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