 539 }
 540
 541 /**
 542  * intel_init_bios - initialize VBIOS settings & find VBT
 543  * @dev: DRM device
 544  *
 545  * Loads the Video BIOS and checks that the VBT exists.  Sets scratch registers
 546  * to appropriate values.
 547  *
 548  * Returns 0 on success, nonzero on failure.
 549  */
 550 bool
 551 intel_init_bios(struct drm_device *dev)
 552 {
 553         struct drm_i915_private *dev_priv = dev->dev_private;
 554         struct pci_dev *pdev = dev->pdev;
 555         struct bdb_header *bdb = NULL;
 556         u8 __iomem *bios = NULL;
 557
 558         init_vbt_defaults(dev_priv);
 559
 560         /* XXX Should this validation be moved to intel_opregion.c? */
 561         if (dev_priv->opregion.vbt) {
 562                 struct vbt_header *vbt = dev_priv->opregion.vbt;
 563                 if (memcmp(vbt->signature, "$VBT", 4) == 0) {
 564                         DRM_DEBUG_DRIVER("Using VBT from OpRegion: %20s\n",
 565                                          vbt->signature);
 566                         bdb = (struct bdb_header *)((char *)vbt + vbt->bdb_offset);
 567                 } else
 568                         dev_priv->opregion.vbt = NULL;
 569         }
 570
 571         if (bdb == NULL) {
 572                 struct vbt_header *vbt = NULL;
 573                 size_t size;
 574                 int i;
 575
 576                 bios = pci_map_rom(pdev, &size);
 577                 if (!bios)
 578                         return -1;
 579
 580                 /* Scour memory looking for the VBT signature */
 581                 for (i = 0; i + 4 < size; i++) {
 582                         if (!memcmp(bios + i, "$VBT", 4)) {
 583                                 vbt = (struct vbt_header *)(bios + i);
 584                                 break;
 585                         }
 586                 }
 587
 588                 if (!vbt) {
 589                         DRM_ERROR("VBT signature missing\n");
 590                         pci_unmap_rom(pdev, bios);
 591                         return -1;
 592                 }
 593
 594                 bdb = (struct bdb_header *)(bios + i + vbt->bdb_offset);
 595         }
 596
 597         /* Grab useful general definitions */
 598         parse_general_features(dev_priv, bdb);
 599         parse_general_definitions(dev_priv, bdb);
 600         parse_lfp_panel_data(dev_priv, bdb);
 601         parse_sdvo_panel_data(dev_priv, bdb);
 602         parse_sdvo_device_mapping(dev_priv, bdb);
 603         parse_device_mapping(dev_priv, bdb);
 604         parse_driver_features(dev_priv, bdb);
 605         parse_edp(dev_priv, bdb);
 606
 607         if (bios)
 608                 pci_unmap_rom(pdev, bios);
 609
 610         return 0;
 611 }