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