1 /* $NetBSD: drm_probe_helper.c,v 1.4 2020/02/14 14:34:57 maya Exp $ */ 2 3 /* 4 * Copyright (c) 2006-2008 Intel Corporation 5 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie> 6 * 7 * DRM core CRTC related functions 8 * 9 * Permission to use, copy, modify, distribute, and sell this software and its 10 * documentation for any purpose is hereby granted without fee, provided that 11 * the above copyright notice appear in all copies and that both that copyright 12 * notice and this permission notice appear in supporting documentation, and 13 * that the name of the copyright holders not be used in advertising or 14 * publicity pertaining to distribution of the software without specific, 15 * written prior permission. The copyright holders make no representations 16 * about the suitability of this software for any purpose. It is provided "as 17 * is" without express or implied warranty. 18 * 19 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, 20 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO 21 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR 22 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, 23 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER 24 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 25 * OF THIS SOFTWARE. 26 * 27 * Authors: 28 * Keith Packard 29 * Eric Anholt <eric@anholt.net> 30 * Dave Airlie <airlied@linux.ie> 31 * Jesse Barnes <jesse.barnes@intel.com> 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: drm_probe_helper.c,v 1.4 2020/02/14 14:34:57 maya Exp $"); 36 37 #include <linux/export.h> 38 #include <linux/moduleparam.h> 39 40 #include <drm/drmP.h> 41 #include <drm/drm_crtc.h> 42 #include <drm/drm_fourcc.h> 43 #include <drm/drm_crtc_helper.h> 44 #include <drm/drm_fb_helper.h> 45 #include <drm/drm_edid.h> 46 47 /** 48 * DOC: output probing helper overview 49 * 50 * This library provides some helper code for output probing. It provides an 51 * implementation of the core connector->fill_modes interface with 52 * drm_helper_probe_single_connector_modes. 53 * 54 * It also provides support for polling connectors with a work item and for 55 * generic hotplug interrupt handling where the driver doesn't or cannot keep 56 * track of a per-connector hpd interrupt. 57 * 58 * This helper library can be used independently of the modeset helper library. 59 * Drivers can also overwrite different parts e.g. use their own hotplug 60 * handling code to avoid probing unrelated outputs. 61 */ 62 63 static bool drm_kms_helper_poll = true; 64 module_param_named(poll, drm_kms_helper_poll, bool, 0600); 65 66 static enum drm_mode_status 67 drm_mode_validate_flag(const struct drm_display_mode *mode, 68 int flags) 69 { 70 if ((mode->flags & DRM_MODE_FLAG_INTERLACE) && 71 !(flags & DRM_MODE_FLAG_INTERLACE)) 72 return MODE_NO_INTERLACE; 73 74 if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) && 75 !(flags & DRM_MODE_FLAG_DBLSCAN)) 76 return MODE_NO_DBLESCAN; 77 78 if ((mode->flags & DRM_MODE_FLAG_3D_MASK) && 79 !(flags & DRM_MODE_FLAG_3D_MASK)) 80 return MODE_NO_STEREO; 81 82 return MODE_OK; 83 } 84 85 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector) 86 { 87 struct drm_display_mode *mode; 88 89 if (!connector->cmdline_mode.specified) 90 return 0; 91 92 mode = drm_mode_create_from_cmdline_mode(connector->dev, 93 &connector->cmdline_mode); 94 if (mode == NULL) 95 return 0; 96 97 drm_mode_probed_add(connector, mode); 98 return 1; 99 } 100 101 #define DRM_OUTPUT_POLL_PERIOD (10*HZ) 102 /** 103 * drm_kms_helper_poll_enable_locked - re-enable output polling. 104 * @dev: drm_device 105 * 106 * This function re-enables the output polling work without 107 * locking the mode_config mutex. 108 * 109 * This is like drm_kms_helper_poll_enable() however it is to be 110 * called from a context where the mode_config mutex is locked 111 * already. 112 */ 113 void drm_kms_helper_poll_enable_locked(struct drm_device *dev) 114 { 115 bool poll = false; 116 struct drm_connector *connector; 117 118 WARN_ON(!mutex_is_locked(&dev->mode_config.mutex)); 119 120 if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll) 121 return; 122 123 drm_for_each_connector(connector, dev) { 124 if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT | 125 DRM_CONNECTOR_POLL_DISCONNECT)) 126 poll = true; 127 } 128 129 if (poll) 130 schedule_delayed_work(&dev->mode_config.output_poll_work, DRM_OUTPUT_POLL_PERIOD); 131 } 132 EXPORT_SYMBOL(drm_kms_helper_poll_enable_locked); 133 134 135 static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connector *connector, 136 uint32_t maxX, uint32_t maxY, bool merge_type_bits) 137 { 138 struct drm_device *dev = connector->dev; 139 struct drm_display_mode *mode; 140 const struct drm_connector_helper_funcs *connector_funcs = 141 connector->helper_private; 142 int count = 0; 143 int mode_flags = 0; 144 bool verbose_prune = true; 145 enum drm_connector_status old_status; 146 147 WARN_ON(!mutex_is_locked(&dev->mode_config.mutex)); 148 149 DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id, 150 connector->name); 151 /* set all modes to the unverified state */ 152 list_for_each_entry(mode, &connector->modes, head) 153 mode->status = MODE_UNVERIFIED; 154 155 if (connector->force) { 156 if (connector->force == DRM_FORCE_ON || 157 connector->force == DRM_FORCE_ON_DIGITAL) 158 connector->status = connector_status_connected; 159 else 160 connector->status = connector_status_disconnected; 161 if (connector->funcs->force) 162 connector->funcs->force(connector); 163 } else { 164 old_status = connector->status; 165 166 connector->status = connector->funcs->detect(connector, true); 167 168 /* 169 * Normally either the driver's hpd code or the poll loop should 170 * pick up any changes and fire the hotplug event. But if 171 * userspace sneaks in a probe, we might miss a change. Hence 172 * check here, and if anything changed start the hotplug code. 173 */ 174 if (old_status != connector->status) { 175 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n", 176 connector->base.id, 177 connector->name, 178 old_status, connector->status); 179 180 /* 181 * The hotplug event code might call into the fb 182 * helpers, and so expects that we do not hold any 183 * locks. Fire up the poll struct instead, it will 184 * disable itself again. 185 */ 186 dev->mode_config.delayed_event = true; 187 if (dev->mode_config.poll_enabled) 188 schedule_delayed_work(&dev->mode_config.output_poll_work, 189 0); 190 } 191 } 192 193 /* Re-enable polling in case the global poll config changed. */ 194 if (drm_kms_helper_poll != dev->mode_config.poll_running) 195 drm_kms_helper_poll_enable_locked(dev); 196 197 dev->mode_config.poll_running = drm_kms_helper_poll; 198 199 if (connector->status == connector_status_disconnected) { 200 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n", 201 connector->base.id, connector->name); 202 drm_mode_connector_update_edid_property(connector, NULL); 203 verbose_prune = false; 204 goto prune; 205 } 206 207 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE 208 count = drm_load_edid_firmware(connector); 209 if (count == 0) 210 #endif 211 { 212 if (connector->override_edid) { 213 struct edid *edid = (struct edid *) connector->edid_blob_ptr->data; 214 215 count = drm_add_edid_modes(connector, edid); 216 drm_edid_to_eld(connector, edid); 217 } else 218 count = (*connector_funcs->get_modes)(connector); 219 } 220 221 if (count == 0 && connector->status == connector_status_connected) 222 count = drm_add_modes_noedid(connector, 1024, 768); 223 count += drm_helper_probe_add_cmdline_mode(connector); 224 if (count == 0) 225 goto prune; 226 227 drm_mode_connector_list_update(connector, merge_type_bits); 228 229 if (connector->interlace_allowed) 230 mode_flags |= DRM_MODE_FLAG_INTERLACE; 231 if (connector->doublescan_allowed) 232 mode_flags |= DRM_MODE_FLAG_DBLSCAN; 233 if (connector->stereo_allowed) 234 mode_flags |= DRM_MODE_FLAG_3D_MASK; 235 236 list_for_each_entry(mode, &connector->modes, head) { 237 if (mode->status == MODE_OK) 238 mode->status = drm_mode_validate_basic(mode); 239 240 if (mode->status == MODE_OK) 241 mode->status = drm_mode_validate_size(mode, maxX, maxY); 242 243 if (mode->status == MODE_OK) 244 mode->status = drm_mode_validate_flag(mode, mode_flags); 245 246 if (mode->status == MODE_OK && connector_funcs->mode_valid) 247 mode->status = connector_funcs->mode_valid(connector, 248 mode); 249 } 250 251 prune: 252 drm_mode_prune_invalid(dev, &connector->modes, verbose_prune); 253 254 if (list_empty(&connector->modes)) 255 return 0; 256 257 list_for_each_entry(mode, &connector->modes, head) 258 mode->vrefresh = drm_mode_vrefresh(mode); 259 260 drm_mode_sort(&connector->modes); 261 262 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id, 263 connector->name); 264 list_for_each_entry(mode, &connector->modes, head) { 265 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V); 266 drm_mode_debug_printmodeline(mode); 267 } 268 269 return count; 270 } 271 272 /** 273 * drm_helper_probe_single_connector_modes - get complete set of display modes 274 * @connector: connector to probe 275 * @maxX: max width for modes 276 * @maxY: max height for modes 277 * 278 * Based on the helper callbacks implemented by @connector try to detect all 279 * valid modes. Modes will first be added to the connector's probed_modes list, 280 * then culled (based on validity and the @maxX, @maxY parameters) and put into 281 * the normal modes list. 282 * 283 * Intended to be use as a generic implementation of the ->fill_modes() 284 * @connector vfunc for drivers that use the crtc helpers for output mode 285 * filtering and detection. 286 * 287 * Returns: 288 * The number of modes found on @connector. 289 */ 290 int drm_helper_probe_single_connector_modes(struct drm_connector *connector, 291 uint32_t maxX, uint32_t maxY) 292 { 293 return drm_helper_probe_single_connector_modes_merge_bits(connector, maxX, maxY, true); 294 } 295 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes); 296 297 /** 298 * drm_helper_probe_single_connector_modes_nomerge - get complete set of display modes 299 * @connector: connector to probe 300 * @maxX: max width for modes 301 * @maxY: max height for modes 302 * 303 * This operates like drm_hehlper_probe_single_connector_modes except it 304 * replaces the mode bits instead of merging them for preferred modes. 305 */ 306 int drm_helper_probe_single_connector_modes_nomerge(struct drm_connector *connector, 307 uint32_t maxX, uint32_t maxY) 308 { 309 return drm_helper_probe_single_connector_modes_merge_bits(connector, maxX, maxY, false); 310 } 311 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes_nomerge); 312 313 /** 314 * drm_kms_helper_hotplug_event - fire off KMS hotplug events 315 * @dev: drm_device whose connector state changed 316 * 317 * This function fires off the uevent for userspace and also calls the 318 * output_poll_changed function, which is most commonly used to inform the fbdev 319 * emulation code and allow it to update the fbcon output configuration. 320 * 321 * Drivers should call this from their hotplug handling code when a change is 322 * detected. Note that this function does not do any output detection of its 323 * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the 324 * driver already. 325 * 326 * This function must be called from process context with no mode 327 * setting locks held. 328 */ 329 void drm_kms_helper_hotplug_event(struct drm_device *dev) 330 { 331 /* send a uevent + call fbdev */ 332 drm_sysfs_hotplug_event(dev); 333 if (dev->mode_config.funcs->output_poll_changed) 334 dev->mode_config.funcs->output_poll_changed(dev); 335 } 336 EXPORT_SYMBOL(drm_kms_helper_hotplug_event); 337 338 static void output_poll_execute(struct work_struct *work) 339 { 340 struct delayed_work *delayed_work = to_delayed_work(work); 341 struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work); 342 struct drm_connector *connector; 343 enum drm_connector_status old_status; 344 bool repoll = false, changed; 345 346 /* Pick up any changes detected by the probe functions. */ 347 changed = dev->mode_config.delayed_event; 348 dev->mode_config.delayed_event = false; 349 350 if (!drm_kms_helper_poll) 351 goto out; 352 353 mutex_lock(&dev->mode_config.mutex); 354 drm_for_each_connector(connector, dev) { 355 356 /* Ignore forced connectors. */ 357 if (connector->force) 358 continue; 359 360 /* Ignore HPD capable connectors and connectors where we don't 361 * want any hotplug detection at all for polling. */ 362 if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD) 363 continue; 364 365 old_status = connector->status; 366 /* if we are connected and don't want to poll for disconnect 367 skip it */ 368 if (old_status == connector_status_connected && 369 !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT)) 370 continue; 371 372 repoll = true; 373 374 connector->status = connector->funcs->detect(connector, false); 375 if (old_status != connector->status) { 376 const char *old, *new; 377 378 /* 379 * The poll work sets force=false when calling detect so 380 * that drivers can avoid to do disruptive tests (e.g. 381 * when load detect cycles could cause flickering on 382 * other, running displays). This bears the risk that we 383 * flip-flop between unknown here in the poll work and 384 * the real state when userspace forces a full detect 385 * call after receiving a hotplug event due to this 386 * change. 387 * 388 * Hence clamp an unknown detect status to the old 389 * value. 390 */ 391 if (connector->status == connector_status_unknown) { 392 connector->status = old_status; 393 continue; 394 } 395 396 old = drm_get_connector_status_name(old_status); 397 new = drm_get_connector_status_name(connector->status); 398 399 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] " 400 "status updated from %s to %s\n", 401 connector->base.id, 402 connector->name, 403 old, new); 404 405 changed = true; 406 } 407 } 408 409 mutex_unlock(&dev->mode_config.mutex); 410 411 out: 412 if (changed) 413 drm_kms_helper_hotplug_event(dev); 414 415 if (repoll) 416 schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD); 417 } 418 419 /** 420 * drm_kms_helper_is_poll_worker - is %current task an output poll worker? 421 * 422 * Determine if %current task is an output poll worker. This can be used 423 * to select distinct code paths for output polling versus other contexts. 424 * 425 * One use case is to avoid a deadlock between the output poll worker and 426 * the autosuspend worker wherein the latter waits for polling to finish 427 * upon calling drm_kms_helper_poll_disable(), while the former waits for 428 * runtime suspend to finish upon calling pm_runtime_get_sync() in a 429 * connector ->detect hook. 430 */ 431 bool drm_kms_helper_is_poll_worker(void) 432 { 433 struct work_struct *work = current_work(); 434 435 return work && work->func == output_poll_execute; 436 } 437 EXPORT_SYMBOL(drm_kms_helper_is_poll_worker); 438 439 /** 440 * drm_kms_helper_poll_disable - disable output polling 441 * @dev: drm_device 442 * 443 * This function disables the output polling work. 444 * 445 * Drivers can call this helper from their device suspend implementation. It is 446 * not an error to call this even when output polling isn't enabled or arlready 447 * disabled. 448 */ 449 void drm_kms_helper_poll_disable(struct drm_device *dev) 450 { 451 if (!dev->mode_config.poll_enabled) 452 return; 453 cancel_delayed_work_sync(&dev->mode_config.output_poll_work); 454 } 455 EXPORT_SYMBOL(drm_kms_helper_poll_disable); 456 457 /** 458 * drm_kms_helper_poll_enable - re-enable output polling. 459 * @dev: drm_device 460 * 461 * This function re-enables the output polling work. 462 * 463 * Drivers can call this helper from their device resume implementation. It is 464 * an error to call this when the output polling support has not yet been set 465 * up. 466 */ 467 void drm_kms_helper_poll_enable(struct drm_device *dev) 468 { 469 mutex_lock(&dev->mode_config.mutex); 470 drm_kms_helper_poll_enable_locked(dev); 471 mutex_unlock(&dev->mode_config.mutex); 472 } 473 EXPORT_SYMBOL(drm_kms_helper_poll_enable); 474 475 /** 476 * drm_kms_helper_poll_init - initialize and enable output polling 477 * @dev: drm_device 478 * 479 * This function intializes and then also enables output polling support for 480 * @dev. Drivers which do not have reliable hotplug support in hardware can use 481 * this helper infrastructure to regularly poll such connectors for changes in 482 * their connection state. 483 * 484 * Drivers can control which connectors are polled by setting the 485 * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On 486 * connectors where probing live outputs can result in visual distortion drivers 487 * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this. 488 * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are 489 * completely ignored by the polling logic. 490 * 491 * Note that a connector can be both polled and probed from the hotplug handler, 492 * in case the hotplug interrupt is known to be unreliable. 493 */ 494 void drm_kms_helper_poll_init(struct drm_device *dev) 495 { 496 INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute); 497 dev->mode_config.poll_enabled = true; 498 499 drm_kms_helper_poll_enable(dev); 500 } 501 EXPORT_SYMBOL(drm_kms_helper_poll_init); 502 503 /** 504 * drm_kms_helper_poll_fini - disable output polling and clean it up 505 * @dev: drm_device 506 */ 507 void drm_kms_helper_poll_fini(struct drm_device *dev) 508 { 509 drm_kms_helper_poll_disable(dev); 510 } 511 EXPORT_SYMBOL(drm_kms_helper_poll_fini); 512 513 /** 514 * drm_helper_hpd_irq_event - hotplug processing 515 * @dev: drm_device 516 * 517 * Drivers can use this helper function to run a detect cycle on all connectors 518 * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All 519 * other connectors are ignored, which is useful to avoid reprobing fixed 520 * panels. 521 * 522 * This helper function is useful for drivers which can't or don't track hotplug 523 * interrupts for each connector. 524 * 525 * Drivers which support hotplug interrupts for each connector individually and 526 * which have a more fine-grained detect logic should bypass this code and 527 * directly call drm_kms_helper_hotplug_event() in case the connector state 528 * changed. 529 * 530 * This function must be called from process context with no mode 531 * setting locks held. 532 * 533 * Note that a connector can be both polled and probed from the hotplug handler, 534 * in case the hotplug interrupt is known to be unreliable. 535 */ 536 bool drm_helper_hpd_irq_event(struct drm_device *dev) 537 { 538 struct drm_connector *connector; 539 enum drm_connector_status old_status; 540 bool changed = false; 541 542 if (!dev->mode_config.poll_enabled) 543 return false; 544 545 mutex_lock(&dev->mode_config.mutex); 546 drm_for_each_connector(connector, dev) { 547 548 /* Only handle HPD capable connectors. */ 549 if (!(connector->polled & DRM_CONNECTOR_POLL_HPD)) 550 continue; 551 552 old_status = connector->status; 553 554 connector->status = connector->funcs->detect(connector, false); 555 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n", 556 connector->base.id, 557 connector->name, 558 drm_get_connector_status_name(old_status), 559 drm_get_connector_status_name(connector->status)); 560 if (old_status != connector->status) 561 changed = true; 562 } 563 564 mutex_unlock(&dev->mode_config.mutex); 565 566 if (changed) 567 drm_kms_helper_hotplug_event(dev); 568 569 return changed; 570 } 571 EXPORT_SYMBOL(drm_helper_hpd_irq_event); 572