xref: /linux/drivers/gpu/drm/drm_probe_helper.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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/drmP.h>
36 #include <drm/drm_crtc.h>
37 #include <drm/drm_fourcc.h>
38 #include <drm/drm_crtc_helper.h>
39 #include <drm/drm_fb_helper.h>
40 #include <drm/drm_edid.h>
41 
42 /**
43  * DOC: output probing helper overview
44  *
45  * This library provides some helper code for output probing. It provides an
46  * implementation of the core &drm_connector_funcs.fill_modes interface with
47  * drm_helper_probe_single_connector_modes.
48  *
49  * It also provides support for polling connectors with a work item and for
50  * generic hotplug interrupt handling where the driver doesn't or cannot keep
51  * track of a per-connector hpd interrupt.
52  *
53  * This helper library can be used independently of the modeset helper library.
54  * Drivers can also overwrite different parts e.g. use their own hotplug
55  * handling code to avoid probing unrelated outputs.
56  *
57  * The probe helpers share the function table structures with other display
58  * helper libraries. See &struct drm_connector_helper_funcs for the details.
59  */
60 
61 static bool drm_kms_helper_poll = true;
62 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
63 
64 static enum drm_mode_status
65 drm_mode_validate_flag(const struct drm_display_mode *mode,
66 		       int flags)
67 {
68 	if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
69 	    !(flags & DRM_MODE_FLAG_INTERLACE))
70 		return MODE_NO_INTERLACE;
71 
72 	if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
73 	    !(flags & DRM_MODE_FLAG_DBLSCAN))
74 		return MODE_NO_DBLESCAN;
75 
76 	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
77 	    !(flags & DRM_MODE_FLAG_3D_MASK))
78 		return MODE_NO_STEREO;
79 
80 	return MODE_OK;
81 }
82 
83 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
84 {
85 	struct drm_cmdline_mode *cmdline_mode;
86 	struct drm_display_mode *mode;
87 
88 	cmdline_mode = &connector->cmdline_mode;
89 	if (!cmdline_mode->specified)
90 		return 0;
91 
92 	/* Only add a GTF mode if we find no matching probed modes */
93 	list_for_each_entry(mode, &connector->probed_modes, head) {
94 		if (mode->hdisplay != cmdline_mode->xres ||
95 		    mode->vdisplay != cmdline_mode->yres)
96 			continue;
97 
98 		if (cmdline_mode->refresh_specified) {
99 			/* The probed mode's vrefresh is set until later */
100 			if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
101 				continue;
102 		}
103 
104 		return 0;
105 	}
106 
107 	mode = drm_mode_create_from_cmdline_mode(connector->dev,
108 						 cmdline_mode);
109 	if (mode == NULL)
110 		return 0;
111 
112 	drm_mode_probed_add(connector, mode);
113 	return 1;
114 }
115 
116 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
117 /**
118  * drm_kms_helper_poll_enable - re-enable output polling.
119  * @dev: drm_device
120  *
121  * This function re-enables the output polling work, after it has been
122  * temporarily disabled using drm_kms_helper_poll_disable(), for example over
123  * suspend/resume.
124  *
125  * Drivers can call this helper from their device resume implementation. It is
126  * an error to call this when the output polling support has not yet been set
127  * up.
128  *
129  * Note that calls to enable and disable polling must be strictly ordered, which
130  * is automatically the case when they're only call from suspend/resume
131  * callbacks.
132  */
133 void drm_kms_helper_poll_enable(struct drm_device *dev)
134 {
135 	bool poll = false;
136 	struct drm_connector *connector;
137 	struct drm_connector_list_iter conn_iter;
138 	unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
139 
140 	if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
141 		return;
142 
143 	drm_connector_list_iter_get(dev, &conn_iter);
144 	drm_for_each_connector_iter(connector, &conn_iter) {
145 		if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
146 					 DRM_CONNECTOR_POLL_DISCONNECT))
147 			poll = true;
148 	}
149 	drm_connector_list_iter_put(&conn_iter);
150 
151 	if (dev->mode_config.delayed_event) {
152 		/*
153 		 * FIXME:
154 		 *
155 		 * Use short (1s) delay to handle the initial delayed event.
156 		 * This delay should not be needed, but Optimus/nouveau will
157 		 * fail in a mysterious way if the delayed event is handled as
158 		 * soon as possible like it is done in
159 		 * drm_helper_probe_single_connector_modes() in case the poll
160 		 * was enabled before.
161 		 */
162 		poll = true;
163 		delay = HZ;
164 	}
165 
166 	if (poll)
167 		schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
168 }
169 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
170 
171 static enum drm_connector_status
172 drm_connector_detect(struct drm_connector *connector, bool force)
173 {
174 	return connector->funcs->detect ?
175 		connector->funcs->detect(connector, force) :
176 		connector_status_connected;
177 }
178 
179 /**
180  * drm_helper_probe_single_connector_modes - get complete set of display modes
181  * @connector: connector to probe
182  * @maxX: max width for modes
183  * @maxY: max height for modes
184  *
185  * Based on the helper callbacks implemented by @connector in struct
186  * &drm_connector_helper_funcs try to detect all valid modes.  Modes will first
187  * be added to the connector's probed_modes list, then culled (based on validity
188  * and the @maxX, @maxY parameters) and put into the normal modes list.
189  *
190  * Intended to be used as a generic implementation of the
191  * &drm_connector_funcs.fill_modes() vfunc for drivers that use the CRTC helpers
192  * for output mode filtering and detection.
193  *
194  * The basic procedure is as follows
195  *
196  * 1. All modes currently on the connector's modes list are marked as stale
197  *
198  * 2. New modes are added to the connector's probed_modes list with
199  *    drm_mode_probed_add(). New modes start their life with status as OK.
200  *    Modes are added from a single source using the following priority order.
201  *
202  *    - debugfs 'override_edid' (used for testing only)
203  *    - firmware EDID (drm_load_edid_firmware())
204  *    - &drm_connector_helper_funcs.get_modes vfunc
205  *    - if the connector status is connector_status_connected, standard
206  *      VESA DMT modes up to 1024x768 are automatically added
207  *      (drm_add_modes_noedid())
208  *
209  *    Finally modes specified via the kernel command line (video=...) are
210  *    added in addition to what the earlier probes produced
211  *    (drm_helper_probe_add_cmdline_mode()). These modes are generated
212  *    using the VESA GTF/CVT formulas.
213  *
214  * 3. Modes are moved from the probed_modes list to the modes list. Potential
215  *    duplicates are merged together (see drm_mode_connector_list_update()).
216  *    After this step the probed_modes list will be empty again.
217  *
218  * 4. Any non-stale mode on the modes list then undergoes validation
219  *
220  *    - drm_mode_validate_basic() performs basic sanity checks
221  *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
222  *      (if specified)
223  *    - drm_mode_validate_flag() checks the modes against basic connector
224  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
225  *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
226  *      driver and/or hardware specific checks
227  *
228  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
229  *    accompanied by a debug message indicating the reason for the mode's
230  *    rejection (see drm_mode_prune_invalid()).
231  *
232  * Returns:
233  * The number of modes found on @connector.
234  */
235 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
236 					    uint32_t maxX, uint32_t maxY)
237 {
238 	struct drm_device *dev = connector->dev;
239 	struct drm_display_mode *mode;
240 	const struct drm_connector_helper_funcs *connector_funcs =
241 		connector->helper_private;
242 	int count = 0;
243 	int mode_flags = 0;
244 	bool verbose_prune = true;
245 	enum drm_connector_status old_status;
246 
247 	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
248 
249 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
250 			connector->name);
251 	/* set all old modes to the stale state */
252 	list_for_each_entry(mode, &connector->modes, head)
253 		mode->status = MODE_STALE;
254 
255 	old_status = connector->status;
256 
257 	if (connector->force) {
258 		if (connector->force == DRM_FORCE_ON ||
259 		    connector->force == DRM_FORCE_ON_DIGITAL)
260 			connector->status = connector_status_connected;
261 		else
262 			connector->status = connector_status_disconnected;
263 		if (connector->funcs->force)
264 			connector->funcs->force(connector);
265 	} else {
266 		connector->status = drm_connector_detect(connector, true);
267 	}
268 
269 	/*
270 	 * Normally either the driver's hpd code or the poll loop should
271 	 * pick up any changes and fire the hotplug event. But if
272 	 * userspace sneaks in a probe, we might miss a change. Hence
273 	 * check here, and if anything changed start the hotplug code.
274 	 */
275 	if (old_status != connector->status) {
276 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
277 			      connector->base.id,
278 			      connector->name,
279 			      drm_get_connector_status_name(old_status),
280 			      drm_get_connector_status_name(connector->status));
281 
282 		/*
283 		 * The hotplug event code might call into the fb
284 		 * helpers, and so expects that we do not hold any
285 		 * locks. Fire up the poll struct instead, it will
286 		 * disable itself again.
287 		 */
288 		dev->mode_config.delayed_event = true;
289 		if (dev->mode_config.poll_enabled)
290 			schedule_delayed_work(&dev->mode_config.output_poll_work,
291 					      0);
292 	}
293 
294 	/* Re-enable polling in case the global poll config changed. */
295 	if (drm_kms_helper_poll != dev->mode_config.poll_running)
296 		drm_kms_helper_poll_enable(dev);
297 
298 	dev->mode_config.poll_running = drm_kms_helper_poll;
299 
300 	if (connector->status == connector_status_disconnected) {
301 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
302 			connector->base.id, connector->name);
303 		drm_mode_connector_update_edid_property(connector, NULL);
304 		verbose_prune = false;
305 		goto prune;
306 	}
307 
308 	if (connector->override_edid) {
309 		struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
310 
311 		count = drm_add_edid_modes(connector, edid);
312 		drm_edid_to_eld(connector, edid);
313 	} else {
314 		count = drm_load_edid_firmware(connector);
315 		if (count == 0)
316 			count = (*connector_funcs->get_modes)(connector);
317 	}
318 
319 	if (count == 0 && connector->status == connector_status_connected)
320 		count = drm_add_modes_noedid(connector, 1024, 768);
321 	count += drm_helper_probe_add_cmdline_mode(connector);
322 	if (count == 0)
323 		goto prune;
324 
325 	drm_mode_connector_list_update(connector);
326 
327 	if (connector->interlace_allowed)
328 		mode_flags |= DRM_MODE_FLAG_INTERLACE;
329 	if (connector->doublescan_allowed)
330 		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
331 	if (connector->stereo_allowed)
332 		mode_flags |= DRM_MODE_FLAG_3D_MASK;
333 
334 	list_for_each_entry(mode, &connector->modes, head) {
335 		if (mode->status == MODE_OK)
336 			mode->status = drm_mode_validate_basic(mode);
337 
338 		if (mode->status == MODE_OK)
339 			mode->status = drm_mode_validate_size(mode, maxX, maxY);
340 
341 		if (mode->status == MODE_OK)
342 			mode->status = drm_mode_validate_flag(mode, mode_flags);
343 
344 		if (mode->status == MODE_OK && connector_funcs->mode_valid)
345 			mode->status = connector_funcs->mode_valid(connector,
346 								   mode);
347 	}
348 
349 prune:
350 	drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);
351 
352 	if (list_empty(&connector->modes))
353 		return 0;
354 
355 	list_for_each_entry(mode, &connector->modes, head)
356 		mode->vrefresh = drm_mode_vrefresh(mode);
357 
358 	drm_mode_sort(&connector->modes);
359 
360 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
361 			connector->name);
362 	list_for_each_entry(mode, &connector->modes, head) {
363 		drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
364 		drm_mode_debug_printmodeline(mode);
365 	}
366 
367 	return count;
368 }
369 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
370 
371 /**
372  * drm_kms_helper_hotplug_event - fire off KMS hotplug events
373  * @dev: drm_device whose connector state changed
374  *
375  * This function fires off the uevent for userspace and also calls the
376  * output_poll_changed function, which is most commonly used to inform the fbdev
377  * emulation code and allow it to update the fbcon output configuration.
378  *
379  * Drivers should call this from their hotplug handling code when a change is
380  * detected. Note that this function does not do any output detection of its
381  * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
382  * driver already.
383  *
384  * This function must be called from process context with no mode
385  * setting locks held.
386  */
387 void drm_kms_helper_hotplug_event(struct drm_device *dev)
388 {
389 	/* send a uevent + call fbdev */
390 	drm_sysfs_hotplug_event(dev);
391 	if (dev->mode_config.funcs->output_poll_changed)
392 		dev->mode_config.funcs->output_poll_changed(dev);
393 }
394 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
395 
396 static void output_poll_execute(struct work_struct *work)
397 {
398 	struct delayed_work *delayed_work = to_delayed_work(work);
399 	struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
400 	struct drm_connector *connector;
401 	struct drm_connector_list_iter conn_iter;
402 	enum drm_connector_status old_status;
403 	bool repoll = false, changed;
404 
405 	/* Pick up any changes detected by the probe functions. */
406 	changed = dev->mode_config.delayed_event;
407 	dev->mode_config.delayed_event = false;
408 
409 	if (!drm_kms_helper_poll)
410 		goto out;
411 
412 	if (!mutex_trylock(&dev->mode_config.mutex)) {
413 		repoll = true;
414 		goto out;
415 	}
416 
417 	drm_connector_list_iter_get(dev, &conn_iter);
418 	drm_for_each_connector_iter(connector, &conn_iter) {
419 		/* Ignore forced connectors. */
420 		if (connector->force)
421 			continue;
422 
423 		/* Ignore HPD capable connectors and connectors where we don't
424 		 * want any hotplug detection at all for polling. */
425 		if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
426 			continue;
427 
428 		old_status = connector->status;
429 		/* if we are connected and don't want to poll for disconnect
430 		   skip it */
431 		if (old_status == connector_status_connected &&
432 		    !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
433 			continue;
434 
435 		repoll = true;
436 
437 		connector->status = drm_connector_detect(connector, false);
438 		if (old_status != connector->status) {
439 			const char *old, *new;
440 
441 			/*
442 			 * The poll work sets force=false when calling detect so
443 			 * that drivers can avoid to do disruptive tests (e.g.
444 			 * when load detect cycles could cause flickering on
445 			 * other, running displays). This bears the risk that we
446 			 * flip-flop between unknown here in the poll work and
447 			 * the real state when userspace forces a full detect
448 			 * call after receiving a hotplug event due to this
449 			 * change.
450 			 *
451 			 * Hence clamp an unknown detect status to the old
452 			 * value.
453 			 */
454 			if (connector->status == connector_status_unknown) {
455 				connector->status = old_status;
456 				continue;
457 			}
458 
459 			old = drm_get_connector_status_name(old_status);
460 			new = drm_get_connector_status_name(connector->status);
461 
462 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
463 				      "status updated from %s to %s\n",
464 				      connector->base.id,
465 				      connector->name,
466 				      old, new);
467 
468 			changed = true;
469 		}
470 	}
471 	drm_connector_list_iter_put(&conn_iter);
472 
473 	mutex_unlock(&dev->mode_config.mutex);
474 
475 out:
476 	if (changed)
477 		drm_kms_helper_hotplug_event(dev);
478 
479 	if (repoll)
480 		schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
481 }
482 
483 /**
484  * drm_kms_helper_poll_disable - disable output polling
485  * @dev: drm_device
486  *
487  * This function disables the output polling work.
488  *
489  * Drivers can call this helper from their device suspend implementation. It is
490  * not an error to call this even when output polling isn't enabled or already
491  * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
492  *
493  * Note that calls to enable and disable polling must be strictly ordered, which
494  * is automatically the case when they're only call from suspend/resume
495  * callbacks.
496  */
497 void drm_kms_helper_poll_disable(struct drm_device *dev)
498 {
499 	if (!dev->mode_config.poll_enabled)
500 		return;
501 	cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
502 }
503 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
504 
505 /**
506  * drm_kms_helper_poll_init - initialize and enable output polling
507  * @dev: drm_device
508  *
509  * This function intializes and then also enables output polling support for
510  * @dev. Drivers which do not have reliable hotplug support in hardware can use
511  * this helper infrastructure to regularly poll such connectors for changes in
512  * their connection state.
513  *
514  * Drivers can control which connectors are polled by setting the
515  * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
516  * connectors where probing live outputs can result in visual distortion drivers
517  * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
518  * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
519  * completely ignored by the polling logic.
520  *
521  * Note that a connector can be both polled and probed from the hotplug handler,
522  * in case the hotplug interrupt is known to be unreliable.
523  */
524 void drm_kms_helper_poll_init(struct drm_device *dev)
525 {
526 	INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
527 	dev->mode_config.poll_enabled = true;
528 
529 	drm_kms_helper_poll_enable(dev);
530 }
531 EXPORT_SYMBOL(drm_kms_helper_poll_init);
532 
533 /**
534  * drm_kms_helper_poll_fini - disable output polling and clean it up
535  * @dev: drm_device
536  */
537 void drm_kms_helper_poll_fini(struct drm_device *dev)
538 {
539 	drm_kms_helper_poll_disable(dev);
540 }
541 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
542 
543 /**
544  * drm_helper_hpd_irq_event - hotplug processing
545  * @dev: drm_device
546  *
547  * Drivers can use this helper function to run a detect cycle on all connectors
548  * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
549  * other connectors are ignored, which is useful to avoid reprobing fixed
550  * panels.
551  *
552  * This helper function is useful for drivers which can't or don't track hotplug
553  * interrupts for each connector.
554  *
555  * Drivers which support hotplug interrupts for each connector individually and
556  * which have a more fine-grained detect logic should bypass this code and
557  * directly call drm_kms_helper_hotplug_event() in case the connector state
558  * changed.
559  *
560  * This function must be called from process context with no mode
561  * setting locks held.
562  *
563  * Note that a connector can be both polled and probed from the hotplug handler,
564  * in case the hotplug interrupt is known to be unreliable.
565  */
566 bool drm_helper_hpd_irq_event(struct drm_device *dev)
567 {
568 	struct drm_connector *connector;
569 	struct drm_connector_list_iter conn_iter;
570 	enum drm_connector_status old_status;
571 	bool changed = false;
572 
573 	if (!dev->mode_config.poll_enabled)
574 		return false;
575 
576 	mutex_lock(&dev->mode_config.mutex);
577 	drm_connector_list_iter_get(dev, &conn_iter);
578 	drm_for_each_connector_iter(connector, &conn_iter) {
579 		/* Only handle HPD capable connectors. */
580 		if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
581 			continue;
582 
583 		old_status = connector->status;
584 
585 		connector->status = drm_connector_detect(connector, false);
586 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
587 			      connector->base.id,
588 			      connector->name,
589 			      drm_get_connector_status_name(old_status),
590 			      drm_get_connector_status_name(connector->status));
591 		if (old_status != connector->status)
592 			changed = true;
593 	}
594 	drm_connector_list_iter_put(&conn_iter);
595 	mutex_unlock(&dev->mode_config.mutex);
596 
597 	if (changed)
598 		drm_kms_helper_hotplug_event(dev);
599 
600 	return changed;
601 }
602 EXPORT_SYMBOL(drm_helper_hpd_irq_event);
603