drivers/gpu/drm/i915/intel_lvds.c

   1 /*
   2  * Copyright © 2006-2007 Intel Corporation
   3  * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *      Eric Anholt <eric@anholt.net>
  26  *      Dave Airlie <airlied@linux.ie>
  27  *      Jesse Barnes <jesse.barnes@intel.com>
  28  */
  29
  30 #include <linux/dmi.h>
  31 #include <linux/i2c.h>
  32 #include "drmP.h"
  33 #include "drm.h"
  34 #include "drm_crtc.h"
  35 #include "drm_edid.h"
  36 #include "intel_drv.h"
  37 #include "i915_drm.h"
  38 #include "i915_drv.h"
  39
  40 #define I915_LVDS "i915_lvds"
  41
  42 /**
  43  * Sets the backlight level.
  44  *
  45  * \param level backlight level, from 0 to intel_lvds_get_max_backlight().
  46  */
  47 static void intel_lvds_set_backlight(struct drm_device *dev, int level)
  48 {
  49         struct drm_i915_private *dev_priv = dev->dev_private;
  50         u32 blc_pwm_ctl, reg;
  51
  52         if (IS_IGDNG(dev))
  53                 reg = BLC_PWM_CPU_CTL;
  54         else
  55                 reg = BLC_PWM_CTL;
  56
  57         blc_pwm_ctl = I915_READ(reg) & ~BACKLIGHT_DUTY_CYCLE_MASK;
  58         I915_WRITE(reg, (blc_pwm_ctl |
  59                                  (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
  60 }
  61
  62 /**
  63  * Returns the maximum level of the backlight duty cycle field.
  64  */
  65 static u32 intel_lvds_get_max_backlight(struct drm_device *dev)
  66 {
  67         struct drm_i915_private *dev_priv = dev->dev_private;
  68         u32 reg;
  69
  70         if (IS_IGDNG(dev))
  71                 reg = BLC_PWM_PCH_CTL2;
  72         else
  73                 reg = BLC_PWM_CTL;
  74
  75         return ((I915_READ(reg) & BACKLIGHT_MODULATION_FREQ_MASK) >>
  76                 BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
  77 }
  78
  79 /**
  80  * Sets the power state for the panel.
  81  */
  82 static void intel_lvds_set_power(struct drm_device *dev, bool on)
  83 {
  84         struct drm_i915_private *dev_priv = dev->dev_private;
  85         u32 pp_status, ctl_reg, status_reg;
  86
  87         if (IS_IGDNG(dev)) {
  88                 ctl_reg = PCH_PP_CONTROL;
  89                 status_reg = PCH_PP_STATUS;
  90         } else {
  91                 ctl_reg = PP_CONTROL;
  92                 status_reg = PP_STATUS;
  93         }
  94
  95         if (on) {
  96                 I915_WRITE(ctl_reg, I915_READ(ctl_reg) |
  97                            POWER_TARGET_ON);
  98                 do {
  99                         pp_status = I915_READ(status_reg);
 100                 } while ((pp_status & PP_ON) == 0);
 101
 102                 intel_lvds_set_backlight(dev, dev_priv->backlight_duty_cycle);
 103         } else {
 104                 intel_lvds_set_backlight(dev, 0);
 105
 106                 I915_WRITE(ctl_reg, I915_READ(ctl_reg) &
 107                            ~POWER_TARGET_ON);
 108                 do {
 109                         pp_status = I915_READ(status_reg);
 110                 } while (pp_status & PP_ON);
 111         }
 112 }
 113
 114 static void intel_lvds_dpms(struct drm_encoder *encoder, int mode)
 115 {
 116         struct drm_device *dev = encoder->dev;
 117
 118         if (mode == DRM_MODE_DPMS_ON)
 119                 intel_lvds_set_power(dev, true);
 120         else
 121                 intel_lvds_set_power(dev, false);
 122
 123         /* XXX: We never power down the LVDS pairs. */
 124 }
 125
 126 static void intel_lvds_save(struct drm_connector *connector)
 127 {
 128         struct drm_device *dev = connector->dev;
 129         struct drm_i915_private *dev_priv = dev->dev_private;
 130         u32 pp_on_reg, pp_off_reg, pp_ctl_reg, pp_div_reg;
 131         u32 pwm_ctl_reg;
 132
 133         if (IS_IGDNG(dev)) {
 134                 pp_on_reg = PCH_PP_ON_DELAYS;
 135                 pp_off_reg = PCH_PP_OFF_DELAYS;
 136                 pp_ctl_reg = PCH_PP_CONTROL;
 137                 pp_div_reg = PCH_PP_DIVISOR;
 138                 pwm_ctl_reg = BLC_PWM_CPU_CTL;
 139         } else {
 140                 pp_on_reg = PP_ON_DELAYS;
 141                 pp_off_reg = PP_OFF_DELAYS;
 142                 pp_ctl_reg = PP_CONTROL;
 143                 pp_div_reg = PP_DIVISOR;
 144                 pwm_ctl_reg = BLC_PWM_CTL;
 145         }
 146
 147         dev_priv->savePP_ON = I915_READ(pp_on_reg);
 148         dev_priv->savePP_OFF = I915_READ(pp_off_reg);
 149         dev_priv->savePP_CONTROL = I915_READ(pp_ctl_reg);
 150         dev_priv->savePP_DIVISOR = I915_READ(pp_div_reg);
 151         dev_priv->saveBLC_PWM_CTL = I915_READ(pwm_ctl_reg);
 152         dev_priv->backlight_duty_cycle = (dev_priv->saveBLC_PWM_CTL &
 153                                        BACKLIGHT_DUTY_CYCLE_MASK);
 154
 155         /*
 156          * If the light is off at server startup, just make it full brightness
 157          */
 158         if (dev_priv->backlight_duty_cycle == 0)
 159                 dev_priv->backlight_duty_cycle =
 160                         intel_lvds_get_max_backlight(dev);
 161 }
 162
 163 static void intel_lvds_restore(struct drm_connector *connector)
 164 {
 165         struct drm_device *dev = connector->dev;
 166         struct drm_i915_private *dev_priv = dev->dev_private;
 167         u32 pp_on_reg, pp_off_reg, pp_ctl_reg, pp_div_reg;
 168         u32 pwm_ctl_reg;
 169
 170         if (IS_IGDNG(dev)) {
 171                 pp_on_reg = PCH_PP_ON_DELAYS;
 172                 pp_off_reg = PCH_PP_OFF_DELAYS;
 173                 pp_ctl_reg = PCH_PP_CONTROL;
 174                 pp_div_reg = PCH_PP_DIVISOR;
 175                 pwm_ctl_reg = BLC_PWM_CPU_CTL;
 176         } else {
 177                 pp_on_reg = PP_ON_DELAYS;
 178                 pp_off_reg = PP_OFF_DELAYS;
 179                 pp_ctl_reg = PP_CONTROL;
 180                 pp_div_reg = PP_DIVISOR;
 181                 pwm_ctl_reg = BLC_PWM_CTL;
 182         }
 183
 184         I915_WRITE(pwm_ctl_reg, dev_priv->saveBLC_PWM_CTL);
 185         I915_WRITE(pp_on_reg, dev_priv->savePP_ON);
 186         I915_WRITE(pp_off_reg, dev_priv->savePP_OFF);
 187         I915_WRITE(pp_div_reg, dev_priv->savePP_DIVISOR);
 188         I915_WRITE(pp_ctl_reg, dev_priv->savePP_CONTROL);
 189         if (dev_priv->savePP_CONTROL & POWER_TARGET_ON)
 190                 intel_lvds_set_power(dev, true);
 191         else
 192                 intel_lvds_set_power(dev, false);
 193 }
 194
 195 static int intel_lvds_mode_valid(struct drm_connector *connector,
 196                                  struct drm_display_mode *mode)
 197 {
 198         struct drm_device *dev = connector->dev;
 199         struct drm_i915_private *dev_priv = dev->dev_private;
 200         struct drm_display_mode *fixed_mode = dev_priv->panel_fixed_mode;
 201
 202         if (fixed_mode) {
 203                 if (mode->hdisplay > fixed_mode->hdisplay)
 204                         return MODE_PANEL;
 205                 if (mode->vdisplay > fixed_mode->vdisplay)
 206                         return MODE_PANEL;
 207         }
 208
 209         return MODE_OK;
 210 }
 211
 212 static bool intel_lvds_mode_fixup(struct drm_encoder *encoder,
 213                                   struct drm_display_mode *mode,
 214                                   struct drm_display_mode *adjusted_mode)
 215 {
 216         struct drm_device *dev = encoder->dev;
 217         struct drm_i915_private *dev_priv = dev->dev_private;
 218         struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 219         struct drm_encoder *tmp_encoder;
 220
 221         /* Should never happen!! */
 222         if (!IS_I965G(dev) && intel_crtc->pipe == 0) {
 223                 printk(KERN_ERR "Can't support LVDS on pipe A\n");
 224                 return false;
 225         }
 226
 227         /* Should never happen!! */
 228         list_for_each_entry(tmp_encoder, &dev->mode_config.encoder_list, head) {
 229                 if (tmp_encoder != encoder && tmp_encoder->crtc == encoder->crtc) {
 230                         printk(KERN_ERR "Can't enable LVDS and another "
 231                                "encoder on the same pipe\n");
 232                         return false;
 233                 }
 234         }
 235
 236         /*
 237          * If we have timings from the BIOS for the panel, put them in
 238          * to the adjusted mode.  The CRTC will be set up for this mode,
 239          * with the panel scaling set up to source from the H/VDisplay
 240          * of the original mode.
 241          */
 242         if (dev_priv->panel_fixed_mode != NULL) {
 243                 adjusted_mode->hdisplay = dev_priv->panel_fixed_mode->hdisplay;
 244                 adjusted_mode->hsync_start =
 245                         dev_priv->panel_fixed_mode->hsync_start;
 246                 adjusted_mode->hsync_end =
 247                         dev_priv->panel_fixed_mode->hsync_end;
 248                 adjusted_mode->htotal = dev_priv->panel_fixed_mode->htotal;
 249                 adjusted_mode->vdisplay = dev_priv->panel_fixed_mode->vdisplay;
 250                 adjusted_mode->vsync_start =
 251                         dev_priv->panel_fixed_mode->vsync_start;
 252                 adjusted_mode->vsync_end =
 253                         dev_priv->panel_fixed_mode->vsync_end;
 254                 adjusted_mode->vtotal = dev_priv->panel_fixed_mode->vtotal;
 255                 adjusted_mode->clock = dev_priv->panel_fixed_mode->clock;
 256                 drm_mode_set_crtcinfo(adjusted_mode, CRTC_INTERLACE_HALVE_V);
 257         }
 258
 259         /*
 260          * XXX: It would be nice to support lower refresh rates on the
 261          * panels to reduce power consumption, and perhaps match the
 262          * user's requested refresh rate.
 263          */
 264
 265         return true;
 266 }
 267
 268 static void intel_lvds_prepare(struct drm_encoder *encoder)
 269 {
 270         struct drm_device *dev = encoder->dev;
 271         struct drm_i915_private *dev_priv = dev->dev_private;
 272         u32 reg;
 273
 274         if (IS_IGDNG(dev))
 275                 reg = BLC_PWM_CPU_CTL;
 276         else
 277                 reg = BLC_PWM_CTL;
 278
 279         dev_priv->saveBLC_PWM_CTL = I915_READ(reg);
 280         dev_priv->backlight_duty_cycle = (dev_priv->saveBLC_PWM_CTL &
 281                                        BACKLIGHT_DUTY_CYCLE_MASK);
 282
 283         intel_lvds_set_power(dev, false);
 284 }
 285
 286 static void intel_lvds_commit( struct drm_encoder *encoder)
 287 {
 288         struct drm_device *dev = encoder->dev;
 289         struct drm_i915_private *dev_priv = dev->dev_private;
 290
 291         if (dev_priv->backlight_duty_cycle == 0)
 292                 dev_priv->backlight_duty_cycle =
 293                         intel_lvds_get_max_backlight(dev);
 294
 295         intel_lvds_set_power(dev, true);
 296 }
 297
 298 static void intel_lvds_mode_set(struct drm_encoder *encoder,
 299                                 struct drm_display_mode *mode,
 300                                 struct drm_display_mode *adjusted_mode)
 301 {
 302         struct drm_device *dev = encoder->dev;
 303         struct drm_i915_private *dev_priv = dev->dev_private;
 304         struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 305         u32 pfit_control;
 306
 307         /*
 308          * The LVDS pin pair will already have been turned on in the
 309          * intel_crtc_mode_set since it has a large impact on the DPLL
 310          * settings.
 311          */
 312
 313         /* No panel fitting yet, fixme */
 314         if (IS_IGDNG(dev))
 315                 return;
 316
 317         /*
 318          * Enable automatic panel scaling so that non-native modes fill the
 319          * screen.  Should be enabled before the pipe is enabled, according to
 320          * register description and PRM.
 321          */
 322         if (mode->hdisplay != adjusted_mode->hdisplay ||
 323             mode->vdisplay != adjusted_mode->vdisplay)
 324                 pfit_control = (PFIT_ENABLE | VERT_AUTO_SCALE |
 325                                 HORIZ_AUTO_SCALE | VERT_INTERP_BILINEAR |
 326                                 HORIZ_INTERP_BILINEAR);
 327         else
 328                 pfit_control = 0;
 329
 330         if (!IS_I965G(dev)) {
 331                 if (dev_priv->panel_wants_dither || dev_priv->lvds_dither)
 332                         pfit_control |= PANEL_8TO6_DITHER_ENABLE;
 333         }
 334         else
 335                 pfit_control |= intel_crtc->pipe << PFIT_PIPE_SHIFT;
 336
 337         I915_WRITE(PFIT_CONTROL, pfit_control);
 338 }
 339
 340 /**
 341  * Detect the LVDS connection.
 342  *
 343  * This always returns CONNECTOR_STATUS_CONNECTED.  This connector should only have
 344  * been set up if the LVDS was actually connected anyway.
 345  */
 346 static enum drm_connector_status intel_lvds_detect(struct drm_connector *connector)
 347 {
 348         return connector_status_connected;
 349 }
 350
 351 /**
 352  * Return the list of DDC modes if available, or the BIOS fixed mode otherwise.
 353  */
 354 static int intel_lvds_get_modes(struct drm_connector *connector)
 355 {
 356         struct drm_device *dev = connector->dev;
 357         struct intel_output *intel_output = to_intel_output(connector);
 358         struct drm_i915_private *dev_priv = dev->dev_private;
 359         int ret = 0;
 360
 361         ret = intel_ddc_get_modes(intel_output);
 362
 363         if (ret)
 364                 return ret;
 365
 366         /* Didn't get an EDID, so
 367          * Set wide sync ranges so we get all modes
 368          * handed to valid_mode for checking
 369          */
 370         connector->display_info.min_vfreq = 0;
 371         connector->display_info.max_vfreq = 200;
 372         connector->display_info.min_hfreq = 0;
 373         connector->display_info.max_hfreq = 200;
 374
 375         if (dev_priv->panel_fixed_mode != NULL) {
 376                 struct drm_display_mode *mode;
 377
 378                 mode = drm_mode_duplicate(dev, dev_priv->panel_fixed_mode);
 379                 drm_mode_probed_add(connector, mode);
 380
 381                 return 1;
 382         }
 383
 384         return 0;
 385 }
 386
 387 /**
 388  * intel_lvds_destroy - unregister and free LVDS structures
 389  * @connector: connector to free
 390  *
 391  * Unregister the DDC bus for this connector then free the driver private
 392  * structure.
 393  */
 394 static void intel_lvds_destroy(struct drm_connector *connector)
 395 {
 396         struct intel_output *intel_output = to_intel_output(connector);
 397
 398         if (intel_output->ddc_bus)
 399                 intel_i2c_destroy(intel_output->ddc_bus);
 400         drm_sysfs_connector_remove(connector);
 401         drm_connector_cleanup(connector);
 402         kfree(connector);
 403 }
 404
 405 static int intel_lvds_set_property(struct drm_connector *connector,
 406                                    struct drm_property *property,
 407                                    uint64_t value)
 408 {
 409         return 0;
 410 }
 411
 412 static const struct drm_encoder_helper_funcs intel_lvds_helper_funcs = {
 413         .dpms = intel_lvds_dpms,
 414         .mode_fixup = intel_lvds_mode_fixup,
 415         .prepare = intel_lvds_prepare,
 416         .mode_set = intel_lvds_mode_set,
 417         .commit = intel_lvds_commit,
 418 };
 419
 420 static const struct drm_connector_helper_funcs intel_lvds_connector_helper_funcs = {
 421         .get_modes = intel_lvds_get_modes,
 422         .mode_valid = intel_lvds_mode_valid,
 423         .best_encoder = intel_best_encoder,
 424 };
 425
 426 static const struct drm_connector_funcs intel_lvds_connector_funcs = {
 427         .dpms = drm_helper_connector_dpms,
 428         .save = intel_lvds_save,
 429         .restore = intel_lvds_restore,
 430         .detect = intel_lvds_detect,
 431         .fill_modes = drm_helper_probe_single_connector_modes,
 432         .set_property = intel_lvds_set_property,
 433         .destroy = intel_lvds_destroy,
 434 };
 435
 436
 437 static void intel_lvds_enc_destroy(struct drm_encoder *encoder)
 438 {
 439         drm_encoder_cleanup(encoder);
 440 }
 441
 442 static const struct drm_encoder_funcs intel_lvds_enc_funcs = {
 443         .destroy = intel_lvds_enc_destroy,
 444 };
 445
 446 static int __init intel_no_lvds_dmi_callback(const struct dmi_system_id *id)
 447 {
 448         DRM_DEBUG_KMS(I915_LVDS,
 449                       "Skipping LVDS initialization for %s\n", id->ident);
 450         return 1;
 451 }
 452
 453 /* These systems claim to have LVDS, but really don't */
 454 static const struct dmi_system_id intel_no_lvds[] = {
 455         {
 456                 .callback = intel_no_lvds_dmi_callback,
 457                 .ident = "Apple Mac Mini (Core series)",
 458                 .matches = {
 459                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 460                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
 461                 },
 462         },
 463         {
 464                 .callback = intel_no_lvds_dmi_callback,
 465                 .ident = "Apple Mac Mini (Core 2 series)",
 466                 .matches = {
 467                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
 468                         DMI_MATCH(DMI_PRODUCT_NAME, "Macmini2,1"),
 469                 },
 470         },
 471         {
 472                 .callback = intel_no_lvds_dmi_callback,
 473                 .ident = "MSI IM-945GSE-A",
 474                 .matches = {
 475                         DMI_MATCH(DMI_SYS_VENDOR, "MSI"),
 476                         DMI_MATCH(DMI_PRODUCT_NAME, "A9830IMS"),
 477                 },
 478         },
 479         {
 480                 .callback = intel_no_lvds_dmi_callback,
 481                 .ident = "Dell Studio Hybrid",
 482                 .matches = {
 483                         DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 484                         DMI_MATCH(DMI_PRODUCT_NAME, "Studio Hybrid 140g"),
 485                 },
 486         },
 487         {
 488                 .callback = intel_no_lvds_dmi_callback,
 489                 .ident = "AOpen Mini PC",
 490                 .matches = {
 491                         DMI_MATCH(DMI_SYS_VENDOR, "AOpen"),
 492                         DMI_MATCH(DMI_PRODUCT_NAME, "i965GMx-IF"),
 493                 },
 494         },
 495         {
 496                 .callback = intel_no_lvds_dmi_callback,
 497                 .ident = "Aopen i945GTt-VFA",
 498                 .matches = {
 499                         DMI_MATCH(DMI_PRODUCT_VERSION, "AO00001JW"),
 500                 },
 501         },
 502
 503         { }     /* terminating entry */
 504 };
 505
 506 /**
 507  * intel_lvds_init - setup LVDS connectors on this device
 508  * @dev: drm device
 509  *
 510  * Create the connector, register the LVDS DDC bus, and try to figure out what
 511  * modes we can display on the LVDS panel (if present).
 512  */
 513 void intel_lvds_init(struct drm_device *dev)
 514 {
 515         struct drm_i915_private *dev_priv = dev->dev_private;
 516         struct intel_output *intel_output;
 517         struct drm_connector *connector;
 518         struct drm_encoder *encoder;
 519         struct drm_display_mode *scan; /* *modes, *bios_mode; */
 520         struct drm_crtc *crtc;
 521         u32 lvds;
 522         int pipe, gpio = GPIOC;
 523
 524         /* Skip init on machines we know falsely report LVDS */
 525         if (dmi_check_system(intel_no_lvds))
 526                 return;
 527
 528         if (IS_IGDNG(dev)) {
 529                 if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
 530                         return;
 531                 gpio = PCH_GPIOC;
 532         }
 533
 534         intel_output = kzalloc(sizeof(struct intel_output), GFP_KERNEL);
 535         if (!intel_output) {
 536                 return;
 537         }
 538
 539         connector = &intel_output->base;
 540         encoder = &intel_output->enc;
 541         drm_connector_init(dev, &intel_output->base, &intel_lvds_connector_funcs,
 542                            DRM_MODE_CONNECTOR_LVDS);
 543
 544         drm_encoder_init(dev, &intel_output->enc, &intel_lvds_enc_funcs,
 545                          DRM_MODE_ENCODER_LVDS);
 546
 547         drm_mode_connector_attach_encoder(&intel_output->base, &intel_output->enc);
 548         intel_output->type = INTEL_OUTPUT_LVDS;
 549
 550         drm_encoder_helper_add(encoder, &intel_lvds_helper_funcs);
 551         drm_connector_helper_add(connector, &intel_lvds_connector_helper_funcs);
 552         connector->display_info.subpixel_order = SubPixelHorizontalRGB;
 553         connector->interlace_allowed = false;
 554         connector->doublescan_allowed = false;
 555
 556
 557         /*
 558          * LVDS discovery:
 559          * 1) check for EDID on DDC
 560          * 2) check for VBT data
 561          * 3) check to see if LVDS is already on
 562          *    if none of the above, no panel
 563          * 4) make sure lid is open
 564          *    if closed, act like it's not there for now
 565          */
 566
 567         /* Set up the DDC bus. */
 568         intel_output->ddc_bus = intel_i2c_create(dev, gpio, "LVDSDDC_C");
 569         if (!intel_output->ddc_bus) {
 570                 dev_printk(KERN_ERR, &dev->pdev->dev, "DDC bus registration "
 571                            "failed.\n");
 572                 goto failed;
 573         }
 574
 575         /*
 576          * Attempt to get the fixed panel mode from DDC.  Assume that the
 577          * preferred mode is the right one.
 578          */
 579         intel_ddc_get_modes(intel_output);
 580
 581         list_for_each_entry(scan, &connector->probed_modes, head) {
 582                 mutex_lock(&dev->mode_config.mutex);
 583                 if (scan->type & DRM_MODE_TYPE_PREFERRED) {
 584                         dev_priv->panel_fixed_mode =
 585                                 drm_mode_duplicate(dev, scan);
 586                         mutex_unlock(&dev->mode_config.mutex);
 587                         goto out;
 588                 }
 589                 mutex_unlock(&dev->mode_config.mutex);
 590         }
 591
 592         /* Failed to get EDID, what about VBT? */
 593         if (dev_priv->lfp_lvds_vbt_mode) {
 594                 mutex_lock(&dev->mode_config.mutex);
 595                 dev_priv->panel_fixed_mode =
 596                         drm_mode_duplicate(dev, dev_priv->lfp_lvds_vbt_mode);
 597                 mutex_unlock(&dev->mode_config.mutex);
 598                 if (dev_priv->panel_fixed_mode) {
 599                         dev_priv->panel_fixed_mode->type |=
 600                                 DRM_MODE_TYPE_PREFERRED;
 601                         goto out;
 602                 }
 603         }
 604
 605         /*
 606          * If we didn't get EDID, try checking if the panel is already turned
 607          * on.  If so, assume that whatever is currently programmed is the
 608          * correct mode.
 609          */
 610
 611         /* IGDNG: FIXME if still fail, not try pipe mode now */
 612         if (IS_IGDNG(dev))
 613                 goto failed;
 614
 615         lvds = I915_READ(LVDS);
 616         pipe = (lvds & LVDS_PIPEB_SELECT) ? 1 : 0;
 617         crtc = intel_get_crtc_from_pipe(dev, pipe);
 618
 619         if (crtc && (lvds & LVDS_PORT_EN)) {
 620                 dev_priv->panel_fixed_mode = intel_crtc_mode_get(dev, crtc);
 621                 if (dev_priv->panel_fixed_mode) {
 622                         dev_priv->panel_fixed_mode->type |=
 623                                 DRM_MODE_TYPE_PREFERRED;
 624                         goto out;
 625                 }
 626         }
 627
 628         /* If we still don't have a mode after all that, give up. */
 629         if (!dev_priv->panel_fixed_mode)
 630                 goto failed;
 631
 632 out:
 633         if (IS_IGDNG(dev)) {
 634                 u32 pwm;
 635                 /* make sure PWM is enabled */
 636                 pwm = I915_READ(BLC_PWM_CPU_CTL2);
 637                 pwm |= (PWM_ENABLE | PWM_PIPE_B);
 638                 I915_WRITE(BLC_PWM_CPU_CTL2, pwm);
 639
 640                 pwm = I915_READ(BLC_PWM_PCH_CTL1);
 641                 pwm |= PWM_PCH_ENABLE;
 642                 I915_WRITE(BLC_PWM_PCH_CTL1, pwm);
 643         }
 644         drm_sysfs_connector_add(connector);
 645         return;
 646
 647 failed:
 648         DRM_DEBUG_KMS(I915_LVDS, "No LVDS modes found, disabling.\n");
 649         if (intel_output->ddc_bus)
 650                 intel_i2c_destroy(intel_output->ddc_bus);
 651         drm_connector_cleanup(connector);
 652         kfree(connector);
 653 }