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/drm_bridge.h>
  36 #include <drm/drm_client.h>
  37 #include <drm/drm_crtc.h>
  38 #include <drm/drm_edid.h>
  39 #include <drm/drm_fb_helper.h>
  40 #include <drm/drm_fourcc.h>
  41 #include <drm/drm_modeset_helper_vtables.h>
  42 #include <drm/drm_print.h>
  43 #include <drm/drm_probe_helper.h>
  44 #include <drm/drm_sysfs.h>
  45
  46 #include "drm_crtc_helper_internal.h"
  47
  48 /**
  49  * DOC: output probing helper overview
  50  *
  51  * This library provides some helper code for output probing. It provides an
  52  * implementation of the core &drm_connector_funcs.fill_modes interface with
  53  * drm_helper_probe_single_connector_modes().
  54  *
  55  * It also provides support for polling connectors with a work item and for
  56  * generic hotplug interrupt handling where the driver doesn't or cannot keep
  57  * track of a per-connector hpd interrupt.
  58  *
  59  * This helper library can be used independently of the modeset helper library.
  60  * Drivers can also overwrite different parts e.g. use their own hotplug
  61  * handling code to avoid probing unrelated outputs.
  62  *
  63  * The probe helpers share the function table structures with other display
  64  * helper libraries. See &struct drm_connector_helper_funcs for the details.
  65  */
  66
  67 static bool drm_kms_helper_poll = true;
  68 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
  69
  70 static enum drm_mode_status
  71 drm_mode_validate_flag(const struct drm_display_mode *mode,
  72                        int flags)
  73 {
  74         if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
  75             !(flags & DRM_MODE_FLAG_INTERLACE))
  76                 return MODE_NO_INTERLACE;
  77
  78         if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
  79             !(flags & DRM_MODE_FLAG_DBLSCAN))
  80                 return MODE_NO_DBLESCAN;
  81
  82         if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
  83             !(flags & DRM_MODE_FLAG_3D_MASK))
  84                 return MODE_NO_STEREO;
  85
  86         return MODE_OK;
  87 }
  88
  89 static int
  90 drm_mode_validate_pipeline(struct drm_display_mode *mode,
  91                            struct drm_connector *connector,
  92                            struct drm_modeset_acquire_ctx *ctx,
  93                            enum drm_mode_status *status)
  94 {
  95         struct drm_device *dev = connector->dev;
  96         struct drm_encoder *encoder;
  97         int ret;
  98
  99         /* Step 1: Validate against connector */
 100         ret = drm_connector_mode_valid(connector, mode, ctx, status);
 101         if (ret || *status != MODE_OK)
 102                 return ret;
 103
 104         /* Step 2: Validate against encoders and crtcs */
 105         drm_connector_for_each_possible_encoder(connector, encoder) {
 106                 struct drm_bridge *bridge;
 107                 struct drm_crtc *crtc;
 108
 109                 *status = drm_encoder_mode_valid(encoder, mode);
 110                 if (*status != MODE_OK) {
 111                         /* No point in continuing for crtc check as this encoder
 112                          * will not accept the mode anyway. If all encoders
 113                          * reject the mode then, at exit, ret will not be
 114                          * MODE_OK. */
 115                         continue;
 116                 }
 117
 118                 bridge = drm_bridge_chain_get_first_bridge(encoder);
 119                 *status = drm_bridge_chain_mode_valid(bridge,
 120                                                       &connector->display_info,
 121                                                       mode);
 122                 if (*status != MODE_OK) {
 123                         /* There is also no point in continuing for crtc check
 124                          * here. */
 125                         continue;
 126                 }
 127
 128                 drm_for_each_crtc(crtc, dev) {
 129                         if (!drm_encoder_crtc_ok(encoder, crtc))
 130                                 continue;
 131
 132                         *status = drm_crtc_mode_valid(crtc, mode);
 133                         if (*status == MODE_OK) {
 134                                 /* If we get to this point there is at least
 135                                  * one combination of encoder+crtc that works
 136                                  * for this mode. Lets return now. */
 137                                 return 0;
 138                         }
 139                 }
 140         }
 141
 142         return 0;
 143 }
 144
 145 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 146 {
 147         struct drm_cmdline_mode *cmdline_mode;
 148         struct drm_display_mode *mode;
 149
 150         cmdline_mode = &connector->cmdline_mode;
 151         if (!cmdline_mode->specified)
 152                 return 0;
 153
 154         /* Only add a GTF mode if we find no matching probed modes */
 155         list_for_each_entry(mode, &connector->probed_modes, head) {
 156                 if (mode->hdisplay != cmdline_mode->xres ||
 157                     mode->vdisplay != cmdline_mode->yres)
 158                         continue;
 159
 160                 if (cmdline_mode->refresh_specified) {
 161                         /* The probed mode's vrefresh is set until later */
 162                         if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
 163                                 continue;
 164                 }
 165
 166                 /* Mark the matching mode as being preferred by the user */
 167                 mode->type |= DRM_MODE_TYPE_USERDEF;
 168                 return 0;
 169         }
 170
 171         mode = drm_mode_create_from_cmdline_mode(connector->dev,
 172                                                  cmdline_mode);
 173         if (mode == NULL)
 174                 return 0;
 175
 176         drm_mode_probed_add(connector, mode);
 177         return 1;
 178 }
 179
 180 enum drm_mode_status drm_crtc_mode_valid(struct drm_crtc *crtc,
 181                                          const struct drm_display_mode *mode)
 182 {
 183         const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
 184
 185         if (!crtc_funcs || !crtc_funcs->mode_valid)
 186                 return MODE_OK;
 187
 188         return crtc_funcs->mode_valid(crtc, mode);
 189 }
 190
 191 enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder,
 192                                             const struct drm_display_mode *mode)
 193 {
 194         const struct drm_encoder_helper_funcs *encoder_funcs =
 195                 encoder->helper_private;
 196
 197         if (!encoder_funcs || !encoder_funcs->mode_valid)
 198                 return MODE_OK;
 199
 200         return encoder_funcs->mode_valid(encoder, mode);
 201 }
 202
 203 int
 204 drm_connector_mode_valid(struct drm_connector *connector,
 205                          struct drm_display_mode *mode,
 206                          struct drm_modeset_acquire_ctx *ctx,
 207                          enum drm_mode_status *status)
 208 {
 209         const struct drm_connector_helper_funcs *connector_funcs =
 210                 connector->helper_private;
 211         int ret = 0;
 212
 213         if (!connector_funcs)
 214                 *status = MODE_OK;
 215         else if (connector_funcs->mode_valid_ctx)
 216                 ret = connector_funcs->mode_valid_ctx(connector, mode, ctx,
 217                                                       status);
 218         else if (connector_funcs->mode_valid)
 219                 *status = connector_funcs->mode_valid(connector, mode);
 220         else
 221                 *status = MODE_OK;
 222
 223         return ret;
 224 }
 225
 226 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
 227 /**
 228  * drm_kms_helper_poll_enable - re-enable output polling.
 229  * @dev: drm_device
 230  *
 231  * This function re-enables the output polling work, after it has been
 232  * temporarily disabled using drm_kms_helper_poll_disable(), for example over
 233  * suspend/resume.
 234  *
 235  * Drivers can call this helper from their device resume implementation. It is
 236  * not an error to call this even when output polling isn't enabled.
 237  *
 238  * Note that calls to enable and disable polling must be strictly ordered, which
 239  * is automatically the case when they're only call from suspend/resume
 240  * callbacks.
 241  */
 242 void drm_kms_helper_poll_enable(struct drm_device *dev)
 243 {
 244         bool poll = false;
 245         struct drm_connector *connector;
 246         struct drm_connector_list_iter conn_iter;
 247         unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
 248
 249         if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
 250                 return;
 251
 252         drm_connector_list_iter_begin(dev, &conn_iter);
 253         drm_for_each_connector_iter(connector, &conn_iter) {
 254                 if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
 255                                          DRM_CONNECTOR_POLL_DISCONNECT))
 256                         poll = true;
 257         }
 258         drm_connector_list_iter_end(&conn_iter);
 259
 260         if (dev->mode_config.delayed_event) {
 261                 /*
 262                  * FIXME:
 263                  *
 264                  * Use short (1s) delay to handle the initial delayed event.
 265                  * This delay should not be needed, but Optimus/nouveau will
 266                  * fail in a mysterious way if the delayed event is handled as
 267                  * soon as possible like it is done in
 268                  * drm_helper_probe_single_connector_modes() in case the poll
 269                  * was enabled before.
 270                  */
 271                 poll = true;
 272                 delay = HZ;
 273         }
 274
 275         if (poll)
 276                 schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
 277 }
 278 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
 279
 280 static enum drm_connector_status
 281 drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
 282 {
 283         const struct drm_connector_helper_funcs *funcs = connector->helper_private;
 284         struct drm_modeset_acquire_ctx ctx;
 285         int ret;
 286
 287         drm_modeset_acquire_init(&ctx, 0);
 288
 289 retry:
 290         ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
 291         if (!ret) {
 292                 if (funcs->detect_ctx)
 293                         ret = funcs->detect_ctx(connector, &ctx, force);
 294                 else if (connector->funcs->detect)
 295                         ret = connector->funcs->detect(connector, force);
 296                 else
 297                         ret = connector_status_connected;
 298         }
 299
 300         if (ret == -EDEADLK) {
 301                 drm_modeset_backoff(&ctx);
 302                 goto retry;
 303         }
 304
 305         if (WARN_ON(ret < 0))
 306                 ret = connector_status_unknown;
 307
 308         if (ret != connector->status)
 309                 connector->epoch_counter += 1;
 310
 311         drm_modeset_drop_locks(&ctx);
 312         drm_modeset_acquire_fini(&ctx);
 313
 314         return ret;
 315 }
 316
 317 /**
 318  * drm_helper_probe_detect - probe connector status
 319  * @connector: connector to probe
 320  * @ctx: acquire_ctx, or NULL to let this function handle locking.
 321  * @force: Whether destructive probe operations should be performed.
 322  *
 323  * This function calls the detect callbacks of the connector.
 324  * This function returns &drm_connector_status, or
 325  * if @ctx is set, it might also return -EDEADLK.
 326  */
 327 int
 328 drm_helper_probe_detect(struct drm_connector *connector,
 329                         struct drm_modeset_acquire_ctx *ctx,
 330                         bool force)
 331 {
 332         const struct drm_connector_helper_funcs *funcs = connector->helper_private;
 333         struct drm_device *dev = connector->dev;
 334         int ret;
 335
 336         if (!ctx)
 337                 return drm_helper_probe_detect_ctx(connector, force);
 338
 339         ret = drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
 340         if (ret)
 341                 return ret;
 342
 343         if (funcs->detect_ctx)
 344                 ret = funcs->detect_ctx(connector, ctx, force);
 345         else if (connector->funcs->detect)
 346                 ret = connector->funcs->detect(connector, force);
 347         else
 348                 ret = connector_status_connected;
 349
 350         if (ret != connector->status)
 351                 connector->epoch_counter += 1;
 352
 353         return ret;
 354 }
 355 EXPORT_SYMBOL(drm_helper_probe_detect);
 356
 357 /**
 358  * drm_helper_probe_single_connector_modes - get complete set of display modes
 359  * @connector: connector to probe
 360  * @maxX: max width for modes
 361  * @maxY: max height for modes
 362  *
 363  * Based on the helper callbacks implemented by @connector in struct
 364  * &drm_connector_helper_funcs try to detect all valid modes.  Modes will first
 365  * be added to the connector's probed_modes list, then culled (based on validity
 366  * and the @maxX, @maxY parameters) and put into the normal modes list.
 367  *
 368  * Intended to be used as a generic implementation of the
 369  * &drm_connector_funcs.fill_modes() vfunc for drivers that use the CRTC helpers
 370  * for output mode filtering and detection.
 371  *
 372  * The basic procedure is as follows
 373  *
 374  * 1. All modes currently on the connector's modes list are marked as stale
 375  *
 376  * 2. New modes are added to the connector's probed_modes list with
 377  *    drm_mode_probed_add(). New modes start their life with status as OK.
 378  *    Modes are added from a single source using the following priority order.
 379  *
 380  *    - &drm_connector_helper_funcs.get_modes vfunc
 381  *    - if the connector status is connector_status_connected, standard
 382  *      VESA DMT modes up to 1024x768 are automatically added
 383  *      (drm_add_modes_noedid())
 384  *
 385  *    Finally modes specified via the kernel command line (video=...) are
 386  *    added in addition to what the earlier probes produced
 387  *    (drm_helper_probe_add_cmdline_mode()). These modes are generated
 388  *    using the VESA GTF/CVT formulas.
 389  *
 390  * 3. Modes are moved from the probed_modes list to the modes list. Potential
 391  *    duplicates are merged together (see drm_connector_list_update()).
 392  *    After this step the probed_modes list will be empty again.
 393  *
 394  * 4. Any non-stale mode on the modes list then undergoes validation
 395  *
 396  *    - drm_mode_validate_basic() performs basic sanity checks
 397  *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
 398  *      (if specified)
 399  *    - drm_mode_validate_flag() checks the modes against basic connector
 400  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
 401  *    - the optional &drm_connector_helper_funcs.mode_valid or
 402  *      &drm_connector_helper_funcs.mode_valid_ctx helpers can perform driver
 403  *      and/or sink specific checks
 404  *    - the optional &drm_crtc_helper_funcs.mode_valid,
 405  *      &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid
 406  *      helpers can perform driver and/or source specific checks which are also
 407  *      enforced by the modeset/atomic helpers
 408  *
 409  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
 410  *    accompanied by a debug message indicating the reason for the mode's
 411  *    rejection (see drm_mode_prune_invalid()).
 412  *
 413  * Returns:
 414  * The number of modes found on @connector.
 415  */
 416 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 417                                             uint32_t maxX, uint32_t maxY)
 418 {
 419         struct drm_device *dev = connector->dev;
 420         struct drm_display_mode *mode;
 421         const struct drm_connector_helper_funcs *connector_funcs =
 422                 connector->helper_private;
 423         int count = 0, ret;
 424         int mode_flags = 0;
 425         bool verbose_prune = true;
 426         enum drm_connector_status old_status;
 427         struct drm_modeset_acquire_ctx ctx;
 428
 429         WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
 430
 431         drm_modeset_acquire_init(&ctx, 0);
 432
 433         DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
 434                         connector->name);
 435
 436 retry:
 437         ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
 438         if (ret == -EDEADLK) {
 439                 drm_modeset_backoff(&ctx);
 440                 goto retry;
 441         } else
 442                 WARN_ON(ret < 0);
 443
 444         /* set all old modes to the stale state */
 445         list_for_each_entry(mode, &connector->modes, head)
 446                 mode->status = MODE_STALE;
 447
 448         old_status = connector->status;
 449
 450         if (connector->force) {
 451                 if (connector->force == DRM_FORCE_ON ||
 452                     connector->force == DRM_FORCE_ON_DIGITAL)
 453                         connector->status = connector_status_connected;
 454                 else
 455                         connector->status = connector_status_disconnected;
 456                 if (connector->funcs->force)
 457                         connector->funcs->force(connector);
 458         } else {
 459                 ret = drm_helper_probe_detect(connector, &ctx, true);
 460
 461                 if (ret == -EDEADLK) {
 462                         drm_modeset_backoff(&ctx);
 463                         goto retry;
 464                 } else if (WARN(ret < 0, "Invalid return value %i for connector detection\n", ret))
 465                         ret = connector_status_unknown;
 466
 467                 connector->status = ret;
 468         }
 469
 470         /*
 471          * Normally either the driver's hpd code or the poll loop should
 472          * pick up any changes and fire the hotplug event. But if
 473          * userspace sneaks in a probe, we might miss a change. Hence
 474          * check here, and if anything changed start the hotplug code.
 475          */
 476         if (old_status != connector->status) {
 477                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 478                               connector->base.id,
 479                               connector->name,
 480                               drm_get_connector_status_name(old_status),
 481                               drm_get_connector_status_name(connector->status));
 482
 483                 /*
 484                  * The hotplug event code might call into the fb
 485                  * helpers, and so expects that we do not hold any
 486                  * locks. Fire up the poll struct instead, it will
 487                  * disable itself again.
 488                  */
 489                 dev->mode_config.delayed_event = true;
 490                 if (dev->mode_config.poll_enabled)
 491                         schedule_delayed_work(&dev->mode_config.output_poll_work,
 492                                               0);
 493         }
 494
 495         /* Re-enable polling in case the global poll config changed. */
 496         if (drm_kms_helper_poll != dev->mode_config.poll_running)
 497                 drm_kms_helper_poll_enable(dev);
 498
 499         dev->mode_config.poll_running = drm_kms_helper_poll;
 500
 501         if (connector->status == connector_status_disconnected) {
 502                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
 503                         connector->base.id, connector->name);
 504                 drm_connector_update_edid_property(connector, NULL);
 505                 verbose_prune = false;
 506                 goto prune;
 507         }
 508
 509         count = (*connector_funcs->get_modes)(connector);
 510
 511         /*
 512          * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
 513          * override/firmware EDID.
 514          */
 515         if (count == 0 && connector->status == connector_status_connected)
 516                 count = drm_add_override_edid_modes(connector);
 517
 518         if (count == 0 && connector->status == connector_status_connected)
 519                 count = drm_add_modes_noedid(connector, 1024, 768);
 520         count += drm_helper_probe_add_cmdline_mode(connector);
 521         if (count == 0)
 522                 goto prune;
 523
 524         drm_connector_list_update(connector);
 525
 526         if (connector->interlace_allowed)
 527                 mode_flags |= DRM_MODE_FLAG_INTERLACE;
 528         if (connector->doublescan_allowed)
 529                 mode_flags |= DRM_MODE_FLAG_DBLSCAN;
 530         if (connector->stereo_allowed)
 531                 mode_flags |= DRM_MODE_FLAG_3D_MASK;
 532
 533         list_for_each_entry(mode, &connector->modes, head) {
 534                 if (mode->status != MODE_OK)
 535                         continue;
 536
 537                 mode->status = drm_mode_validate_driver(dev, mode);
 538                 if (mode->status != MODE_OK)
 539                         continue;
 540
 541                 mode->status = drm_mode_validate_size(mode, maxX, maxY);
 542                 if (mode->status != MODE_OK)
 543                         continue;
 544
 545                 mode->status = drm_mode_validate_flag(mode, mode_flags);
 546                 if (mode->status != MODE_OK)
 547                         continue;
 548
 549                 ret = drm_mode_validate_pipeline(mode, connector, &ctx,
 550                                                  &mode->status);
 551                 if (ret) {
 552                         drm_dbg_kms(dev,
 553                                     "drm_mode_validate_pipeline failed: %d\n",
 554                                     ret);
 555
 556                         if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK)) {
 557                                 mode->status = MODE_ERROR;
 558                         } else {
 559                                 drm_modeset_backoff(&ctx);
 560                                 goto retry;
 561                         }
 562                 }
 563
 564                 if (mode->status != MODE_OK)
 565                         continue;
 566                 mode->status = drm_mode_validate_ycbcr420(mode, connector);
 567         }
 568
 569 prune:
 570         drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
 571
 572         drm_modeset_drop_locks(&ctx);
 573         drm_modeset_acquire_fini(&ctx);
 574
 575         if (list_empty(&connector->modes))
 576                 return 0;
 577
 578         drm_mode_sort(&connector->modes);
 579
 580         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
 581                         connector->name);
 582         list_for_each_entry(mode, &connector->modes, head) {
 583                 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
 584                 drm_mode_debug_printmodeline(mode);
 585         }
 586
 587         return count;
 588 }
 589 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
 590
 591 /**
 592  * drm_kms_helper_hotplug_event - fire off KMS hotplug events
 593  * @dev: drm_device whose connector state changed
 594  *
 595  * This function fires off the uevent for userspace and also calls the
 596  * output_poll_changed function, which is most commonly used to inform the fbdev
 597  * emulation code and allow it to update the fbcon output configuration.
 598  *
 599  * Drivers should call this from their hotplug handling code when a change is
 600  * detected. Note that this function does not do any output detection of its
 601  * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
 602  * driver already.
 603  *
 604  * This function must be called from process context with no mode
 605  * setting locks held.
 606  */
 607 void drm_kms_helper_hotplug_event(struct drm_device *dev)
 608 {
 609         /* send a uevent + call fbdev */
 610         drm_sysfs_hotplug_event(dev);
 611         if (dev->mode_config.funcs->output_poll_changed)
 612                 dev->mode_config.funcs->output_poll_changed(dev);
 613
 614         drm_client_dev_hotplug(dev);
 615 }
 616 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 617
 618 static void output_poll_execute(struct work_struct *work)
 619 {
 620         struct delayed_work *delayed_work = to_delayed_work(work);
 621         struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
 622         struct drm_connector *connector;
 623         struct drm_connector_list_iter conn_iter;
 624         enum drm_connector_status old_status;
 625         bool repoll = false, changed;
 626
 627         if (!dev->mode_config.poll_enabled)
 628                 return;
 629
 630         /* Pick up any changes detected by the probe functions. */
 631         changed = dev->mode_config.delayed_event;
 632         dev->mode_config.delayed_event = false;
 633
 634         if (!drm_kms_helper_poll)
 635                 goto out;
 636
 637         if (!mutex_trylock(&dev->mode_config.mutex)) {
 638                 repoll = true;
 639                 goto out;
 640         }
 641
 642         drm_connector_list_iter_begin(dev, &conn_iter);
 643         drm_for_each_connector_iter(connector, &conn_iter) {
 644                 /* Ignore forced connectors. */
 645                 if (connector->force)
 646                         continue;
 647
 648                 /* Ignore HPD capable connectors and connectors where we don't
 649                  * want any hotplug detection at all for polling. */
 650                 if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
 651                         continue;
 652
 653                 old_status = connector->status;
 654                 /* if we are connected and don't want to poll for disconnect
 655                    skip it */
 656                 if (old_status == connector_status_connected &&
 657                     !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
 658                         continue;
 659
 660                 repoll = true;
 661
 662                 connector->status = drm_helper_probe_detect(connector, NULL, false);
 663                 if (old_status != connector->status) {
 664                         const char *old, *new;
 665
 666                         /*
 667                          * The poll work sets force=false when calling detect so
 668                          * that drivers can avoid to do disruptive tests (e.g.
 669                          * when load detect cycles could cause flickering on
 670                          * other, running displays). This bears the risk that we
 671                          * flip-flop between unknown here in the poll work and
 672                          * the real state when userspace forces a full detect
 673                          * call after receiving a hotplug event due to this
 674                          * change.
 675                          *
 676                          * Hence clamp an unknown detect status to the old
 677                          * value.
 678                          */
 679                         if (connector->status == connector_status_unknown) {
 680                                 connector->status = old_status;
 681                                 continue;
 682                         }
 683
 684                         old = drm_get_connector_status_name(old_status);
 685                         new = drm_get_connector_status_name(connector->status);
 686
 687                         DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
 688                                       "status updated from %s to %s\n",
 689                                       connector->base.id,
 690                                       connector->name,
 691                                       old, new);
 692
 693                         changed = true;
 694                 }
 695         }
 696         drm_connector_list_iter_end(&conn_iter);
 697
 698         mutex_unlock(&dev->mode_config.mutex);
 699
 700 out:
 701         if (changed)
 702                 drm_kms_helper_hotplug_event(dev);
 703
 704         if (repoll)
 705                 schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
 706 }
 707
 708 /**
 709  * drm_kms_helper_is_poll_worker - is %current task an output poll worker?
 710  *
 711  * Determine if %current task is an output poll worker.  This can be used
 712  * to select distinct code paths for output polling versus other contexts.
 713  *
 714  * One use case is to avoid a deadlock between the output poll worker and
 715  * the autosuspend worker wherein the latter waits for polling to finish
 716  * upon calling drm_kms_helper_poll_disable(), while the former waits for
 717  * runtime suspend to finish upon calling pm_runtime_get_sync() in a
 718  * connector ->detect hook.
 719  */
 720 bool drm_kms_helper_is_poll_worker(void)
 721 {
 722         struct work_struct *work = current_work();
 723
 724         return work && work->func == output_poll_execute;
 725 }
 726 EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
 727
 728 /**
 729  * drm_kms_helper_poll_disable - disable output polling
 730  * @dev: drm_device
 731  *
 732  * This function disables the output polling work.
 733  *
 734  * Drivers can call this helper from their device suspend implementation. It is
 735  * not an error to call this even when output polling isn't enabled or already
 736  * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
 737  *
 738  * Note that calls to enable and disable polling must be strictly ordered, which
 739  * is automatically the case when they're only call from suspend/resume
 740  * callbacks.
 741  */
 742 void drm_kms_helper_poll_disable(struct drm_device *dev)
 743 {
 744         if (!dev->mode_config.poll_enabled)
 745                 return;
 746         cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 747 }
 748 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
 749
 750 /**
 751  * drm_kms_helper_poll_init - initialize and enable output polling
 752  * @dev: drm_device
 753  *
 754  * This function intializes and then also enables output polling support for
 755  * @dev. Drivers which do not have reliable hotplug support in hardware can use
 756  * this helper infrastructure to regularly poll such connectors for changes in
 757  * their connection state.
 758  *
 759  * Drivers can control which connectors are polled by setting the
 760  * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
 761  * connectors where probing live outputs can result in visual distortion drivers
 762  * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
 763  * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
 764  * completely ignored by the polling logic.
 765  *
 766  * Note that a connector can be both polled and probed from the hotplug handler,
 767  * in case the hotplug interrupt is known to be unreliable.
 768  */
 769 void drm_kms_helper_poll_init(struct drm_device *dev)
 770 {
 771         INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
 772         dev->mode_config.poll_enabled = true;
 773
 774         drm_kms_helper_poll_enable(dev);
 775 }
 776 EXPORT_SYMBOL(drm_kms_helper_poll_init);
 777
 778 /**
 779  * drm_kms_helper_poll_fini - disable output polling and clean it up
 780  * @dev: drm_device
 781  */
 782 void drm_kms_helper_poll_fini(struct drm_device *dev)
 783 {
 784         if (!dev->mode_config.poll_enabled)
 785                 return;
 786
 787         dev->mode_config.poll_enabled = false;
 788         cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
 789 }
 790 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
 791
 792 /**
 793  * drm_helper_hpd_irq_event - hotplug processing
 794  * @dev: drm_device
 795  *
 796  * Drivers can use this helper function to run a detect cycle on all connectors
 797  * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
 798  * other connectors are ignored, which is useful to avoid reprobing fixed
 799  * panels.
 800  *
 801  * This helper function is useful for drivers which can't or don't track hotplug
 802  * interrupts for each connector.
 803  *
 804  * Drivers which support hotplug interrupts for each connector individually and
 805  * which have a more fine-grained detect logic should bypass this code and
 806  * directly call drm_kms_helper_hotplug_event() in case the connector state
 807  * changed.
 808  *
 809  * This function must be called from process context with no mode
 810  * setting locks held.
 811  *
 812  * Note that a connector can be both polled and probed from the hotplug handler,
 813  * in case the hotplug interrupt is known to be unreliable.
 814  */
 815 bool drm_helper_hpd_irq_event(struct drm_device *dev)
 816 {
 817         struct drm_connector *connector;
 818         struct drm_connector_list_iter conn_iter;
 819         enum drm_connector_status old_status;
 820         bool changed = false;
 821         u64 old_epoch_counter;
 822
 823         if (!dev->mode_config.poll_enabled)
 824                 return false;
 825
 826         mutex_lock(&dev->mode_config.mutex);
 827         drm_connector_list_iter_begin(dev, &conn_iter);
 828         drm_for_each_connector_iter(connector, &conn_iter) {
 829                 /* Only handle HPD capable connectors. */
 830                 if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
 831                         continue;
 832
 833                 old_status = connector->status;
 834
 835                 old_epoch_counter = connector->epoch_counter;
 836
 837                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] Old epoch counter %llu\n", connector->base.id,
 838                               connector->name,
 839                               old_epoch_counter);
 840
 841                 connector->status = drm_helper_probe_detect(connector, NULL, false);
 842                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 843                               connector->base.id,
 844                               connector->name,
 845                               drm_get_connector_status_name(old_status),
 846                               drm_get_connector_status_name(connector->status));
 847
 848                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] New epoch counter %llu\n",
 849                               connector->base.id,
 850                               connector->name,
 851                               connector->epoch_counter);
 852
 853                 /*
 854                  * Check if epoch counter had changed, meaning that we need
 855                  * to send a uevent.
 856                  */
 857                 if (old_epoch_counter != connector->epoch_counter)
 858                         changed = true;
 859
 860         }
 861         drm_connector_list_iter_end(&conn_iter);
 862         mutex_unlock(&dev->mode_config.mutex);
 863
 864         if (changed) {
 865                 drm_kms_helper_hotplug_event(dev);
 866                 DRM_DEBUG_KMS("Sent hotplug event\n");
 867         }
 868
 869         return changed;
 870 }
 871 EXPORT_SYMBOL(drm_helper_hpd_irq_event);