1 /* $NetBSD: drm_probe_helper.c,v 1.6 2021/12/18 23:44:57 riastradh 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 1.6 2021/12/18 23:44:57 riastradh Exp $");
36
37 #include <linux/export.h>
38 #include <linux/moduleparam.h>
39
40 #include <drm/drm_bridge.h>
41 #include <drm/drm_client.h>
42 #include <drm/drm_crtc.h>
43 #include <drm/drm_edid.h>
44 #include <drm/drm_fb_helper.h>
45 #include <drm/drm_fourcc.h>
46 #include <drm/drm_modeset_helper_vtables.h>
47 #include <drm/drm_print.h>
48 #include <drm/drm_probe_helper.h>
49 #include <drm/drm_sysfs.h>
50
51 #include "drm_crtc_helper_internal.h"
52
53 /**
54 * DOC: output probing helper overview
55 *
56 * This library provides some helper code for output probing. It provides an
57 * implementation of the core &drm_connector_funcs.fill_modes interface with
58 * drm_helper_probe_single_connector_modes().
59 *
60 * It also provides support for polling connectors with a work item and for
61 * generic hotplug interrupt handling where the driver doesn't or cannot keep
62 * track of a per-connector hpd interrupt.
63 *
64 * This helper library can be used independently of the modeset helper library.
65 * Drivers can also overwrite different parts e.g. use their own hotplug
66 * handling code to avoid probing unrelated outputs.
67 *
68 * The probe helpers share the function table structures with other display
69 * helper libraries. See &struct drm_connector_helper_funcs for the details.
70 */
71
72 static bool drm_kms_helper_poll = true;
73 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
74
75 static enum drm_mode_status
drm_mode_validate_flag(const struct drm_display_mode * mode,int flags)76 drm_mode_validate_flag(const struct drm_display_mode *mode,
77 int flags)
78 {
79 if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
80 !(flags & DRM_MODE_FLAG_INTERLACE))
81 return MODE_NO_INTERLACE;
82
83 if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
84 !(flags & DRM_MODE_FLAG_DBLSCAN))
85 return MODE_NO_DBLESCAN;
86
87 if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
88 !(flags & DRM_MODE_FLAG_3D_MASK))
89 return MODE_NO_STEREO;
90
91 return MODE_OK;
92 }
93
94 static enum drm_mode_status
drm_mode_validate_pipeline(struct drm_display_mode * mode,struct drm_connector * connector)95 drm_mode_validate_pipeline(struct drm_display_mode *mode,
96 struct drm_connector *connector)
97 {
98 struct drm_device *dev = connector->dev;
99 enum drm_mode_status ret = MODE_OK;
100 struct drm_encoder *encoder;
101
102 /* Step 1: Validate against connector */
103 ret = drm_connector_mode_valid(connector, mode);
104 if (ret != MODE_OK)
105 return ret;
106
107 /* Step 2: Validate against encoders and crtcs */
108 drm_connector_for_each_possible_encoder(connector, encoder) {
109 struct drm_bridge *bridge;
110 struct drm_crtc *crtc;
111
112 ret = drm_encoder_mode_valid(encoder, mode);
113 if (ret != MODE_OK) {
114 /* No point in continuing for crtc check as this encoder
115 * will not accept the mode anyway. If all encoders
116 * reject the mode then, at exit, ret will not be
117 * MODE_OK. */
118 continue;
119 }
120
121 bridge = drm_bridge_chain_get_first_bridge(encoder);
122 ret = drm_bridge_chain_mode_valid(bridge, mode);
123 if (ret != MODE_OK) {
124 /* There is also no point in continuing for crtc check
125 * here. */
126 continue;
127 }
128
129 drm_for_each_crtc(crtc, dev) {
130 if (!drm_encoder_crtc_ok(encoder, crtc))
131 continue;
132
133 ret = drm_crtc_mode_valid(crtc, mode);
134 if (ret == MODE_OK) {
135 /* If we get to this point there is at least
136 * one combination of encoder+crtc that works
137 * for this mode. Lets return now. */
138 return ret;
139 }
140 }
141 }
142
143 return ret;
144 }
145
drm_helper_probe_add_cmdline_mode(struct drm_connector * connector)146 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
147 {
148 struct drm_cmdline_mode *cmdline_mode;
149 struct drm_display_mode *mode;
150
151 cmdline_mode = &connector->cmdline_mode;
152 if (!cmdline_mode->specified)
153 return 0;
154
155 /* Only add a GTF mode if we find no matching probed modes */
156 list_for_each_entry(mode, &connector->probed_modes, head) {
157 if (mode->hdisplay != cmdline_mode->xres ||
158 mode->vdisplay != cmdline_mode->yres)
159 continue;
160
161 if (cmdline_mode->refresh_specified) {
162 /* The probed mode's vrefresh is set until later */
163 if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
164 continue;
165 }
166
167 return 0;
168 }
169
170 mode = drm_mode_create_from_cmdline_mode(connector->dev,
171 cmdline_mode);
172 if (mode == NULL)
173 return 0;
174
175 drm_mode_probed_add(connector, mode);
176 return 1;
177 }
178
drm_crtc_mode_valid(struct drm_crtc * crtc,const struct drm_display_mode * mode)179 enum drm_mode_status drm_crtc_mode_valid(struct drm_crtc *crtc,
180 const struct drm_display_mode *mode)
181 {
182 const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
183
184 if (!crtc_funcs || !crtc_funcs->mode_valid)
185 return MODE_OK;
186
187 return crtc_funcs->mode_valid(crtc, mode);
188 }
189
drm_encoder_mode_valid(struct drm_encoder * encoder,const struct drm_display_mode * mode)190 enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder,
191 const struct drm_display_mode *mode)
192 {
193 const struct drm_encoder_helper_funcs *encoder_funcs =
194 encoder->helper_private;
195
196 if (!encoder_funcs || !encoder_funcs->mode_valid)
197 return MODE_OK;
198
199 return encoder_funcs->mode_valid(encoder, mode);
200 }
201
drm_connector_mode_valid(struct drm_connector * connector,struct drm_display_mode * mode)202 enum drm_mode_status drm_connector_mode_valid(struct drm_connector *connector,
203 struct drm_display_mode *mode)
204 {
205 const struct drm_connector_helper_funcs *connector_funcs =
206 connector->helper_private;
207
208 if (!connector_funcs || !connector_funcs->mode_valid)
209 return MODE_OK;
210
211 return connector_funcs->mode_valid(connector, mode);
212 }
213
214 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
215 /**
216 * drm_kms_helper_poll_enable - re-enable output polling.
217 * @dev: drm_device
218 *
219 * This function re-enables the output polling work, after it has been
220 * temporarily disabled using drm_kms_helper_poll_disable(), for example over
221 * suspend/resume.
222 *
223 * Drivers can call this helper from their device resume implementation. It is
224 * not an error to call this even when output polling isn't enabled.
225 *
226 * Note that calls to enable and disable polling must be strictly ordered, which
227 * is automatically the case when they're only call from suspend/resume
228 * callbacks.
229 */
drm_kms_helper_poll_enable(struct drm_device * dev)230 void drm_kms_helper_poll_enable(struct drm_device *dev)
231 {
232 bool poll = false;
233 struct drm_connector *connector;
234 struct drm_connector_list_iter conn_iter;
235 unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
236
237 if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
238 return;
239
240 drm_connector_list_iter_begin(dev, &conn_iter);
241 drm_for_each_connector_iter(connector, &conn_iter) {
242 if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
243 DRM_CONNECTOR_POLL_DISCONNECT))
244 poll = true;
245 }
246 drm_connector_list_iter_end(&conn_iter);
247
248 if (dev->mode_config.delayed_event) {
249 /*
250 * FIXME:
251 *
252 * Use short (1s) delay to handle the initial delayed event.
253 * This delay should not be needed, but Optimus/nouveau will
254 * fail in a mysterious way if the delayed event is handled as
255 * soon as possible like it is done in
256 * drm_helper_probe_single_connector_modes() in case the poll
257 * was enabled before.
258 */
259 poll = true;
260 delay = HZ;
261 }
262
263 if (poll)
264 schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
265 }
266 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
267
268 static enum drm_connector_status
drm_helper_probe_detect_ctx(struct drm_connector * connector,bool force)269 drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
270 {
271 const struct drm_connector_helper_funcs *funcs = connector->helper_private;
272 struct drm_modeset_acquire_ctx ctx;
273 int ret;
274
275 drm_modeset_acquire_init(&ctx, 0);
276
277 retry:
278 ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
279 if (!ret) {
280 if (funcs->detect_ctx)
281 ret = funcs->detect_ctx(connector, &ctx, force);
282 else if (connector->funcs->detect)
283 ret = connector->funcs->detect(connector, force);
284 else
285 ret = connector_status_connected;
286 }
287
288 if (ret == -EDEADLK) {
289 drm_modeset_backoff(&ctx);
290 goto retry;
291 }
292
293 if (WARN_ON(ret < 0))
294 ret = connector_status_unknown;
295
296 drm_modeset_drop_locks(&ctx);
297 drm_modeset_acquire_fini(&ctx);
298
299 return ret;
300 }
301
302 /**
303 * drm_helper_probe_detect - probe connector status
304 * @connector: connector to probe
305 * @ctx: acquire_ctx, or NULL to let this function handle locking.
306 * @force: Whether destructive probe operations should be performed.
307 *
308 * This function calls the detect callbacks of the connector.
309 * This function returns &drm_connector_status, or
310 * if @ctx is set, it might also return -EDEADLK.
311 */
312 int
drm_helper_probe_detect(struct drm_connector * connector,struct drm_modeset_acquire_ctx * ctx,bool force)313 drm_helper_probe_detect(struct drm_connector *connector,
314 struct drm_modeset_acquire_ctx *ctx,
315 bool force)
316 {
317 const struct drm_connector_helper_funcs *funcs = connector->helper_private;
318 struct drm_device *dev = connector->dev;
319 int ret;
320
321 if (!ctx)
322 return drm_helper_probe_detect_ctx(connector, force);
323
324 ret = drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
325 if (ret)
326 return ret;
327
328 if (funcs->detect_ctx)
329 return funcs->detect_ctx(connector, ctx, force);
330 else if (connector->funcs->detect)
331 return connector->funcs->detect(connector, force);
332 else
333 return connector_status_connected;
334 }
335 EXPORT_SYMBOL(drm_helper_probe_detect);
336
337 /**
338 * drm_helper_probe_single_connector_modes - get complete set of display modes
339 * @connector: connector to probe
340 * @maxX: max width for modes
341 * @maxY: max height for modes
342 *
343 * Based on the helper callbacks implemented by @connector in struct
344 * &drm_connector_helper_funcs try to detect all valid modes. Modes will first
345 * be added to the connector's probed_modes list, then culled (based on validity
346 * and the @maxX, @maxY parameters) and put into the normal modes list.
347 *
348 * Intended to be used as a generic implementation of the
349 * &drm_connector_funcs.fill_modes() vfunc for drivers that use the CRTC helpers
350 * for output mode filtering and detection.
351 *
352 * The basic procedure is as follows
353 *
354 * 1. All modes currently on the connector's modes list are marked as stale
355 *
356 * 2. New modes are added to the connector's probed_modes list with
357 * drm_mode_probed_add(). New modes start their life with status as OK.
358 * Modes are added from a single source using the following priority order.
359 *
360 * - &drm_connector_helper_funcs.get_modes vfunc
361 * - if the connector status is connector_status_connected, standard
362 * VESA DMT modes up to 1024x768 are automatically added
363 * (drm_add_modes_noedid())
364 *
365 * Finally modes specified via the kernel command line (video=...) are
366 * added in addition to what the earlier probes produced
367 * (drm_helper_probe_add_cmdline_mode()). These modes are generated
368 * using the VESA GTF/CVT formulas.
369 *
370 * 3. Modes are moved from the probed_modes list to the modes list. Potential
371 * duplicates are merged together (see drm_connector_list_update()).
372 * After this step the probed_modes list will be empty again.
373 *
374 * 4. Any non-stale mode on the modes list then undergoes validation
375 *
376 * - drm_mode_validate_basic() performs basic sanity checks
377 * - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
378 * (if specified)
379 * - drm_mode_validate_flag() checks the modes against basic connector
380 * capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
381 * - the optional &drm_connector_helper_funcs.mode_valid helper can perform
382 * driver and/or sink specific checks
383 * - the optional &drm_crtc_helper_funcs.mode_valid,
384 * &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid
385 * helpers can perform driver and/or source specific checks which are also
386 * enforced by the modeset/atomic helpers
387 *
388 * 5. Any mode whose status is not OK is pruned from the connector's modes list,
389 * accompanied by a debug message indicating the reason for the mode's
390 * rejection (see drm_mode_prune_invalid()).
391 *
392 * Returns:
393 * The number of modes found on @connector.
394 */
drm_helper_probe_single_connector_modes(struct drm_connector * connector,uint32_t maxX,uint32_t maxY)395 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
396 uint32_t maxX, uint32_t maxY)
397 {
398 struct drm_device *dev = connector->dev;
399 struct drm_display_mode *mode;
400 const struct drm_connector_helper_funcs *connector_funcs =
401 connector->helper_private;
402 int count = 0, ret;
403 int mode_flags = 0;
404 bool verbose_prune = true;
405 enum drm_connector_status old_status;
406 struct drm_modeset_acquire_ctx ctx;
407
408 WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
409
410 drm_modeset_acquire_init(&ctx, 0);
411
412 DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
413 connector->name);
414
415 retry:
416 ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
417 if (ret == -EDEADLK) {
418 drm_modeset_backoff(&ctx);
419 goto retry;
420 } else
421 WARN_ON(ret < 0);
422
423 /* set all old modes to the stale state */
424 list_for_each_entry(mode, &connector->modes, head)
425 mode->status = MODE_STALE;
426
427 old_status = connector->status;
428
429 if (connector->force) {
430 if (connector->force == DRM_FORCE_ON ||
431 connector->force == DRM_FORCE_ON_DIGITAL)
432 connector->status = connector_status_connected;
433 else
434 connector->status = connector_status_disconnected;
435 if (connector->funcs->force)
436 connector->funcs->force(connector);
437 } else {
438 ret = drm_helper_probe_detect(connector, &ctx, true);
439
440 if (ret == -EDEADLK) {
441 drm_modeset_backoff(&ctx);
442 goto retry;
443 } else if (WARN(ret < 0, "Invalid return value %i for connector detection\n", ret))
444 ret = connector_status_unknown;
445
446 connector->status = ret;
447 }
448
449 /*
450 * Normally either the driver's hpd code or the poll loop should
451 * pick up any changes and fire the hotplug event. But if
452 * userspace sneaks in a probe, we might miss a change. Hence
453 * check here, and if anything changed start the hotplug code.
454 */
455 if (old_status != connector->status) {
456 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
457 connector->base.id,
458 connector->name,
459 drm_get_connector_status_name(old_status),
460 drm_get_connector_status_name(connector->status));
461
462 /*
463 * The hotplug event code might call into the fb
464 * helpers, and so expects that we do not hold any
465 * locks. Fire up the poll struct instead, it will
466 * disable itself again.
467 */
468 dev->mode_config.delayed_event = true;
469 if (dev->mode_config.poll_enabled)
470 schedule_delayed_work(&dev->mode_config.output_poll_work,
471 0);
472 }
473
474 /* Re-enable polling in case the global poll config changed. */
475 if (drm_kms_helper_poll != dev->mode_config.poll_running)
476 drm_kms_helper_poll_enable(dev);
477
478 dev->mode_config.poll_running = drm_kms_helper_poll;
479
480 if (connector->status == connector_status_disconnected) {
481 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
482 connector->base.id, connector->name);
483 drm_connector_update_edid_property(connector, NULL);
484 verbose_prune = false;
485 goto prune;
486 }
487
488 count = (*connector_funcs->get_modes)(connector);
489
490 /*
491 * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
492 * override/firmware EDID.
493 */
494 if (count == 0 && connector->status == connector_status_connected)
495 count = drm_add_override_edid_modes(connector);
496
497 if (count == 0 && connector->status == connector_status_connected)
498 count = drm_add_modes_noedid(connector, 1024, 768);
499 count += drm_helper_probe_add_cmdline_mode(connector);
500 if (count == 0)
501 goto prune;
502
503 drm_connector_list_update(connector);
504
505 if (connector->interlace_allowed)
506 mode_flags |= DRM_MODE_FLAG_INTERLACE;
507 if (connector->doublescan_allowed)
508 mode_flags |= DRM_MODE_FLAG_DBLSCAN;
509 if (connector->stereo_allowed)
510 mode_flags |= DRM_MODE_FLAG_3D_MASK;
511
512 list_for_each_entry(mode, &connector->modes, head) {
513 if (mode->status == MODE_OK)
514 mode->status = drm_mode_validate_driver(dev, mode);
515
516 if (mode->status == MODE_OK)
517 mode->status = drm_mode_validate_size(mode, maxX, maxY);
518
519 if (mode->status == MODE_OK)
520 mode->status = drm_mode_validate_flag(mode, mode_flags);
521
522 if (mode->status == MODE_OK)
523 mode->status = drm_mode_validate_pipeline(mode,
524 connector);
525
526 if (mode->status == MODE_OK)
527 mode->status = drm_mode_validate_ycbcr420(mode,
528 connector);
529 }
530
531 prune:
532 drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
533
534 drm_modeset_drop_locks(&ctx);
535 drm_modeset_acquire_fini(&ctx);
536
537 if (list_empty(&connector->modes))
538 return 0;
539
540 list_for_each_entry(mode, &connector->modes, head)
541 mode->vrefresh = drm_mode_vrefresh(mode);
542
543 drm_mode_sort(&connector->modes);
544
545 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
546 connector->name);
547 list_for_each_entry(mode, &connector->modes, head) {
548 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
549 drm_mode_debug_printmodeline(mode);
550 }
551
552 return count;
553 }
554 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
555
556 /**
557 * drm_kms_helper_hotplug_event - fire off KMS hotplug events
558 * @dev: drm_device whose connector state changed
559 *
560 * This function fires off the uevent for userspace and also calls the
561 * output_poll_changed function, which is most commonly used to inform the fbdev
562 * emulation code and allow it to update the fbcon output configuration.
563 *
564 * Drivers should call this from their hotplug handling code when a change is
565 * detected. Note that this function does not do any output detection of its
566 * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
567 * driver already.
568 *
569 * This function must be called from process context with no mode
570 * setting locks held.
571 */
drm_kms_helper_hotplug_event(struct drm_device * dev)572 void drm_kms_helper_hotplug_event(struct drm_device *dev)
573 {
574 #ifdef __NetBSD__
575 sysmon_pswitch_event(&dev->sc_monitor_hotplug, PSWITCH_EVENT_PRESSED);
576 #endif
577 /* send a uevent + call fbdev */
578 drm_sysfs_hotplug_event(dev);
579 if (dev->mode_config.funcs->output_poll_changed)
580 dev->mode_config.funcs->output_poll_changed(dev);
581
582 drm_client_dev_hotplug(dev);
583 }
584 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
585
output_poll_execute(struct work_struct * work)586 static void output_poll_execute(struct work_struct *work)
587 {
588 struct delayed_work *delayed_work = to_delayed_work(work);
589 struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
590 struct drm_connector *connector;
591 struct drm_connector_list_iter conn_iter;
592 enum drm_connector_status old_status;
593 bool repoll = false, changed;
594
595 if (!dev->mode_config.poll_enabled)
596 return;
597
598 /* Pick up any changes detected by the probe functions. */
599 changed = dev->mode_config.delayed_event;
600 dev->mode_config.delayed_event = false;
601
602 if (!drm_kms_helper_poll)
603 goto out;
604
605 if (!mutex_trylock(&dev->mode_config.mutex)) {
606 repoll = true;
607 goto out;
608 }
609
610 drm_connector_list_iter_begin(dev, &conn_iter);
611 drm_for_each_connector_iter(connector, &conn_iter) {
612 /* Ignore forced connectors. */
613 if (connector->force)
614 continue;
615
616 /* Ignore HPD capable connectors and connectors where we don't
617 * want any hotplug detection at all for polling. */
618 if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
619 continue;
620
621 old_status = connector->status;
622 /* if we are connected and don't want to poll for disconnect
623 skip it */
624 if (old_status == connector_status_connected &&
625 !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
626 continue;
627
628 repoll = true;
629
630 connector->status = drm_helper_probe_detect(connector, NULL, false);
631 if (old_status != connector->status) {
632 const char *old, *new;
633
634 /*
635 * The poll work sets force=false when calling detect so
636 * that drivers can avoid to do disruptive tests (e.g.
637 * when load detect cycles could cause flickering on
638 * other, running displays). This bears the risk that we
639 * flip-flop between unknown here in the poll work and
640 * the real state when userspace forces a full detect
641 * call after receiving a hotplug event due to this
642 * change.
643 *
644 * Hence clamp an unknown detect status to the old
645 * value.
646 */
647 if (connector->status == connector_status_unknown) {
648 connector->status = old_status;
649 continue;
650 }
651
652 old = drm_get_connector_status_name(old_status);
653 new = drm_get_connector_status_name(connector->status);
654
655 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
656 "status updated from %s to %s\n",
657 connector->base.id,
658 connector->name,
659 old, new);
660
661 changed = true;
662 }
663 }
664 drm_connector_list_iter_end(&conn_iter);
665
666 mutex_unlock(&dev->mode_config.mutex);
667
668 out:
669 if (changed)
670 drm_kms_helper_hotplug_event(dev);
671
672 if (repoll)
673 schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
674 }
675
676 /**
677 * drm_kms_helper_is_poll_worker - is %current task an output poll worker?
678 *
679 * Determine if %current task is an output poll worker. This can be used
680 * to select distinct code paths for output polling versus other contexts.
681 *
682 * One use case is to avoid a deadlock between the output poll worker and
683 * the autosuspend worker wherein the latter waits for polling to finish
684 * upon calling drm_kms_helper_poll_disable(), while the former waits for
685 * runtime suspend to finish upon calling pm_runtime_get_sync() in a
686 * connector ->detect hook.
687 */
drm_kms_helper_is_poll_worker(void)688 bool drm_kms_helper_is_poll_worker(void)
689 {
690 struct work_struct *work = current_work();
691
692 return work && work->func == output_poll_execute;
693 }
694 EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
695
696 /**
697 * drm_kms_helper_poll_disable - disable output polling
698 * @dev: drm_device
699 *
700 * This function disables the output polling work.
701 *
702 * Drivers can call this helper from their device suspend implementation. It is
703 * not an error to call this even when output polling isn't enabled or already
704 * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
705 *
706 * Note that calls to enable and disable polling must be strictly ordered, which
707 * is automatically the case when they're only call from suspend/resume
708 * callbacks.
709 */
drm_kms_helper_poll_disable(struct drm_device * dev)710 void drm_kms_helper_poll_disable(struct drm_device *dev)
711 {
712 if (!dev->mode_config.poll_enabled)
713 return;
714 cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
715 }
716 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
717
718 /**
719 * drm_kms_helper_poll_init - initialize and enable output polling
720 * @dev: drm_device
721 *
722 * This function intializes and then also enables output polling support for
723 * @dev. Drivers which do not have reliable hotplug support in hardware can use
724 * this helper infrastructure to regularly poll such connectors for changes in
725 * their connection state.
726 *
727 * Drivers can control which connectors are polled by setting the
728 * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
729 * connectors where probing live outputs can result in visual distortion drivers
730 * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
731 * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
732 * completely ignored by the polling logic.
733 *
734 * Note that a connector can be both polled and probed from the hotplug handler,
735 * in case the hotplug interrupt is known to be unreliable.
736 */
drm_kms_helper_poll_init(struct drm_device * dev)737 void drm_kms_helper_poll_init(struct drm_device *dev)
738 {
739 INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
740 dev->mode_config.poll_enabled = true;
741
742 drm_kms_helper_poll_enable(dev);
743 }
744 EXPORT_SYMBOL(drm_kms_helper_poll_init);
745
746 /**
747 * drm_kms_helper_poll_fini - disable output polling and clean it up
748 * @dev: drm_device
749 */
drm_kms_helper_poll_fini(struct drm_device * dev)750 void drm_kms_helper_poll_fini(struct drm_device *dev)
751 {
752 if (!dev->mode_config.poll_enabled)
753 return;
754
755 dev->mode_config.poll_enabled = false;
756 cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
757 }
758 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
759
760 /**
761 * drm_helper_hpd_irq_event - hotplug processing
762 * @dev: drm_device
763 *
764 * Drivers can use this helper function to run a detect cycle on all connectors
765 * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
766 * other connectors are ignored, which is useful to avoid reprobing fixed
767 * panels.
768 *
769 * This helper function is useful for drivers which can't or don't track hotplug
770 * interrupts for each connector.
771 *
772 * Drivers which support hotplug interrupts for each connector individually and
773 * which have a more fine-grained detect logic should bypass this code and
774 * directly call drm_kms_helper_hotplug_event() in case the connector state
775 * changed.
776 *
777 * This function must be called from process context with no mode
778 * setting locks held.
779 *
780 * Note that a connector can be both polled and probed from the hotplug handler,
781 * in case the hotplug interrupt is known to be unreliable.
782 */
drm_helper_hpd_irq_event(struct drm_device * dev)783 bool drm_helper_hpd_irq_event(struct drm_device *dev)
784 {
785 struct drm_connector *connector;
786 struct drm_connector_list_iter conn_iter;
787 enum drm_connector_status old_status;
788 bool changed = false;
789
790 if (!dev->mode_config.poll_enabled)
791 return false;
792
793 mutex_lock(&dev->mode_config.mutex);
794 drm_connector_list_iter_begin(dev, &conn_iter);
795 drm_for_each_connector_iter(connector, &conn_iter) {
796 /* Only handle HPD capable connectors. */
797 if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
798 continue;
799
800 old_status = connector->status;
801
802 connector->status = drm_helper_probe_detect(connector, NULL, false);
803 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
804 connector->base.id,
805 connector->name,
806 drm_get_connector_status_name(old_status),
807 drm_get_connector_status_name(connector->status));
808 if (old_status != connector->status)
809 changed = true;
810 }
811 drm_connector_list_iter_end(&conn_iter);
812 mutex_unlock(&dev->mode_config.mutex);
813
814 if (changed)
815 drm_kms_helper_hotplug_event(dev);
816
817 return changed;
818 }
819 EXPORT_SYMBOL(drm_helper_hpd_irq_event);
820