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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
67static bool drm_kms_helper_poll = true;
68module_param_named(poll, drm_kms_helper_poll, bool, 0600);
69
70static enum drm_mode_status
71drm_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
89static int
90drm_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
145static 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
180enum 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
191enum 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
203int
204drm_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 */
242void 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}
278EXPORT_SYMBOL(drm_kms_helper_poll_enable);
279
280static enum drm_connector_status
281drm_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
289retry:
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 */
327int
328drm_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}
355EXPORT_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 */
416int 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
436retry:
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
569prune:
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}
589EXPORT_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 */
607void 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}
616EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
617
618static 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
700out:
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 */
720bool 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}
726EXPORT_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 */
742void 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}
748EXPORT_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 */
769void 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}
776EXPORT_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 */
782void 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}
790EXPORT_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 */
815bool 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}
871EXPORT_SYMBOL(drm_helper_hpd_irq_event);