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