drivers/gpu/drm/drm_probe_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 /**
  43  * DOC: output probing helper overview
  44  *
  45  * This library provides some helper code for output probing. It provides an
  46  * implementation of the core connector->fill_modes interface with
  47  * drm_helper_probe_single_connector_modes.
  48  *
  49  * It also provides support for polling connectors with a work item and for
  50  * generic hotplug interrupt handling where the driver doesn't or cannot keep
  51  * track of a per-connector hpd interrupt.
  52  *
  53  * This helper library can be used independently of the modeset helper library.
  54  * Drivers can also overwrite different parts e.g. use their own hotplug
  55  * handling code to avoid probing unrelated outputs.
  56  *
  57  * The probe helpers share the function table structures with other display
  58  * helper libraries. See struct &drm_connector_helper_funcs for the details.
  59  */
  60
  61 static bool drm_kms_helper_poll = true;
  62 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
  63
  64 static enum drm_mode_status
  65 drm_mode_validate_flag(const struct drm_display_mode *mode,
  66                        int flags)
  67 {
  68         if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
  69             !(flags & DRM_MODE_FLAG_INTERLACE))
  70                 return MODE_NO_INTERLACE;
  71
  72         if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
  73             !(flags & DRM_MODE_FLAG_DBLSCAN))
  74                 return MODE_NO_DBLESCAN;
  75
  76         if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
  77             !(flags & DRM_MODE_FLAG_3D_MASK))
  78                 return MODE_NO_STEREO;
  79
  80         return MODE_OK;
  81 }
  82
  83 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
  84 {
  85         struct drm_cmdline_mode *cmdline_mode;
  86         struct drm_display_mode *mode;
  87
  88         cmdline_mode = &connector->cmdline_mode;
  89         if (!cmdline_mode->specified)
  90                 return 0;
  91
  92         /* Only add a GTF mode if we find no matching probed modes */
  93         list_for_each_entry(mode, &connector->probed_modes, head) {
  94                 if (mode->hdisplay != cmdline_mode->xres ||
  95                     mode->vdisplay != cmdline_mode->yres)
  96                         continue;
  97
  98                 if (cmdline_mode->refresh_specified) {
  99                         /* The probed mode's vrefresh is set until later */
 100                         if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
 101                                 continue;
 102                 }
 103
 104                 return 0;
 105         }
 106
 107         mode = drm_mode_create_from_cmdline_mode(connector->dev,
 108                                                  cmdline_mode);
 109         if (mode == NULL)
 110                 return 0;
 111
 112         drm_mode_probed_add(connector, mode);
 113         return 1;
 114 }
 115
 116 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
 117 /**
 118  * drm_kms_helper_poll_enable_locked - re-enable output polling.
 119  * @dev: drm_device
 120  *
 121  * This function re-enables the output polling work without
 122  * locking the mode_config mutex.
 123  *
 124  * This is like drm_kms_helper_poll_enable() however it is to be
 125  * called from a context where the mode_config mutex is locked
 126  * already.
 127  */
 128 void drm_kms_helper_poll_enable_locked(struct drm_device *dev)
 129 {
 130         bool poll = false;
 131         struct drm_connector *connector;
 132         unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
 133
 134         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 135
 136         if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
 137                 return;
 138
 139         drm_for_each_connector(connector, dev) {
 140                 if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
 141                                          DRM_CONNECTOR_POLL_DISCONNECT))
 142                         poll = true;
 143         }
 144
 145         if (dev->mode_config.delayed_event) {
 146                 poll = true;
 147                 delay = 0;
 148         }
 149
 150         if (poll)
 151                 schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
 152 }
 153 EXPORT_SYMBOL(drm_kms_helper_poll_enable_locked);
 154
 155 /**
 156  * drm_helper_probe_single_connector_modes - get complete set of display modes
 157  * @connector: connector to probe
 158  * @maxX: max width for modes
 159  * @maxY: max height for modes
 160  *
 161  * Based on the helper callbacks implemented by @connector in struct
 162  * &drm_connector_helper_funcs try to detect all valid modes.  Modes will first
 163  * be added to the connector's probed_modes list, then culled (based on validity
 164  * and the @maxX, @maxY parameters) and put into the normal modes list.
 165  *
 166  * Intended to be used as a generic implementation of the ->fill_modes()
 167  * @connector vfunc for drivers that use the CRTC helpers for output mode
 168  * filtering and detection.
 169  *
 170  * The basic procedure is as follows
 171  *
 172  * 1. All modes currently on the connector's modes list are marked as stale
 173  *
 174  * 2. New modes are added to the connector's probed_modes list with
 175  *    drm_mode_probed_add(). New modes start their life with status as OK.
 176  *    Modes are added from a single source using the following priority order.
 177  *
 178  *    - debugfs 'override_edid' (used for testing only)
 179  *    - firmware EDID (drm_load_edid_firmware())
 180  *    - connector helper ->get_modes() vfunc
 181  *    - if the connector status is connector_status_connected, standard
 182  *      VESA DMT modes up to 1024x768 are automatically added
 183  *      (drm_add_modes_noedid())
 184  *
 185  *    Finally modes specified via the kernel command line (video=...) are
 186  *    added in addition to what the earlier probes produced
 187  *    (drm_helper_probe_add_cmdline_mode()). These modes are generated
 188  *    using the VESA GTF/CVT formulas.
 189  *
 190  * 3. Modes are moved from the probed_modes list to the modes list. Potential
 191  *    duplicates are merged together (see drm_mode_connector_list_update()).
 192  *    After this step the probed_modes list will be empty again.
 193  *
 194  * 4. Any non-stale mode on the modes list then undergoes validation
 195  *
 196  *    - drm_mode_validate_basic() performs basic sanity checks
 197  *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
 198  *      (if specified)
 199  *    - drm_mode_validate_flag() checks the modes againt basic connector
 200  *      capabilites (interlace_allowed,doublescan_allowed,stereo_allowed)
 201  *    - the optional connector ->mode_valid() helper can perform driver and/or
 202  *      hardware specific checks
 203  *
 204  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
 205  *    accompanied by a debug message indicating the reason for the mode's
 206  *    rejection (see drm_mode_prune_invalid()).
 207  *
 208  * Returns:
 209  * The number of modes found on @connector.
 210  */
 211 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 212                                             uint32_t maxX, uint32_t maxY)
 213 {
 214         struct drm_device *dev = connector->dev;
 215         struct drm_display_mode *mode;
 216         const struct drm_connector_helper_funcs *connector_funcs =
 217                 connector->helper_private;
 218         int count = 0;
 219         int mode_flags = 0;
 220         bool verbose_prune = true;
 221         enum drm_connector_status old_status;
 222
 223         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 224
 225         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
 226                         connector->name);
 227         /* set all old modes to the stale state */
 228         list_for_each_entry(mode, &connector->modes, head)
 229                 mode->status = MODE_STALE;
 230
 231         old_status = connector->status;
 232
 233         if (connector->force) {
 234                 if (connector->force == DRM_FORCE_ON ||
 235                     connector->force == DRM_FORCE_ON_DIGITAL)
 236                         connector->status = connector_status_connected;
 237                 else
 238                         connector->status = connector_status_disconnected;
 239                 if (connector->funcs->force)
 240                         connector->funcs->force(connector);
 241         } else {
 242                 connector->status = connector->funcs->detect(connector, true);
 243         }
 244
 245         /*
 246          * Normally either the driver's hpd code or the poll loop should
 247          * pick up any changes and fire the hotplug event. But if
 248          * userspace sneaks in a probe, we might miss a change. Hence
 249          * check here, and if anything changed start the hotplug code.
 250          */
 251         if (old_status != connector->status) {
 252                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 253                               connector->base.id,
 254                               connector->name,
 255                               drm_get_connector_status_name(old_status),
 256                               drm_get_connector_status_name(connector->status));
 257
 258                 /*
 259                  * The hotplug event code might call into the fb
 260                  * helpers, and so expects that we do not hold any
 261                  * locks. Fire up the poll struct instead, it will
 262                  * disable itself again.
 263                  */
 264                 dev->mode_config.delayed_event = true;
 265                 if (dev->mode_config.poll_enabled)
 266                         schedule_delayed_work(&dev->mode_config.output_poll_work,
 267                                               0);
 268         }
 269
 270         /* Re-enable polling in case the global poll config changed. */
 271         if (drm_kms_helper_poll != dev->mode_config.poll_running)
 272                 drm_kms_helper_poll_enable_locked(dev);
 273
 274         dev->mode_config.poll_running = drm_kms_helper_poll;
 275
 276         if (connector->status == connector_status_disconnected) {
 277                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
 278                         connector->base.id, connector->name);
 279                 drm_mode_connector_update_edid_property(connector, NULL);
 280                 verbose_prune = false;
 281                 goto prune;
 282         }
 283
 284         if (connector->override_edid) {
 285                 struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
 286
 287                 count = drm_add_edid_modes(connector, edid);
 288                 drm_edid_to_eld(connector, edid);
 289         } else {
 290                 count = drm_load_edid_firmware(connector);
 291                 if (count == 0)
 292                         count = (*connector_funcs->get_modes)(connector);
 293         }
 294
 295         if (count == 0 && connector->status == connector_status_connected)
 296                 count = drm_add_modes_noedid(connector, 1024, 768);
 297         count += drm_helper_probe_add_cmdline_mode(connector);
 298         if (count == 0)
 299                 goto prune;
 300
 301         drm_mode_connector_list_update(connector);
 302
 303         if (connector->interlace_allowed)
 304                 mode_flags |= DRM_MODE_FLAG_INTERLACE;
 305         if (connector->doublescan_allowed)
 306                 mode_flags |= DRM_MODE_FLAG_DBLSCAN;
 307         if (connector->stereo_allowed)
 308                 mode_flags |= DRM_MODE_FLAG_3D_MASK;
 309
 310         list_for_each_entry(mode, &connector->modes, head) {
 311                 if (mode->status == MODE_OK)
 312                         mode->status = drm_mode_validate_basic(mode);
 313
 314                 if (mode->status == MODE_OK)
 315                         mode->status = drm_mode_validate_size(mode, maxX, maxY);
 316
 317                 if (mode->status == MODE_OK)
 318                         mode->status = drm_mode_validate_flag(mode, mode_flags);
 319
 320                 if (mode->status == MODE_OK && connector_funcs->mode_valid)
 321                         mode->status = connector_funcs->mode_valid(connector,
 322                                                                    mode);
 323         }
 324
 325 prune:
 326         drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
 327
 328         if (list_empty(&connector->modes))
 329                 return 0;
 330
 331         list_for_each_entry(mode, &connector->modes, head)
 332                 mode->vrefresh = drm_mode_vrefresh(mode);
 333
 334         drm_mode_sort(&connector->modes);
 335
 336         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
 337                         connector->name);
 338         list_for_each_entry(mode, &connector->modes, head) {
 339                 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
 340                 drm_mode_debug_printmodeline(mode);
 341         }
 342
 343         return count;
 344 }
 345 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
 346
 347 /**
 348  * drm_kms_helper_hotplug_event - fire off KMS hotplug events
 349  * @dev: drm_device whose connector state changed
 350  *
 351  * This function fires off the uevent for userspace and also calls the
 352  * output_poll_changed function, which is most commonly used to inform the fbdev
 353  * emulation code and allow it to update the fbcon output configuration.
 354  *
 355  * Drivers should call this from their hotplug handling code when a change is
 356  * detected. Note that this function does not do any output detection of its
 357  * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
 358  * driver already.
 359  *
 360  * This function must be called from process context with no mode
 361  * setting locks held.
 362  */
 363 void drm_kms_helper_hotplug_event(struct drm_device *dev)
 364 {
 365         /* send a uevent + call fbdev */
 366         drm_sysfs_hotplug_event(dev);
 367         if (dev->mode_config.funcs->output_poll_changed)
 368                 dev->mode_config.funcs->output_poll_changed(dev);
 369 }
 370 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 371
 372 static void output_poll_execute(struct work_struct *work)
 373 {
 374         struct delayed_work *delayed_work = to_delayed_work(work);
 375         struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
 376         struct drm_connector *connector;
 377         enum drm_connector_status old_status;
 378         bool repoll = false, changed;
 379
 380         /* Pick up any changes detected by the probe functions. */
 381         changed = dev->mode_config.delayed_event;
 382         dev->mode_config.delayed_event = false;
 383
 384         if (!drm_kms_helper_poll)
 385                 goto out;
 386
 387         mutex_lock(&dev->mode_config.mutex);
 388         drm_for_each_connector(connector, dev) {
 389
 390                 /* Ignore forced connectors. */
 391                 if (connector->force)
 392                         continue;
 393
 394                 /* Ignore HPD capable connectors and connectors where we don't
 395                  * want any hotplug detection at all for polling. */
 396                 if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
 397                         continue;
 398
 399                 old_status = connector->status;
 400                 /* if we are connected and don't want to poll for disconnect
 401                    skip it */
 402                 if (old_status == connector_status_connected &&
 403                     !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
 404                         continue;
 405
 406                 repoll = true;
 407
 408                 connector->status = connector->funcs->detect(connector, false);
 409                 if (old_status != connector->status) {
 410                         const char *old, *new;
 411
 412                         /*
 413                          * The poll work sets force=false when calling detect so
 414                          * that drivers can avoid to do disruptive tests (e.g.
 415                          * when load detect cycles could cause flickering on
 416                          * other, running displays). This bears the risk that we
 417                          * flip-flop between unknown here in the poll work and
 418                          * the real state when userspace forces a full detect
 419                          * call after receiving a hotplug event due to this
 420                          * change.
 421                          *
 422                          * Hence clamp an unknown detect status to the old
 423                          * value.
 424                          */
 425                         if (connector->status == connector_status_unknown) {
 426                                 connector->status = old_status;
 427                                 continue;
 428                         }
 429
 430                         old = drm_get_connector_status_name(old_status);
 431                         new = drm_get_connector_status_name(connector->status);
 432
 433                         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
 434                                       "status updated from %s to %s\n",
 435                                       connector->base.id,
 436                                       connector->name,
 437                                       old, new);
 438
 439                         changed = true;
 440                 }
 441         }
 442
 443         mutex_unlock(&dev->mode_config.mutex);
 444
 445 out:
 446         if (changed)
 447                 drm_kms_helper_hotplug_event(dev);
 448
 449         if (repoll)
 450                 schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
 451 }
 452
 453 /**
 454  * drm_kms_helper_poll_disable - disable output polling
 455  * @dev: drm_device
 456  *
 457  * This function disables the output polling work.
 458  *
 459  * Drivers can call this helper from their device suspend implementation. It is
 460  * not an error to call this even when output polling isn't enabled or arlready
 461  * disabled.
 462  */
 463 void drm_kms_helper_poll_disable(struct drm_device *dev)
 464 {
 465         if (!dev->mode_config.poll_enabled)
 466                 return;
 467         cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 468 }
 469 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
 470
 471 /**
 472  * drm_kms_helper_poll_enable - re-enable output polling.
 473  * @dev: drm_device
 474  *
 475  * This function re-enables the output polling work.
 476  *
 477  * Drivers can call this helper from their device resume implementation. It is
 478  * an error to call this when the output polling support has not yet been set
 479  * up.
 480  */
 481 void drm_kms_helper_poll_enable(struct drm_device *dev)
 482 {
 483         mutex_lock(&dev->mode_config.mutex);
 484         drm_kms_helper_poll_enable_locked(dev);
 485         mutex_unlock(&dev->mode_config.mutex);
 486 }
 487 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
 488
 489 /**
 490  * drm_kms_helper_poll_init - initialize and enable output polling
 491  * @dev: drm_device
 492  *
 493  * This function intializes and then also enables output polling support for
 494  * @dev. Drivers which do not have reliable hotplug support in hardware can use
 495  * this helper infrastructure to regularly poll such connectors for changes in
 496  * their connection state.
 497  *
 498  * Drivers can control which connectors are polled by setting the
 499  * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
 500  * connectors where probing live outputs can result in visual distortion drivers
 501  * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
 502  * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
 503  * completely ignored by the polling logic.
 504  *
 505  * Note that a connector can be both polled and probed from the hotplug handler,
 506  * in case the hotplug interrupt is known to be unreliable.
 507  */
 508 void drm_kms_helper_poll_init(struct drm_device *dev)
 509 {
 510         INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
 511         dev->mode_config.poll_enabled = true;
 512
 513         drm_kms_helper_poll_enable(dev);
 514 }
 515 EXPORT_SYMBOL(drm_kms_helper_poll_init);
 516
 517 /**
 518  * drm_kms_helper_poll_fini - disable output polling and clean it up
 519  * @dev: drm_device
 520  */
 521 void drm_kms_helper_poll_fini(struct drm_device *dev)
 522 {
 523         drm_kms_helper_poll_disable(dev);
 524 }
 525 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
 526
 527 /**
 528  * drm_helper_hpd_irq_event - hotplug processing
 529  * @dev: drm_device
 530  *
 531  * Drivers can use this helper function to run a detect cycle on all connectors
 532  * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
 533  * other connectors are ignored, which is useful to avoid reprobing fixed
 534  * panels.
 535  *
 536  * This helper function is useful for drivers which can't or don't track hotplug
 537  * interrupts for each connector.
 538  *
 539  * Drivers which support hotplug interrupts for each connector individually and
 540  * which have a more fine-grained detect logic should bypass this code and
 541  * directly call drm_kms_helper_hotplug_event() in case the connector state
 542  * changed.
 543  *
 544  * This function must be called from process context with no mode
 545  * setting locks held.
 546  *
 547  * Note that a connector can be both polled and probed from the hotplug handler,
 548  * in case the hotplug interrupt is known to be unreliable.
 549  */
 550 bool drm_helper_hpd_irq_event(struct drm_device *dev)
 551 {
 552         struct drm_connector *connector;
 553         enum drm_connector_status old_status;
 554         bool changed = false;
 555
 556         if (!dev->mode_config.poll_enabled)
 557                 return false;
 558
 559         mutex_lock(&dev->mode_config.mutex);
 560         drm_for_each_connector(connector, dev) {
 561
 562                 /* Only handle HPD capable connectors. */
 563                 if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
 564                         continue;
 565
 566                 old_status = connector->status;
 567
 568                 connector->status = connector->funcs->detect(connector, false);
 569                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 570                               connector->base.id,
 571                               connector->name,
 572                               drm_get_connector_status_name(old_status),
 573                               drm_get_connector_status_name(connector->status));
 574                 if (old_status != connector->status)
 575                         changed = true;
 576         }
 577
 578         mutex_unlock(&dev->mode_config.mutex);
 579
 580         if (changed)
 581                 drm_kms_helper_hotplug_event(dev);
 582
 583         return changed;
 584 }
 585 EXPORT_SYMBOL(drm_helper_hpd_irq_event);