drivers/gpu/drm/i915/intel_crt.c

   1 /*
   2  * Copyright © 2006-2007 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
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *      Eric Anholt <eric@anholt.net>
  25  */
  26
  27 #include <linux/i2c.h>
  28 #include <linux/slab.h>
  29 #include "drmP.h"
  30 #include "drm.h"
  31 #include "drm_crtc.h"
  32 #include "drm_crtc_helper.h"
  33 #include "drm_edid.h"
  34 #include "intel_drv.h"
  35 #include "i915_drm.h"
  36 #include "i915_drv.h"
  37
  38 /* Here's the desired hotplug mode */
  39 #define ADPA_HOTPLUG_BITS (ADPA_CRT_HOTPLUG_PERIOD_128 |                \
  40                            ADPA_CRT_HOTPLUG_WARMUP_10MS |               \
  41                            ADPA_CRT_HOTPLUG_SAMPLE_4S |                 \
  42                            ADPA_CRT_HOTPLUG_VOLTAGE_50 |                \
  43                            ADPA_CRT_HOTPLUG_VOLREF_325MV |              \
  44                            ADPA_CRT_HOTPLUG_ENABLE)
  45
  46 struct intel_crt {
  47         struct intel_encoder base;
  48         bool force_hotplug_required;
  49 };
  50
  51 static struct intel_crt *intel_attached_crt(struct drm_connector *connector)
  52 {
  53         return container_of(intel_attached_encoder(connector),
  54                             struct intel_crt, base);
  55 }
  56
  57 static void intel_crt_dpms(struct drm_encoder *encoder, int mode)
  58 {
  59         struct drm_device *dev = encoder->dev;
  60         struct drm_i915_private *dev_priv = dev->dev_private;
  61         u32 temp, reg;
  62
  63         if (HAS_PCH_SPLIT(dev))
  64                 reg = PCH_ADPA;
  65         else
  66                 reg = ADPA;
  67
  68         temp = I915_READ(reg);
  69         temp &= ~(ADPA_HSYNC_CNTL_DISABLE | ADPA_VSYNC_CNTL_DISABLE);
  70         temp &= ~ADPA_DAC_ENABLE;
  71
  72         switch (mode) {
  73         case DRM_MODE_DPMS_ON:
  74                 temp |= ADPA_DAC_ENABLE;
  75                 break;
  76         case DRM_MODE_DPMS_STANDBY:
  77                 temp |= ADPA_DAC_ENABLE | ADPA_HSYNC_CNTL_DISABLE;
  78                 break;
  79         case DRM_MODE_DPMS_SUSPEND:
  80                 temp |= ADPA_DAC_ENABLE | ADPA_VSYNC_CNTL_DISABLE;
  81                 break;
  82         case DRM_MODE_DPMS_OFF:
  83                 temp |= ADPA_HSYNC_CNTL_DISABLE | ADPA_VSYNC_CNTL_DISABLE;
  84                 break;
  85         }
  86
  87         I915_WRITE(reg, temp);
  88 }
  89
  90 static int intel_crt_mode_valid(struct drm_connector *connector,
  91                                 struct drm_display_mode *mode)
  92 {
  93         struct drm_device *dev = connector->dev;
  94
  95         int max_clock = 0;
  96         if (mode->flags & DRM_MODE_FLAG_DBLSCAN)
  97                 return MODE_NO_DBLESCAN;
  98
  99         if (mode->clock < 25000)
 100                 return MODE_CLOCK_LOW;
 101
 102         if (IS_GEN2(dev))
 103                 max_clock = 350000;
 104         else
 105                 max_clock = 400000;
 106         if (mode->clock > max_clock)
 107                 return MODE_CLOCK_HIGH;
 108
 109         return MODE_OK;
 110 }
 111
 112 static bool intel_crt_mode_fixup(struct drm_encoder *encoder,
 113                                  struct drm_display_mode *mode,
 114                                  struct drm_display_mode *adjusted_mode)
 115 {
 116         return true;
 117 }
 118
 119 static void intel_crt_mode_set(struct drm_encoder *encoder,
 120                                struct drm_display_mode *mode,
 121                                struct drm_display_mode *adjusted_mode)
 122 {
 123
 124         struct drm_device *dev = encoder->dev;
 125         struct drm_crtc *crtc = encoder->crtc;
 126         struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 127         struct drm_i915_private *dev_priv = dev->dev_private;
 128         int dpll_md_reg;
 129         u32 adpa, dpll_md;
 130         u32 adpa_reg;
 131
 132         dpll_md_reg = DPLL_MD(intel_crtc->pipe);
 133
 134         if (HAS_PCH_SPLIT(dev))
 135                 adpa_reg = PCH_ADPA;
 136         else
 137                 adpa_reg = ADPA;
 138
 139         /*
 140          * Disable separate mode multiplier used when cloning SDVO to CRT
 141          * XXX this needs to be adjusted when we really are cloning
 142          */
 143         if (INTEL_INFO(dev)->gen >= 4 && !HAS_PCH_SPLIT(dev)) {
 144                 dpll_md = I915_READ(dpll_md_reg);
 145                 I915_WRITE(dpll_md_reg,
 146                            dpll_md & ~DPLL_MD_UDI_MULTIPLIER_MASK);
 147         }
 148
 149         adpa = ADPA_HOTPLUG_BITS;
 150         if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
 151                 adpa |= ADPA_HSYNC_ACTIVE_HIGH;
 152         if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
 153                 adpa |= ADPA_VSYNC_ACTIVE_HIGH;
 154
 155         /* For CPT allow 3 pipe config, for others just use A or B */
 156         if (HAS_PCH_CPT(dev))
 157                 adpa |= PORT_TRANS_SEL_CPT(intel_crtc->pipe);
 158         else if (intel_crtc->pipe == 0)
 159                 adpa |= ADPA_PIPE_A_SELECT;
 160         else
 161                 adpa |= ADPA_PIPE_B_SELECT;
 162
 163         if (!HAS_PCH_SPLIT(dev))
 164                 I915_WRITE(BCLRPAT(intel_crtc->pipe), 0);
 165
 166         I915_WRITE(adpa_reg, adpa);
 167 }
 168
 169 static bool intel_ironlake_crt_detect_hotplug(struct drm_connector *connector)
 170 {
 171         struct drm_device *dev = connector->dev;
 172         struct intel_crt *crt = intel_attached_crt(connector);
 173         struct drm_i915_private *dev_priv = dev->dev_private;
 174         u32 adpa;
 175         bool ret;
 176
 177         /* The first time through, trigger an explicit detection cycle */
 178         if (crt->force_hotplug_required) {
 179                 bool turn_off_dac = HAS_PCH_SPLIT(dev);
 180                 u32 save_adpa;
 181
 182                 crt->force_hotplug_required = 0;
 183
 184                 save_adpa = adpa = I915_READ(PCH_ADPA);
 185                 DRM_DEBUG_KMS("trigger hotplug detect cycle: adpa=0x%x\n", adpa);
 186
 187                 adpa |= ADPA_CRT_HOTPLUG_FORCE_TRIGGER;
 188                 if (turn_off_dac)
 189                         adpa &= ~ADPA_DAC_ENABLE;
 190
 191                 I915_WRITE(PCH_ADPA, adpa);
 192
 193                 if (wait_for((I915_READ(PCH_ADPA) & ADPA_CRT_HOTPLUG_FORCE_TRIGGER) == 0,
 194                              1000))
 195                         DRM_DEBUG_KMS("timed out waiting for FORCE_TRIGGER");
 196
 197                 if (turn_off_dac) {
 198                         I915_WRITE(PCH_ADPA, save_adpa);
 199                         POSTING_READ(PCH_ADPA);
 200                 }
 201         }
 202
 203         /* Check the status to see if both blue and green are on now */
 204         adpa = I915_READ(PCH_ADPA);
 205         if ((adpa & ADPA_CRT_HOTPLUG_MONITOR_MASK) != 0)
 206                 ret = true;
 207         else
 208                 ret = false;
 209         DRM_DEBUG_KMS("ironlake hotplug adpa=0x%x, result %d\n", adpa, ret);
 210
 211         return ret;
 212 }
 213
 214 /**
 215  * Uses CRT_HOTPLUG_EN and CRT_HOTPLUG_STAT to detect CRT presence.
 216  *
 217  * Not for i915G/i915GM
 218  *
 219  * \return true if CRT is connected.
 220  * \return false if CRT is disconnected.
 221  */
 222 static bool intel_crt_detect_hotplug(struct drm_connector *connector)
 223 {
 224         struct drm_device *dev = connector->dev;
 225         struct drm_i915_private *dev_priv = dev->dev_private;
 226         u32 hotplug_en, orig, stat;
 227         bool ret = false;
 228         int i, tries = 0;
 229
 230         if (HAS_PCH_SPLIT(dev))
 231                 return intel_ironlake_crt_detect_hotplug(connector);
 232
 233         /*
 234          * On 4 series desktop, CRT detect sequence need to be done twice
 235          * to get a reliable result.
 236          */
 237
 238         if (IS_G4X(dev) && !IS_GM45(dev))
 239                 tries = 2;
 240         else
 241                 tries = 1;
 242         hotplug_en = orig = I915_READ(PORT_HOTPLUG_EN);
 243         hotplug_en |= CRT_HOTPLUG_FORCE_DETECT;
 244
 245         for (i = 0; i < tries ; i++) {
 246                 /* turn on the FORCE_DETECT */
 247                 I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
 248                 /* wait for FORCE_DETECT to go off */
 249                 if (wait_for((I915_READ(PORT_HOTPLUG_EN) &
 250                               CRT_HOTPLUG_FORCE_DETECT) == 0,
 251                              1000))
 252                         DRM_DEBUG_KMS("timed out waiting for FORCE_DETECT to go off");
 253         }
 254
 255         stat = I915_READ(PORT_HOTPLUG_STAT);
 256         if ((stat & CRT_HOTPLUG_MONITOR_MASK) != CRT_HOTPLUG_MONITOR_NONE)
 257                 ret = true;
 258
 259         /* clear the interrupt we just generated, if any */
 260         I915_WRITE(PORT_HOTPLUG_STAT, CRT_HOTPLUG_INT_STATUS);
 261
 262         /* and put the bits back */
 263         I915_WRITE(PORT_HOTPLUG_EN, orig);
 264
 265         return ret;
 266 }
 267
 268 static bool intel_crt_detect_ddc(struct drm_connector *connector)
 269 {
 270         struct intel_crt *crt = intel_attached_crt(connector);
 271         struct drm_i915_private *dev_priv = crt->base.base.dev->dev_private;
 272
 273         /* CRT should always be at 0, but check anyway */
 274         if (crt->base.type != INTEL_OUTPUT_ANALOG)
 275                 return false;
 276
 277         if (intel_ddc_probe(&crt->base, dev_priv->crt_ddc_pin)) {
 278                 struct edid *edid;
 279                 bool is_digital = false;
 280
 281                 edid = drm_get_edid(connector,
 282                         &dev_priv->gmbus[dev_priv->crt_ddc_pin].adapter);
 283                 /*
 284                  * This may be a DVI-I connector with a shared DDC
 285                  * link between analog and digital outputs, so we
 286                  * have to check the EDID input spec of the attached device.
 287                  *
 288                  * On the other hand, what should we do if it is a broken EDID?
 289                  */
 290                 if (edid != NULL) {
 291                         is_digital = edid->input & DRM_EDID_INPUT_DIGITAL;
 292                         connector->display_info.raw_edid = NULL;
 293                         kfree(edid);
 294                 }
 295
 296                 if (!is_digital) {
 297                         DRM_DEBUG_KMS("CRT detected via DDC:0x50 [EDID]\n");
 298                         return true;
 299                 } else {
 300                         DRM_DEBUG_KMS("CRT not detected via DDC:0x50 [EDID reports a digital panel]\n");
 301                 }
 302         }
 303
 304         return false;
 305 }
 306
 307 static enum drm_connector_status
 308 intel_crt_load_detect(struct intel_crt *crt)
 309 {
 310         struct drm_device *dev = crt->base.base.dev;
 311         struct drm_i915_private *dev_priv = dev->dev_private;
 312         uint32_t pipe = to_intel_crtc(crt->base.base.crtc)->pipe;
 313         uint32_t save_bclrpat;
 314         uint32_t save_vtotal;
 315         uint32_t vtotal, vactive;
 316         uint32_t vsample;
 317         uint32_t vblank, vblank_start, vblank_end;
 318         uint32_t dsl;
 319         uint32_t bclrpat_reg;
 320         uint32_t vtotal_reg;
 321         uint32_t vblank_reg;
 322         uint32_t vsync_reg;
 323         uint32_t pipeconf_reg;
 324         uint32_t pipe_dsl_reg;
 325         uint8_t st00;
 326         enum drm_connector_status status;
 327
 328         DRM_DEBUG_KMS("starting load-detect on CRT\n");
 329
 330         bclrpat_reg = BCLRPAT(pipe);
 331         vtotal_reg = VTOTAL(pipe);
 332         vblank_reg = VBLANK(pipe);
 333         vsync_reg = VSYNC(pipe);
 334         pipeconf_reg = PIPECONF(pipe);
 335         pipe_dsl_reg = PIPEDSL(pipe);
 336
 337         save_bclrpat = I915_READ(bclrpat_reg);
 338         save_vtotal = I915_READ(vtotal_reg);
 339         vblank = I915_READ(vblank_reg);
 340
 341         vtotal = ((save_vtotal >> 16) & 0xfff) + 1;
 342         vactive = (save_vtotal & 0x7ff) + 1;
 343
 344         vblank_start = (vblank & 0xfff) + 1;
 345         vblank_end = ((vblank >> 16) & 0xfff) + 1;
 346
 347         /* Set the border color to purple. */
 348         I915_WRITE(bclrpat_reg, 0x500050);
 349
 350         if (!IS_GEN2(dev)) {
 351                 uint32_t pipeconf = I915_READ(pipeconf_reg);
 352                 I915_WRITE(pipeconf_reg, pipeconf | PIPECONF_FORCE_BORDER);
 353                 POSTING_READ(pipeconf_reg);
 354                 /* Wait for next Vblank to substitue
 355                  * border color for Color info */
 356                 intel_wait_for_vblank(dev, pipe);
 357                 st00 = I915_READ8(VGA_MSR_WRITE);
 358                 status = ((st00 & (1 << 4)) != 0) ?
 359                         connector_status_connected :
 360                         connector_status_disconnected;
 361
 362                 I915_WRITE(pipeconf_reg, pipeconf);
 363         } else {
 364                 bool restore_vblank = false;
 365                 int count, detect;
 366
 367                 /*
 368                 * If there isn't any border, add some.
 369                 * Yes, this will flicker
 370                 */
 371                 if (vblank_start <= vactive && vblank_end >= vtotal) {
 372                         uint32_t vsync = I915_READ(vsync_reg);
 373                         uint32_t vsync_start = (vsync & 0xffff) + 1;
 374
 375                         vblank_start = vsync_start;
 376                         I915_WRITE(vblank_reg,
 377                                    (vblank_start - 1) |
 378                                    ((vblank_end - 1) << 16));
 379                         restore_vblank = true;
 380                 }
 381                 /* sample in the vertical border, selecting the larger one */
 382                 if (vblank_start - vactive >= vtotal - vblank_end)
 383                         vsample = (vblank_start + vactive) >> 1;
 384                 else
 385                         vsample = (vtotal + vblank_end) >> 1;
 386
 387                 /*
 388                  * Wait for the border to be displayed
 389                  */
 390                 while (I915_READ(pipe_dsl_reg) >= vactive)
 391                         ;
 392                 while ((dsl = I915_READ(pipe_dsl_reg)) <= vsample)
 393                         ;
 394                 /*
 395                  * Watch ST00 for an entire scanline
 396                  */
 397                 detect = 0;
 398                 count = 0;
 399                 do {
 400                         count++;
 401                         /* Read the ST00 VGA status register */
 402                         st00 = I915_READ8(VGA_MSR_WRITE);
 403                         if (st00 & (1 << 4))
 404                                 detect++;
 405                 } while ((I915_READ(pipe_dsl_reg) == dsl));
 406
 407                 /* restore vblank if necessary */
 408                 if (restore_vblank)
 409                         I915_WRITE(vblank_reg, vblank);
 410                 /*
 411                  * If more than 3/4 of the scanline detected a monitor,
 412                  * then it is assumed to be present. This works even on i830,
 413                  * where there isn't any way to force the border color across
 414                  * the screen
 415                  */
 416                 status = detect * 4 > count * 3 ?
 417                          connector_status_connected :
 418                          connector_status_disconnected;
 419         }
 420
 421         /* Restore previous settings */
 422         I915_WRITE(bclrpat_reg, save_bclrpat);
 423
 424         return status;
 425 }
 426
 427 static enum drm_connector_status
 428 intel_crt_detect(struct drm_connector *connector, bool force)
 429 {
 430         struct drm_device *dev = connector->dev;
 431         struct intel_crt *crt = intel_attached_crt(connector);
 432         struct drm_crtc *crtc;
 433         enum drm_connector_status status;
 434
 435         if (I915_HAS_HOTPLUG(dev)) {
 436                 if (intel_crt_detect_hotplug(connector)) {
 437                         DRM_DEBUG_KMS("CRT detected via hotplug\n");
 438                         return connector_status_connected;
 439                 } else {
 440                         DRM_DEBUG_KMS("CRT not detected via hotplug\n");
 441                         return connector_status_disconnected;
 442                 }
 443         }
 444
 445         if (intel_crt_detect_ddc(connector))
 446                 return connector_status_connected;
 447
 448         if (!force)
 449                 return connector->status;
 450
 451         /* for pre-945g platforms use load detect */
 452         crtc = crt->base.base.crtc;
 453         if (crtc && crtc->enabled) {
 454                 status = intel_crt_load_detect(crt);
 455         } else {
 456                 struct intel_load_detect_pipe tmp;
 457
 458                 if (intel_get_load_detect_pipe(&crt->base, connector, NULL,
 459                                                &tmp)) {
 460                         if (intel_crt_detect_ddc(connector))
 461                                 status = connector_status_connected;
 462                         else
 463                                 status = intel_crt_load_detect(crt);
 464                         intel_release_load_detect_pipe(&crt->base, connector,
 465                                                        &tmp);
 466                 } else
 467                         status = connector_status_unknown;
 468         }
 469
 470         return status;
 471 }
 472
 473 static void intel_crt_destroy(struct drm_connector *connector)
 474 {
 475         drm_sysfs_connector_remove(connector);
 476         drm_connector_cleanup(connector);
 477         kfree(connector);
 478 }
 479
 480 static int intel_crt_get_modes(struct drm_connector *connector)
 481 {
 482         struct drm_device *dev = connector->dev;
 483         struct drm_i915_private *dev_priv = dev->dev_private;
 484         int ret;
 485
 486         ret = intel_ddc_get_modes(connector,
 487                                  &dev_priv->gmbus[dev_priv->crt_ddc_pin].adapter);
 488         if (ret || !IS_G4X(dev))
 489                 return ret;
 490
 491         /* Try to probe digital port for output in DVI-I -> VGA mode. */
 492         return intel_ddc_get_modes(connector,
 493                                    &dev_priv->gmbus[GMBUS_PORT_DPB].adapter);
 494 }
 495
 496 static int intel_crt_set_property(struct drm_connector *connector,
 497                                   struct drm_property *property,
 498                                   uint64_t value)
 499 {
 500         return 0;
 501 }
 502
 503 static void intel_crt_reset(struct drm_connector *connector)
 504 {
 505         struct drm_device *dev = connector->dev;
 506         struct intel_crt *crt = intel_attached_crt(connector);
 507
 508         if (HAS_PCH_SPLIT(dev))
 509                 crt->force_hotplug_required = 1;
 510 }
 511
 512 /*
 513  * Routines for controlling stuff on the analog port
 514  */
 515
 516 static const struct drm_encoder_helper_funcs intel_crt_helper_funcs = {
 517         .dpms = intel_crt_dpms,
 518         .mode_fixup = intel_crt_mode_fixup,
 519         .prepare = intel_encoder_prepare,
 520         .commit = intel_encoder_commit,
 521         .mode_set = intel_crt_mode_set,
 522 };
 523
 524 static const struct drm_connector_funcs intel_crt_connector_funcs = {
 525         .reset = intel_crt_reset,
 526         .dpms = drm_helper_connector_dpms,
 527         .detect = intel_crt_detect,
 528         .fill_modes = drm_helper_probe_single_connector_modes,
 529         .destroy = intel_crt_destroy,
 530         .set_property = intel_crt_set_property,
 531 };
 532
 533 static const struct drm_connector_helper_funcs intel_crt_connector_helper_funcs = {
 534         .mode_valid = intel_crt_mode_valid,
 535         .get_modes = intel_crt_get_modes,
 536         .best_encoder = intel_best_encoder,
 537 };
 538
 539 static const struct drm_encoder_funcs intel_crt_enc_funcs = {
 540         .destroy = intel_encoder_destroy,
 541 };
 542
 543 void intel_crt_init(struct drm_device *dev)
 544 {
 545         struct drm_connector *connector;
 546         struct intel_crt *crt;
 547         struct intel_connector *intel_connector;
 548         struct drm_i915_private *dev_priv = dev->dev_private;
 549
 550         crt = kzalloc(sizeof(struct intel_crt), GFP_KERNEL);
 551         if (!crt)
 552                 return;
 553
 554         intel_connector = kzalloc(sizeof(struct intel_connector), GFP_KERNEL);
 555         if (!intel_connector) {
 556                 kfree(crt);
 557                 return;
 558         }
 559
 560         connector = &intel_connector->base;
 561         drm_connector_init(dev, &intel_connector->base,
 562                            &intel_crt_connector_funcs, DRM_MODE_CONNECTOR_VGA);
 563
 564         drm_encoder_init(dev, &crt->base.base, &intel_crt_enc_funcs,
 565                          DRM_MODE_ENCODER_DAC);
 566
 567         intel_connector_attach_encoder(intel_connector, &crt->base);
 568
 569         crt->base.type = INTEL_OUTPUT_ANALOG;
 570         crt->base.clone_mask = (1 << INTEL_SDVO_NON_TV_CLONE_BIT |
 571                                 1 << INTEL_ANALOG_CLONE_BIT |
 572                                 1 << INTEL_SDVO_LVDS_CLONE_BIT);
 573         crt->base.crtc_mask = (1 << 0) | (1 << 1);
 574         connector->interlace_allowed = 1;
 575         connector->doublescan_allowed = 0;
 576
 577         drm_encoder_helper_add(&crt->base.base, &intel_crt_helper_funcs);
 578         drm_connector_helper_add(connector, &intel_crt_connector_helper_funcs);
 579
 580         drm_sysfs_connector_add(connector);
 581
 582         if (I915_HAS_HOTPLUG(dev))
 583                 connector->polled = DRM_CONNECTOR_POLL_HPD;
 584         else
 585                 connector->polled = DRM_CONNECTOR_POLL_CONNECT;
 586
 587         /*
 588          * Configure the automatic hotplug detection stuff
 589          */
 590         crt->force_hotplug_required = 0;
 591         if (HAS_PCH_SPLIT(dev)) {
 592                 u32 adpa;
 593
 594                 adpa = I915_READ(PCH_ADPA);
 595                 adpa &= ~ADPA_CRT_HOTPLUG_MASK;
 596                 adpa |= ADPA_HOTPLUG_BITS;
 597                 I915_WRITE(PCH_ADPA, adpa);
 598                 POSTING_READ(PCH_ADPA);
 599
 600                 DRM_DEBUG_KMS("pch crt adpa set to 0x%x\n", adpa);
 601                 crt->force_hotplug_required = 1;
 602         }
 603
 604         dev_priv->hotplug_supported_mask |= CRT_HOTPLUG_INT_STATUS;
 605 }