drivers/gpu/drm/drm_crtc_helper.c

   1 /*
   2  * Copyright (c) 2006-2008 Intel Corporation
   3  * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
   4  *
   5  * DRM core CRTC related functions
   6  *
   7  * Permission to use, copy, modify, distribute, and sell this software and its
   8  * documentation for any purpose is hereby granted without fee, provided that
   9  * the above copyright notice appear in all copies and that both that copyright
  10  * notice and this permission notice appear in supporting documentation, and
  11  * that the name of the copyright holders not be used in advertising or
  12  * publicity pertaining to distribution of the software without specific,
  13  * written prior permission.  The copyright holders make no representations
  14  * about the suitability of this software for any purpose.  It is provided "as
  15  * is" without express or implied warranty.
  16  *
  17  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  18  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  19  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  20  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  21  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  22  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  23  * OF THIS SOFTWARE.
  24  *
  25  * Authors:
  26  *      Keith Packard
  27  *      Eric Anholt <eric@anholt.net>
  28  *      Dave Airlie <airlied@linux.ie>
  29  *      Jesse Barnes <jesse.barnes@intel.com>
  30  */
  31
  32 #include <linux/export.h>
  33 #include <linux/moduleparam.h>
  34
  35 #include <drm/drmP.h>
  36 #include <drm/drm_crtc.h>
  37 #include <drm/drm_fourcc.h>
  38 #include <drm/drm_crtc_helper.h>
  39 #include <drm/drm_fb_helper.h>
  40 #include <drm/drm_edid.h>
  41
  42 MODULE_AUTHOR("David Airlie, Jesse Barnes");
  43 MODULE_DESCRIPTION("DRM KMS helper");
  44 MODULE_LICENSE("GPL and additional rights");
  45
  46 /**
  47  * drm_helper_move_panel_connectors_to_head() - move panels to the front in the
  48  *                                              connector list
  49  * @dev: drm device to operate on
  50  *
  51  * Some userspace presumes that the first connected connector is the main
  52  * display, where it's supposed to display e.g. the login screen. For
  53  * laptops, this should be the main panel. Use this function to sort all
  54  * (eDP/LVDS) panels to the front of the connector list, instead of
  55  * painstakingly trying to initialize them in the right order.
  56  */
  57 void drm_helper_move_panel_connectors_to_head(struct drm_device *dev)
  58 {
  59         struct drm_connector *connector, *tmp;
  60         struct list_head panel_list;
  61
  62         INIT_LIST_HEAD(&panel_list);
  63
  64         list_for_each_entry_safe(connector, tmp,
  65                                  &dev->mode_config.connector_list, head) {
  66                 if (connector->connector_type == DRM_MODE_CONNECTOR_LVDS ||
  67                     connector->connector_type == DRM_MODE_CONNECTOR_eDP)
  68                         list_move_tail(&connector->head, &panel_list);
  69         }
  70
  71         list_splice(&panel_list, &dev->mode_config.connector_list);
  72 }
  73 EXPORT_SYMBOL(drm_helper_move_panel_connectors_to_head);
  74
  75 static bool drm_kms_helper_poll = true;
  76 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
  77
  78 static void drm_mode_validate_flag(struct drm_connector *connector,
  79                                    int flags)
  80 {
  81         struct drm_display_mode *mode;
  82
  83         if (flags == (DRM_MODE_FLAG_DBLSCAN | DRM_MODE_FLAG_INTERLACE |
  84                       DRM_MODE_FLAG_3D_MASK))
  85                 return;
  86
  87         list_for_each_entry(mode, &connector->modes, head) {
  88                 if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
  89                                 !(flags & DRM_MODE_FLAG_INTERLACE))
  90                         mode->status = MODE_NO_INTERLACE;
  91                 if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
  92                                 !(flags & DRM_MODE_FLAG_DBLSCAN))
  93                         mode->status = MODE_NO_DBLESCAN;
  94                 if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
  95                                 !(flags & DRM_MODE_FLAG_3D_MASK))
  96                         mode->status = MODE_NO_STEREO;
  97         }
  98
  99         return;
 100 }
 101
 102 /**
 103  * drm_helper_probe_single_connector_modes - get complete set of display modes
 104  * @connector: connector to probe
 105  * @maxX: max width for modes
 106  * @maxY: max height for modes
 107  *
 108  * Based on the helper callbacks implemented by @connector try to detect all
 109  * valid modes.  Modes will first be added to the connector's probed_modes list,
 110  * then culled (based on validity and the @maxX, @maxY parameters) and put into
 111  * the normal modes list.
 112  *
 113  * Intended to be use as a generic implementation of the ->fill_modes()
 114  * @connector vfunc for drivers that use the crtc helpers for output mode
 115  * filtering and detection.
 116  *
 117  * Returns:
 118  * The number of modes found on @connector.
 119  */
 120 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 121                                             uint32_t maxX, uint32_t maxY)
 122 {
 123         struct drm_device *dev = connector->dev;
 124         struct drm_display_mode *mode;
 125         struct drm_connector_helper_funcs *connector_funcs =
 126                 connector->helper_private;
 127         int count = 0;
 128         int mode_flags = 0;
 129         bool verbose_prune = true;
 130
 131         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 132
 133         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
 134                         drm_get_connector_name(connector));
 135         /* set all modes to the unverified state */
 136         list_for_each_entry(mode, &connector->modes, head)
 137                 mode->status = MODE_UNVERIFIED;
 138
 139         if (connector->force) {
 140                 if (connector->force == DRM_FORCE_ON)
 141                         connector->status = connector_status_connected;
 142                 else
 143                         connector->status = connector_status_disconnected;
 144                 if (connector->funcs->force)
 145                         connector->funcs->force(connector);
 146         } else {
 147                 connector->status = connector->funcs->detect(connector, true);
 148         }
 149
 150         /* Re-enable polling in case the global poll config changed. */
 151         if (drm_kms_helper_poll != dev->mode_config.poll_running)
 152                 drm_kms_helper_poll_enable(dev);
 153
 154         dev->mode_config.poll_running = drm_kms_helper_poll;
 155
 156         if (connector->status == connector_status_disconnected) {
 157                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
 158                         connector->base.id, drm_get_connector_name(connector));
 159                 drm_mode_connector_update_edid_property(connector, NULL);
 160                 verbose_prune = false;
 161                 goto prune;
 162         }
 163
 164 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
 165         count = drm_load_edid_firmware(connector);
 166         if (count == 0)
 167 #endif
 168                 count = (*connector_funcs->get_modes)(connector);
 169
 170         if (count == 0 && connector->status == connector_status_connected)
 171                 count = drm_add_modes_noedid(connector, 1024, 768);
 172         if (count == 0)
 173                 goto prune;
 174
 175         drm_mode_connector_list_update(connector);
 176
 177         if (maxX && maxY)
 178                 drm_mode_validate_size(dev, &connector->modes, maxX, maxY);
 179
 180         if (connector->interlace_allowed)
 181                 mode_flags |= DRM_MODE_FLAG_INTERLACE;
 182         if (connector->doublescan_allowed)
 183                 mode_flags |= DRM_MODE_FLAG_DBLSCAN;
 184         if (connector->stereo_allowed)
 185                 mode_flags |= DRM_MODE_FLAG_3D_MASK;
 186         drm_mode_validate_flag(connector, mode_flags);
 187
 188         list_for_each_entry(mode, &connector->modes, head) {
 189                 if (mode->status == MODE_OK)
 190                         mode->status = connector_funcs->mode_valid(connector,
 191                                                                    mode);
 192         }
 193
 194 prune:
 195         drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
 196
 197         if (list_empty(&connector->modes))
 198                 return 0;
 199
 200         list_for_each_entry(mode, &connector->modes, head)
 201                 mode->vrefresh = drm_mode_vrefresh(mode);
 202
 203         drm_mode_sort(&connector->modes);
 204
 205         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
 206                         drm_get_connector_name(connector));
 207         list_for_each_entry(mode, &connector->modes, head) {
 208                 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
 209                 drm_mode_debug_printmodeline(mode);
 210         }
 211
 212         return count;
 213 }
 214 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
 215
 216 /**
 217  * drm_helper_encoder_in_use - check if a given encoder is in use
 218  * @encoder: encoder to check
 219  *
 220  * Checks whether @encoder is with the current mode setting output configuration
 221  * in use by any connector. This doesn't mean that it is actually enabled since
 222  * the DPMS state is tracked separately.
 223  *
 224  * Returns:
 225  * True if @encoder is used, false otherwise.
 226  */
 227 bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
 228 {
 229         struct drm_connector *connector;
 230         struct drm_device *dev = encoder->dev;
 231
 232         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 233         list_for_each_entry(connector, &dev->mode_config.connector_list, head)
 234                 if (connector->encoder == encoder)
 235                         return true;
 236         return false;
 237 }
 238 EXPORT_SYMBOL(drm_helper_encoder_in_use);
 239
 240 /**
 241  * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 242  * @crtc: CRTC to check
 243  *
 244  * Checks whether @crtc is with the current mode setting output configuration
 245  * in use by any connector. This doesn't mean that it is actually enabled since
 246  * the DPMS state is tracked separately.
 247  *
 248  * Returns:
 249  * True if @crtc is used, false otherwise.
 250  */
 251 bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
 252 {
 253         struct drm_encoder *encoder;
 254         struct drm_device *dev = crtc->dev;
 255
 256         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 257         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head)
 258                 if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
 259                         return true;
 260         return false;
 261 }
 262 EXPORT_SYMBOL(drm_helper_crtc_in_use);
 263
 264 static void
 265 drm_encoder_disable(struct drm_encoder *encoder)
 266 {
 267         struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
 268
 269         if (encoder->bridge)
 270                 encoder->bridge->funcs->disable(encoder->bridge);
 271
 272         if (encoder_funcs->disable)
 273                 (*encoder_funcs->disable)(encoder);
 274         else
 275                 (*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
 276
 277         if (encoder->bridge)
 278                 encoder->bridge->funcs->post_disable(encoder->bridge);
 279 }
 280
 281 static void __drm_helper_disable_unused_functions(struct drm_device *dev)
 282 {
 283         struct drm_encoder *encoder;
 284         struct drm_connector *connector;
 285         struct drm_crtc *crtc;
 286
 287         drm_warn_on_modeset_not_all_locked(dev);
 288
 289         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 290                 if (!connector->encoder)
 291                         continue;
 292                 if (connector->status == connector_status_disconnected)
 293                         connector->encoder = NULL;
 294         }
 295
 296         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 297                 if (!drm_helper_encoder_in_use(encoder)) {
 298                         drm_encoder_disable(encoder);
 299                         /* disconnector encoder from any connector */
 300                         encoder->crtc = NULL;
 301                 }
 302         }
 303
 304         list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 305                 struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 306                 crtc->enabled = drm_helper_crtc_in_use(crtc);
 307                 if (!crtc->enabled) {
 308                         if (crtc_funcs->disable)
 309                                 (*crtc_funcs->disable)(crtc);
 310                         else
 311                                 (*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
 312                         crtc->fb = NULL;
 313                 }
 314         }
 315 }
 316
 317 /**
 318  * drm_helper_disable_unused_functions - disable unused objects
 319  * @dev: DRM device
 320  *
 321  * This function walks through the entire mode setting configuration of @dev. It
 322  * will remove any crtc links of unused encoders and encoder links of
 323  * disconnected connectors. Then it will disable all unused encoders and crtcs
 324  * either by calling their disable callback if available or by calling their
 325  * dpms callback with DRM_MODE_DPMS_OFF.
 326  */
 327 void drm_helper_disable_unused_functions(struct drm_device *dev)
 328 {
 329         drm_modeset_lock_all(dev);
 330         __drm_helper_disable_unused_functions(dev);
 331         drm_modeset_unlock_all(dev);
 332 }
 333 EXPORT_SYMBOL(drm_helper_disable_unused_functions);
 334
 335 /*
 336  * Check the CRTC we're going to map each output to vs. its current
 337  * CRTC.  If they don't match, we have to disable the output and the CRTC
 338  * since the driver will have to re-route things.
 339  */
 340 static void
 341 drm_crtc_prepare_encoders(struct drm_device *dev)
 342 {
 343         struct drm_encoder_helper_funcs *encoder_funcs;
 344         struct drm_encoder *encoder;
 345
 346         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 347                 encoder_funcs = encoder->helper_private;
 348                 /* Disable unused encoders */
 349                 if (encoder->crtc == NULL)
 350                         drm_encoder_disable(encoder);
 351                 /* Disable encoders whose CRTC is about to change */
 352                 if (encoder_funcs->get_crtc &&
 353                     encoder->crtc != (*encoder_funcs->get_crtc)(encoder))
 354                         drm_encoder_disable(encoder);
 355         }
 356 }
 357
 358 /**
 359  * drm_crtc_helper_set_mode - internal helper to set a mode
 360  * @crtc: CRTC to program
 361  * @mode: mode to use
 362  * @x: horizontal offset into the surface
 363  * @y: vertical offset into the surface
 364  * @old_fb: old framebuffer, for cleanup
 365  *
 366  * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
 367  * to fixup or reject the mode prior to trying to set it. This is an internal
 368  * helper that drivers could e.g. use to update properties that require the
 369  * entire output pipe to be disabled and re-enabled in a new configuration. For
 370  * example for changing whether audio is enabled on a hdmi link or for changing
 371  * panel fitter or dither attributes. It is also called by the
 372  * drm_crtc_helper_set_config() helper function to drive the mode setting
 373  * sequence.
 374  *
 375  * Returns:
 376  * True if the mode was set successfully, false otherwise.
 377  */
 378 bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
 379                               struct drm_display_mode *mode,
 380                               int x, int y,
 381                               struct drm_framebuffer *old_fb)
 382 {
 383         struct drm_device *dev = crtc->dev;
 384         struct drm_display_mode *adjusted_mode, saved_mode;
 385         struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 386         struct drm_encoder_helper_funcs *encoder_funcs;
 387         int saved_x, saved_y;
 388         bool saved_enabled;
 389         struct drm_encoder *encoder;
 390         bool ret = true;
 391
 392         drm_warn_on_modeset_not_all_locked(dev);
 393
 394         saved_enabled = crtc->enabled;
 395         crtc->enabled = drm_helper_crtc_in_use(crtc);
 396         if (!crtc->enabled)
 397                 return true;
 398
 399         adjusted_mode = drm_mode_duplicate(dev, mode);
 400         if (!adjusted_mode) {
 401                 crtc->enabled = saved_enabled;
 402                 return false;
 403         }
 404
 405         saved_mode = crtc->mode;
 406         saved_x = crtc->x;
 407         saved_y = crtc->y;
 408
 409         /* Update crtc values up front so the driver can rely on them for mode
 410          * setting.
 411          */
 412         crtc->mode = *mode;
 413         crtc->x = x;
 414         crtc->y = y;
 415
 416         /* Pass our mode to the connectors and the CRTC to give them a chance to
 417          * adjust it according to limitations or connector properties, and also
 418          * a chance to reject the mode entirely.
 419          */
 420         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 421
 422                 if (encoder->crtc != crtc)
 423                         continue;
 424
 425                 if (encoder->bridge && encoder->bridge->funcs->mode_fixup) {
 426                         ret = encoder->bridge->funcs->mode_fixup(
 427                                         encoder->bridge, mode, adjusted_mode);
 428                         if (!ret) {
 429                                 DRM_DEBUG_KMS("Bridge fixup failed\n");
 430                                 goto done;
 431                         }
 432                 }
 433
 434                 encoder_funcs = encoder->helper_private;
 435                 if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
 436                                                       adjusted_mode))) {
 437                         DRM_DEBUG_KMS("Encoder fixup failed\n");
 438                         goto done;
 439                 }
 440         }
 441
 442         if (!(ret = crtc_funcs->mode_fixup(crtc, mode, adjusted_mode))) {
 443                 DRM_DEBUG_KMS("CRTC fixup failed\n");
 444                 goto done;
 445         }
 446         DRM_DEBUG_KMS("[CRTC:%d]\n", crtc->base.id);
 447
 448         /* Prepare the encoders and CRTCs before setting the mode. */
 449         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 450
 451                 if (encoder->crtc != crtc)
 452                         continue;
 453
 454                 if (encoder->bridge)
 455                         encoder->bridge->funcs->disable(encoder->bridge);
 456
 457                 encoder_funcs = encoder->helper_private;
 458                 /* Disable the encoders as the first thing we do. */
 459                 encoder_funcs->prepare(encoder);
 460
 461                 if (encoder->bridge)
 462                         encoder->bridge->funcs->post_disable(encoder->bridge);
 463         }
 464
 465         drm_crtc_prepare_encoders(dev);
 466
 467         crtc_funcs->prepare(crtc);
 468
 469         /* Set up the DPLL and any encoders state that needs to adjust or depend
 470          * on the DPLL.
 471          */
 472         ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
 473         if (!ret)
 474             goto done;
 475
 476         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 477
 478                 if (encoder->crtc != crtc)
 479                         continue;
 480
 481                 DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%d:%s]\n",
 482                         encoder->base.id, drm_get_encoder_name(encoder),
 483                         mode->base.id, mode->name);
 484                 encoder_funcs = encoder->helper_private;
 485                 encoder_funcs->mode_set(encoder, mode, adjusted_mode);
 486
 487                 if (encoder->bridge && encoder->bridge->funcs->mode_set)
 488                         encoder->bridge->funcs->mode_set(encoder->bridge, mode,
 489                                         adjusted_mode);
 490         }
 491
 492         /* Now enable the clocks, plane, pipe, and connectors that we set up. */
 493         crtc_funcs->commit(crtc);
 494
 495         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 496
 497                 if (encoder->crtc != crtc)
 498                         continue;
 499
 500                 if (encoder->bridge)
 501                         encoder->bridge->funcs->pre_enable(encoder->bridge);
 502
 503                 encoder_funcs = encoder->helper_private;
 504                 encoder_funcs->commit(encoder);
 505
 506                 if (encoder->bridge)
 507                         encoder->bridge->funcs->enable(encoder->bridge);
 508         }
 509
 510         /* Store real post-adjustment hardware mode. */
 511         crtc->hwmode = *adjusted_mode;
 512
 513         /* Calculate and store various constants which
 514          * are later needed by vblank and swap-completion
 515          * timestamping. They are derived from true hwmode.
 516          */
 517         drm_calc_timestamping_constants(crtc, &crtc->hwmode);
 518
 519         /* FIXME: add subpixel order */
 520 done:
 521         drm_mode_destroy(dev, adjusted_mode);
 522         if (!ret) {
 523                 crtc->enabled = saved_enabled;
 524                 crtc->mode = saved_mode;
 525                 crtc->x = saved_x;
 526                 crtc->y = saved_y;
 527         }
 528
 529         return ret;
 530 }
 531 EXPORT_SYMBOL(drm_crtc_helper_set_mode);
 532
 533
 534 static int
 535 drm_crtc_helper_disable(struct drm_crtc *crtc)
 536 {
 537         struct drm_device *dev = crtc->dev;
 538         struct drm_connector *connector;
 539         struct drm_encoder *encoder;
 540
 541         /* Decouple all encoders and their attached connectors from this crtc */
 542         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 543                 if (encoder->crtc != crtc)
 544                         continue;
 545
 546                 list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 547                         if (connector->encoder != encoder)
 548                                 continue;
 549
 550                         connector->encoder = NULL;
 551
 552                         /*
 553                          * drm_helper_disable_unused_functions() ought to be
 554                          * doing this, but since we've decoupled the encoder
 555                          * from the connector above, the required connection
 556                          * between them is henceforth no longer available.
 557                          */
 558                         connector->dpms = DRM_MODE_DPMS_OFF;
 559                 }
 560         }
 561
 562         __drm_helper_disable_unused_functions(dev);
 563         return 0;
 564 }
 565
 566 /**
 567  * drm_crtc_helper_set_config - set a new config from userspace
 568  * @set: mode set configuration
 569  *
 570  * Setup a new configuration, provided by the upper layers (either an ioctl call
 571  * from userspace or internally e.g. from the fbdev suppport code) in @set, and
 572  * enable it. This is the main helper functions for drivers that implement
 573  * kernel mode setting with the crtc helper functions and the assorted
 574  * ->prepare(), ->modeset() and ->commit() helper callbacks.
 575  *
 576  * Returns:
 577  * Returns 0 on success, negative errno numbers on failure.
 578  */
 579 int drm_crtc_helper_set_config(struct drm_mode_set *set)
 580 {
 581         struct drm_device *dev;
 582         struct drm_crtc *new_crtc;
 583         struct drm_encoder *save_encoders, *new_encoder, *encoder;
 584         bool mode_changed = false; /* if true do a full mode set */
 585         bool fb_changed = false; /* if true and !mode_changed just do a flip */
 586         struct drm_connector *save_connectors, *connector;
 587         int count = 0, ro, fail = 0;
 588         struct drm_crtc_helper_funcs *crtc_funcs;
 589         struct drm_mode_set save_set;
 590         int ret;
 591         int i;
 592
 593         DRM_DEBUG_KMS("\n");
 594
 595         BUG_ON(!set);
 596         BUG_ON(!set->crtc);
 597         BUG_ON(!set->crtc->helper_private);
 598
 599         /* Enforce sane interface api - has been abused by the fb helper. */
 600         BUG_ON(!set->mode && set->fb);
 601         BUG_ON(set->fb && set->num_connectors == 0);
 602
 603         crtc_funcs = set->crtc->helper_private;
 604
 605         if (!set->mode)
 606                 set->fb = NULL;
 607
 608         if (set->fb) {
 609                 DRM_DEBUG_KMS("[CRTC:%d] [FB:%d] #connectors=%d (x y) (%i %i)\n",
 610                                 set->crtc->base.id, set->fb->base.id,
 611                                 (int)set->num_connectors, set->x, set->y);
 612         } else {
 613                 DRM_DEBUG_KMS("[CRTC:%d] [NOFB]\n", set->crtc->base.id);
 614                 return drm_crtc_helper_disable(set->crtc);
 615         }
 616
 617         dev = set->crtc->dev;
 618
 619         drm_warn_on_modeset_not_all_locked(dev);
 620
 621         /*
 622          * Allocate space for the backup of all (non-pointer) encoder and
 623          * connector data.
 624          */
 625         save_encoders = kzalloc(dev->mode_config.num_encoder *
 626                                 sizeof(struct drm_encoder), GFP_KERNEL);
 627         if (!save_encoders)
 628                 return -ENOMEM;
 629
 630         save_connectors = kzalloc(dev->mode_config.num_connector *
 631                                 sizeof(struct drm_connector), GFP_KERNEL);
 632         if (!save_connectors) {
 633                 kfree(save_encoders);
 634                 return -ENOMEM;
 635         }
 636
 637         /*
 638          * Copy data. Note that driver private data is not affected.
 639          * Should anything bad happen only the expected state is
 640          * restored, not the drivers personal bookkeeping.
 641          */
 642         count = 0;
 643         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 644                 save_encoders[count++] = *encoder;
 645         }
 646
 647         count = 0;
 648         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 649                 save_connectors[count++] = *connector;
 650         }
 651
 652         save_set.crtc = set->crtc;
 653         save_set.mode = &set->crtc->mode;
 654         save_set.x = set->crtc->x;
 655         save_set.y = set->crtc->y;
 656         save_set.fb = set->crtc->fb;
 657
 658         /* We should be able to check here if the fb has the same properties
 659          * and then just flip_or_move it */
 660         if (set->crtc->fb != set->fb) {
 661                 /* If we have no fb then treat it as a full mode set */
 662                 if (set->crtc->fb == NULL) {
 663                         DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
 664                         mode_changed = true;
 665                 } else if (set->fb == NULL) {
 666                         mode_changed = true;
 667                 } else if (set->fb->pixel_format !=
 668                            set->crtc->fb->pixel_format) {
 669                         mode_changed = true;
 670                 } else
 671                         fb_changed = true;
 672         }
 673
 674         if (set->x != set->crtc->x || set->y != set->crtc->y)
 675                 fb_changed = true;
 676
 677         if (set->mode && !drm_mode_equal(set->mode, &set->crtc->mode)) {
 678                 DRM_DEBUG_KMS("modes are different, full mode set\n");
 679                 drm_mode_debug_printmodeline(&set->crtc->mode);
 680                 drm_mode_debug_printmodeline(set->mode);
 681                 mode_changed = true;
 682         }
 683
 684         /* a) traverse passed in connector list and get encoders for them */
 685         count = 0;
 686         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 687                 struct drm_connector_helper_funcs *connector_funcs =
 688                         connector->helper_private;
 689                 new_encoder = connector->encoder;
 690                 for (ro = 0; ro < set->num_connectors; ro++) {
 691                         if (set->connectors[ro] == connector) {
 692                                 new_encoder = connector_funcs->best_encoder(connector);
 693                                 /* if we can't get an encoder for a connector
 694                                    we are setting now - then fail */
 695                                 if (new_encoder == NULL)
 696                                         /* don't break so fail path works correct */
 697                                         fail = 1;
 698                                 break;
 699
 700                                 if (connector->dpms != DRM_MODE_DPMS_ON) {
 701                                         DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
 702                                         mode_changed = true;
 703                                 }
 704                         }
 705                 }
 706
 707                 if (new_encoder != connector->encoder) {
 708                         DRM_DEBUG_KMS("encoder changed, full mode switch\n");
 709                         mode_changed = true;
 710                         /* If the encoder is reused for another connector, then
 711                          * the appropriate crtc will be set later.
 712                          */
 713                         if (connector->encoder)
 714                                 connector->encoder->crtc = NULL;
 715                         connector->encoder = new_encoder;
 716                 }
 717         }
 718
 719         if (fail) {
 720                 ret = -EINVAL;
 721                 goto fail;
 722         }
 723
 724         count = 0;
 725         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 726                 if (!connector->encoder)
 727                         continue;
 728
 729                 if (connector->encoder->crtc == set->crtc)
 730                         new_crtc = NULL;
 731                 else
 732                         new_crtc = connector->encoder->crtc;
 733
 734                 for (ro = 0; ro < set->num_connectors; ro++) {
 735                         if (set->connectors[ro] == connector)
 736                                 new_crtc = set->crtc;
 737                 }
 738
 739                 /* Make sure the new CRTC will work with the encoder */
 740                 if (new_crtc &&
 741                     !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
 742                         ret = -EINVAL;
 743                         goto fail;
 744                 }
 745                 if (new_crtc != connector->encoder->crtc) {
 746                         DRM_DEBUG_KMS("crtc changed, full mode switch\n");
 747                         mode_changed = true;
 748                         connector->encoder->crtc = new_crtc;
 749                 }
 750                 if (new_crtc) {
 751                         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d]\n",
 752                                 connector->base.id, drm_get_connector_name(connector),
 753                                 new_crtc->base.id);
 754                 } else {
 755                         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
 756                                 connector->base.id, drm_get_connector_name(connector));
 757                 }
 758         }
 759
 760         /* mode_set_base is not a required function */
 761         if (fb_changed && !crtc_funcs->mode_set_base)
 762                 mode_changed = true;
 763
 764         if (mode_changed) {
 765                 if (drm_helper_crtc_in_use(set->crtc)) {
 766                         DRM_DEBUG_KMS("attempting to set mode from"
 767                                         " userspace\n");
 768                         drm_mode_debug_printmodeline(set->mode);
 769                         set->crtc->fb = set->fb;
 770                         if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
 771                                                       set->x, set->y,
 772                                                       save_set.fb)) {
 773                                 DRM_ERROR("failed to set mode on [CRTC:%d]\n",
 774                                           set->crtc->base.id);
 775                                 set->crtc->fb = save_set.fb;
 776                                 ret = -EINVAL;
 777                                 goto fail;
 778                         }
 779                         DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
 780                         for (i = 0; i < set->num_connectors; i++) {
 781                                 DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
 782                                               drm_get_connector_name(set->connectors[i]));
 783                                 set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
 784                         }
 785                 }
 786                 __drm_helper_disable_unused_functions(dev);
 787         } else if (fb_changed) {
 788                 set->crtc->x = set->x;
 789                 set->crtc->y = set->y;
 790                 set->crtc->fb = set->fb;
 791                 ret = crtc_funcs->mode_set_base(set->crtc,
 792                                                 set->x, set->y, save_set.fb);
 793                 if (ret != 0) {
 794                         set->crtc->x = save_set.x;
 795                         set->crtc->y = save_set.y;
 796                         set->crtc->fb = save_set.fb;
 797                         goto fail;
 798                 }
 799         }
 800
 801         kfree(save_connectors);
 802         kfree(save_encoders);
 803         return 0;
 804
 805 fail:
 806         /* Restore all previous data. */
 807         count = 0;
 808         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
 809                 *encoder = save_encoders[count++];
 810         }
 811
 812         count = 0;
 813         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 814                 *connector = save_connectors[count++];
 815         }
 816
 817         /* Try to restore the config */
 818         if (mode_changed &&
 819             !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
 820                                       save_set.y, save_set.fb))
 821                 DRM_ERROR("failed to restore config after modeset failure\n");
 822
 823         kfree(save_connectors);
 824         kfree(save_encoders);
 825         return ret;
 826 }
 827 EXPORT_SYMBOL(drm_crtc_helper_set_config);
 828
 829 static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
 830 {
 831         int dpms = DRM_MODE_DPMS_OFF;
 832         struct drm_connector *connector;
 833         struct drm_device *dev = encoder->dev;
 834
 835         list_for_each_entry(connector, &dev->mode_config.connector_list, head)
 836                 if (connector->encoder == encoder)
 837                         if (connector->dpms < dpms)
 838                                 dpms = connector->dpms;
 839         return dpms;
 840 }
 841
 842 /* Helper which handles bridge ordering around encoder dpms */
 843 static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
 844 {
 845         struct drm_bridge *bridge = encoder->bridge;
 846         struct drm_encoder_helper_funcs *encoder_funcs;
 847
 848         if (bridge) {
 849                 if (mode == DRM_MODE_DPMS_ON)
 850                         bridge->funcs->pre_enable(bridge);
 851                 else
 852                         bridge->funcs->disable(bridge);
 853         }
 854
 855         encoder_funcs = encoder->helper_private;
 856         if (encoder_funcs->dpms)
 857                 encoder_funcs->dpms(encoder, mode);
 858
 859         if (bridge) {
 860                 if (mode == DRM_MODE_DPMS_ON)
 861                         bridge->funcs->enable(bridge);
 862                 else
 863                         bridge->funcs->post_disable(bridge);
 864         }
 865 }
 866
 867 static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
 868 {
 869         int dpms = DRM_MODE_DPMS_OFF;
 870         struct drm_connector *connector;
 871         struct drm_device *dev = crtc->dev;
 872
 873         list_for_each_entry(connector, &dev->mode_config.connector_list, head)
 874                 if (connector->encoder && connector->encoder->crtc == crtc)
 875                         if (connector->dpms < dpms)
 876                                 dpms = connector->dpms;
 877         return dpms;
 878 }
 879
 880 /**
 881  * drm_helper_connector_dpms() - connector dpms helper implementation
 882  * @connector: affected connector
 883  * @mode: DPMS mode
 884  *
 885  * This is the main helper function provided by the crtc helper framework for
 886  * implementing the DPMS connector attribute. It computes the new desired DPMS
 887  * state for all encoders and crtcs in the output mesh and calls the ->dpms()
 888  * callback provided by the driver appropriately.
 889  */
 890 void drm_helper_connector_dpms(struct drm_connector *connector, int mode)
 891 {
 892         struct drm_encoder *encoder = connector->encoder;
 893         struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
 894         int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
 895
 896         if (mode == connector->dpms)
 897                 return;
 898
 899         old_dpms = connector->dpms;
 900         connector->dpms = mode;
 901
 902         if (encoder)
 903                 encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
 904
 905         /* from off to on, do crtc then encoder */
 906         if (mode < old_dpms) {
 907                 if (crtc) {
 908                         struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 909                         if (crtc_funcs->dpms)
 910                                 (*crtc_funcs->dpms) (crtc,
 911                                                      drm_helper_choose_crtc_dpms(crtc));
 912                 }
 913                 if (encoder)
 914                         drm_helper_encoder_dpms(encoder, encoder_dpms);
 915         }
 916
 917         /* from on to off, do encoder then crtc */
 918         if (mode > old_dpms) {
 919                 if (encoder)
 920                         drm_helper_encoder_dpms(encoder, encoder_dpms);
 921                 if (crtc) {
 922                         struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 923                         if (crtc_funcs->dpms)
 924                                 (*crtc_funcs->dpms) (crtc,
 925                                                      drm_helper_choose_crtc_dpms(crtc));
 926                 }
 927         }
 928
 929         return;
 930 }
 931 EXPORT_SYMBOL(drm_helper_connector_dpms);
 932
 933 /**
 934  * drm_helper_mode_fill_fb_struct - fill out framebuffer metadata
 935  * @fb: drm_framebuffer object to fill out
 936  * @mode_cmd: metadata from the userspace fb creation request
 937  *
 938  * This helper can be used in a drivers fb_create callback to pre-fill the fb's
 939  * metadata fields.
 940  */
 941 void drm_helper_mode_fill_fb_struct(struct drm_framebuffer *fb,
 942                                     struct drm_mode_fb_cmd2 *mode_cmd)
 943 {
 944         int i;
 945
 946         fb->width = mode_cmd->width;
 947         fb->height = mode_cmd->height;
 948         for (i = 0; i < 4; i++) {
 949                 fb->pitches[i] = mode_cmd->pitches[i];
 950                 fb->offsets[i] = mode_cmd->offsets[i];
 951         }
 952         drm_fb_get_bpp_depth(mode_cmd->pixel_format, &fb->depth,
 953                                     &fb->bits_per_pixel);
 954         fb->pixel_format = mode_cmd->pixel_format;
 955 }
 956 EXPORT_SYMBOL(drm_helper_mode_fill_fb_struct);
 957
 958 /**
 959  * drm_helper_resume_force_mode - force-restore mode setting configuration
 960  * @dev: drm_device which should be restored
 961  *
 962  * Drivers which use the mode setting helpers can use this function to
 963  * force-restore the mode setting configuration e.g. on resume or when something
 964  * else might have trampled over the hw state (like some overzealous old BIOSen
 965  * tended to do).
 966  *
 967  * This helper doesn't provide a error return value since restoring the old
 968  * config should never fail due to resource allocation issues since the driver
 969  * has successfully set the restored configuration already. Hence this should
 970  * boil down to the equivalent of a few dpms on calls, which also don't provide
 971  * an error code.
 972  *
 973  * Drivers where simply restoring an old configuration again might fail (e.g.
 974  * due to slight differences in allocating shared resources when the
 975  * configuration is restored in a different order than when userspace set it up)
 976  * need to use their own restore logic.
 977  */
 978 void drm_helper_resume_force_mode(struct drm_device *dev)
 979 {
 980         struct drm_crtc *crtc;
 981         struct drm_encoder *encoder;
 982         struct drm_crtc_helper_funcs *crtc_funcs;
 983         int encoder_dpms;
 984         bool ret;
 985
 986         drm_modeset_lock_all(dev);
 987         list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 988
 989                 if (!crtc->enabled)
 990                         continue;
 991
 992                 ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
 993                                                crtc->x, crtc->y, crtc->fb);
 994
 995                 /* Restoring the old config should never fail! */
 996                 if (ret == false)
 997                         DRM_ERROR("failed to set mode on crtc %p\n", crtc);
 998
 999                 /* Turn off outputs that were already powered off */
1000                 if (drm_helper_choose_crtc_dpms(crtc)) {
1001                         list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
1002
1003                                 if(encoder->crtc != crtc)
1004                                         continue;
1005
1006                                 encoder_dpms = drm_helper_choose_encoder_dpms(
1007                                                         encoder);
1008
1009                                 drm_helper_encoder_dpms(encoder, encoder_dpms);
1010                         }
1011
1012                         crtc_funcs = crtc->helper_private;
1013                         if (crtc_funcs->dpms)
1014                                 (*crtc_funcs->dpms) (crtc,
1015                                                      drm_helper_choose_crtc_dpms(crtc));
1016                 }
1017         }
1018
1019         /* disable the unused connectors while restoring the modesetting */
1020         __drm_helper_disable_unused_functions(dev);
1021         drm_modeset_unlock_all(dev);
1022 }
1023 EXPORT_SYMBOL(drm_helper_resume_force_mode);
1024
1025 /**
1026  * drm_kms_helper_hotplug_event - fire off KMS hotplug events
1027  * @dev: drm_device whose connector state changed
1028  *
1029  * This function fires off the uevent for userspace and also calls the
1030  * output_poll_changed function, which is most commonly used to inform the fbdev
1031  * emulation code and allow it to update the fbcon output configuration.
1032  *
1033  * Drivers should call this from their hotplug handling code when a change is
1034  * detected. Note that this function does not do any output detection of its
1035  * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
1036  * driver already.
1037  *
1038  * This function must be called from process context with no mode
1039  * setting locks held.
1040  */
1041 void drm_kms_helper_hotplug_event(struct drm_device *dev)
1042 {
1043         /* send a uevent + call fbdev */
1044         drm_sysfs_hotplug_event(dev);
1045         if (dev->mode_config.funcs->output_poll_changed)
1046                 dev->mode_config.funcs->output_poll_changed(dev);
1047 }
1048 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
1049
1050 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
1051 static void output_poll_execute(struct work_struct *work)
1052 {
1053         struct delayed_work *delayed_work = to_delayed_work(work);
1054         struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
1055         struct drm_connector *connector;
1056         enum drm_connector_status old_status;
1057         bool repoll = false, changed = false;
1058
1059         if (!drm_kms_helper_poll)
1060                 return;
1061
1062         mutex_lock(&dev->mode_config.mutex);
1063         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
1064
1065                 /* Ignore forced connectors. */
1066                 if (connector->force)
1067                         continue;
1068
1069                 /* Ignore HPD capable connectors and connectors where we don't
1070                  * want any hotplug detection at all for polling. */
1071                 if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
1072                         continue;
1073
1074                 repoll = true;
1075
1076                 old_status = connector->status;
1077                 /* if we are connected and don't want to poll for disconnect
1078                    skip it */
1079                 if (old_status == connector_status_connected &&
1080                     !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
1081                         continue;
1082
1083                 connector->status = connector->funcs->detect(connector, false);
1084                 if (old_status != connector->status) {
1085                         const char *old, *new;
1086
1087                         old = drm_get_connector_status_name(old_status);
1088                         new = drm_get_connector_status_name(connector->status);
1089
1090                         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
1091                                       "status updated from %s to %s\n",
1092                                       connector->base.id,
1093                                       drm_get_connector_name(connector),
1094                                       old, new);
1095
1096                         changed = true;
1097                 }
1098         }
1099
1100         mutex_unlock(&dev->mode_config.mutex);
1101
1102         if (changed)
1103                 drm_kms_helper_hotplug_event(dev);
1104
1105         if (repoll)
1106                 schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
1107 }
1108
1109 /**
1110  * drm_kms_helper_poll_disable - disable output polling
1111  * @dev: drm_device
1112  *
1113  * This function disables the output polling work.
1114  *
1115  * Drivers can call this helper from their device suspend implementation. It is
1116  * not an error to call this even when output polling isn't enabled or arlready
1117  * disabled.
1118  */
1119 void drm_kms_helper_poll_disable(struct drm_device *dev)
1120 {
1121         if (!dev->mode_config.poll_enabled)
1122                 return;
1123         cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
1124 }
1125 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
1126
1127 /**
1128  * drm_kms_helper_poll_enable - re-enable output polling.
1129  * @dev: drm_device
1130  *
1131  * This function re-enables the output polling work.
1132  *
1133  * Drivers can call this helper from their device resume implementation. It is
1134  * an error to call this when the output polling support has not yet been set
1135  * up.
1136  */
1137 void drm_kms_helper_poll_enable(struct drm_device *dev)
1138 {
1139         bool poll = false;
1140         struct drm_connector *connector;
1141
1142         if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
1143                 return;
1144
1145         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
1146                 if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
1147                                          DRM_CONNECTOR_POLL_DISCONNECT))
1148                         poll = true;
1149         }
1150
1151         if (poll)
1152                 schedule_delayed_work(&dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD);
1153 }
1154 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
1155
1156 /**
1157  * drm_kms_helper_poll_init - initialize and enable output polling
1158  * @dev: drm_device
1159  *
1160  * This function intializes and then also enables output polling support for
1161  * @dev. Drivers which do not have reliable hotplug support in hardware can use
1162  * this helper infrastructure to regularly poll such connectors for changes in
1163  * their connection state.
1164  *
1165  * Drivers can control which connectors are polled by setting the
1166  * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
1167  * connectors where probing live outputs can result in visual distortion drivers
1168  * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
1169  * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
1170  * completely ignored by the polling logic.
1171  *
1172  * Note that a connector can be both polled and probed from the hotplug handler,
1173  * in case the hotplug interrupt is known to be unreliable.
1174  */
1175 void drm_kms_helper_poll_init(struct drm_device *dev)
1176 {
1177         INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
1178         dev->mode_config.poll_enabled = true;
1179
1180         drm_kms_helper_poll_enable(dev);
1181 }
1182 EXPORT_SYMBOL(drm_kms_helper_poll_init);
1183
1184 /**
1185  * drm_kms_helper_poll_fini - disable output polling and clean it up
1186  * @dev: drm_device
1187  */
1188 void drm_kms_helper_poll_fini(struct drm_device *dev)
1189 {
1190         drm_kms_helper_poll_disable(dev);
1191 }
1192 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
1193
1194 /**
1195  * drm_helper_hpd_irq_event - hotplug processing
1196  * @dev: drm_device
1197  *
1198  * Drivers can use this helper function to run a detect cycle on all connectors
1199  * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
1200  * other connectors are ignored, which is useful to avoid reprobing fixed
1201  * panels.
1202  *
1203  * This helper function is useful for drivers which can't or don't track hotplug
1204  * interrupts for each connector.
1205  *
1206  * Drivers which support hotplug interrupts for each connector individually and
1207  * which have a more fine-grained detect logic should bypass this code and
1208  * directly call drm_kms_helper_hotplug_event() in case the connector state
1209  * changed.
1210  *
1211  * This function must be called from process context with no mode
1212  * setting locks held.
1213  *
1214  * Note that a connector can be both polled and probed from the hotplug handler,
1215  * in case the hotplug interrupt is known to be unreliable.
1216  */
1217 bool drm_helper_hpd_irq_event(struct drm_device *dev)
1218 {
1219         struct drm_connector *connector;
1220         enum drm_connector_status old_status;
1221         bool changed = false;
1222
1223         if (!dev->mode_config.poll_enabled)
1224                 return false;
1225
1226         mutex_lock(&dev->mode_config.mutex);
1227         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
1228
1229                 /* Only handle HPD capable connectors. */
1230                 if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
1231                         continue;
1232
1233                 old_status = connector->status;
1234
1235                 connector->status = connector->funcs->detect(connector, false);
1236                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
1237                               connector->base.id,
1238                               drm_get_connector_name(connector),
1239                               drm_get_connector_status_name(old_status),
1240                               drm_get_connector_status_name(connector->status));
1241                 if (old_status != connector->status)
1242                         changed = true;
1243         }
1244
1245         mutex_unlock(&dev->mode_config.mutex);
1246
1247         if (changed)
1248                 drm_kms_helper_hotplug_event(dev);
1249
1250         return changed;
1251 }
1252 EXPORT_SYMBOL(drm_helper_hpd_irq_event);