xref: /linux/drivers/gpu/drm/drm_probe_helper.c (revision ee15c8bf5d77a306614bdefe33828310662dee05)
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_fourcc.h>
40 #include <drm/drm_modeset_helper_vtables.h>
41 #include <drm/drm_print.h>
42 #include <drm/drm_probe_helper.h>
43 #include <drm/drm_sysfs.h>
44 
45 #include "drm_crtc_helper_internal.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 &drm_connector_funcs.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  * The probe helpers share the function table structures with other display
63  * helper libraries. See &struct drm_connector_helper_funcs for the details.
64  */
65 
66 static bool drm_kms_helper_poll = true;
67 module_param_named(poll, drm_kms_helper_poll, bool, 0600);
68 
69 static enum drm_mode_status
70 drm_mode_validate_flag(const struct drm_display_mode *mode,
71 		       int flags)
72 {
73 	if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
74 	    !(flags & DRM_MODE_FLAG_INTERLACE))
75 		return MODE_NO_INTERLACE;
76 
77 	if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
78 	    !(flags & DRM_MODE_FLAG_DBLSCAN))
79 		return MODE_NO_DBLESCAN;
80 
81 	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) &&
82 	    !(flags & DRM_MODE_FLAG_3D_MASK))
83 		return MODE_NO_STEREO;
84 
85 	return MODE_OK;
86 }
87 
88 static int
89 drm_mode_validate_pipeline(struct drm_display_mode *mode,
90 			   struct drm_connector *connector,
91 			   struct drm_modeset_acquire_ctx *ctx,
92 			   enum drm_mode_status *status)
93 {
94 	struct drm_device *dev = connector->dev;
95 	struct drm_encoder *encoder;
96 	int ret;
97 
98 	/* Step 1: Validate against connector */
99 	ret = drm_connector_mode_valid(connector, mode, ctx, status);
100 	if (ret || *status != MODE_OK)
101 		return ret;
102 
103 	/* Step 2: Validate against encoders and crtcs */
104 	drm_connector_for_each_possible_encoder(connector, encoder) {
105 		struct drm_bridge *bridge;
106 		struct drm_crtc *crtc;
107 
108 		*status = drm_encoder_mode_valid(encoder, mode);
109 		if (*status != MODE_OK) {
110 			/* No point in continuing for crtc check as this encoder
111 			 * will not accept the mode anyway. If all encoders
112 			 * reject the mode then, at exit, ret will not be
113 			 * MODE_OK. */
114 			continue;
115 		}
116 
117 		bridge = drm_bridge_chain_get_first_bridge(encoder);
118 		*status = drm_bridge_chain_mode_valid(bridge,
119 						      &connector->display_info,
120 						      mode);
121 		if (*status != MODE_OK) {
122 			/* There is also no point in continuing for crtc check
123 			 * here. */
124 			continue;
125 		}
126 
127 		drm_for_each_crtc(crtc, dev) {
128 			if (!drm_encoder_crtc_ok(encoder, crtc))
129 				continue;
130 
131 			*status = drm_crtc_mode_valid(crtc, mode);
132 			if (*status == MODE_OK) {
133 				/* If we get to this point there is at least
134 				 * one combination of encoder+crtc that works
135 				 * for this mode. Lets return now. */
136 				return 0;
137 			}
138 		}
139 	}
140 
141 	return 0;
142 }
143 
144 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
145 {
146 	struct drm_cmdline_mode *cmdline_mode;
147 	struct drm_display_mode *mode;
148 
149 	cmdline_mode = &connector->cmdline_mode;
150 	if (!cmdline_mode->specified)
151 		return 0;
152 
153 	/* Only add a GTF mode if we find no matching probed modes */
154 	list_for_each_entry(mode, &connector->probed_modes, head) {
155 		if (mode->hdisplay != cmdline_mode->xres ||
156 		    mode->vdisplay != cmdline_mode->yres)
157 			continue;
158 
159 		if (cmdline_mode->refresh_specified) {
160 			/* The probed mode's vrefresh is set until later */
161 			if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
162 				continue;
163 		}
164 
165 		/* Mark the matching mode as being preferred by the user */
166 		mode->type |= DRM_MODE_TYPE_USERDEF;
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 
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 
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 
202 int
203 drm_connector_mode_valid(struct drm_connector *connector,
204 			 struct drm_display_mode *mode,
205 			 struct drm_modeset_acquire_ctx *ctx,
206 			 enum drm_mode_status *status)
207 {
208 	const struct drm_connector_helper_funcs *connector_funcs =
209 		connector->helper_private;
210 	int ret = 0;
211 
212 	if (!connector_funcs)
213 		*status = MODE_OK;
214 	else if (connector_funcs->mode_valid_ctx)
215 		ret = connector_funcs->mode_valid_ctx(connector, mode, ctx,
216 						      status);
217 	else if (connector_funcs->mode_valid)
218 		*status = connector_funcs->mode_valid(connector, mode);
219 	else
220 		*status = MODE_OK;
221 
222 	return ret;
223 }
224 
225 static void drm_kms_helper_disable_hpd(struct drm_device *dev)
226 {
227 	struct drm_connector *connector;
228 	struct drm_connector_list_iter conn_iter;
229 
230 	drm_connector_list_iter_begin(dev, &conn_iter);
231 	drm_for_each_connector_iter(connector, &conn_iter) {
232 		const struct drm_connector_helper_funcs *funcs =
233 			connector->helper_private;
234 
235 		if (funcs && funcs->disable_hpd)
236 			funcs->disable_hpd(connector);
237 	}
238 	drm_connector_list_iter_end(&conn_iter);
239 }
240 
241 static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
242 {
243 	bool poll = false;
244 	struct drm_connector *connector;
245 	struct drm_connector_list_iter conn_iter;
246 
247 	drm_connector_list_iter_begin(dev, &conn_iter);
248 	drm_for_each_connector_iter(connector, &conn_iter) {
249 		const struct drm_connector_helper_funcs *funcs =
250 			connector->helper_private;
251 
252 		if (funcs && funcs->enable_hpd)
253 			funcs->enable_hpd(connector);
254 
255 		if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
256 					 DRM_CONNECTOR_POLL_DISCONNECT))
257 			poll = true;
258 	}
259 	drm_connector_list_iter_end(&conn_iter);
260 
261 	return poll;
262 }
263 
264 #define DRM_OUTPUT_POLL_PERIOD (10*HZ)
265 static void reschedule_output_poll_work(struct drm_device *dev)
266 {
267 	unsigned long delay = DRM_OUTPUT_POLL_PERIOD;
268 
269 	if (dev->mode_config.delayed_event)
270 		/*
271 		 * FIXME:
272 		 *
273 		 * Use short (1s) delay to handle the initial delayed event.
274 		 * This delay should not be needed, but Optimus/nouveau will
275 		 * fail in a mysterious way if the delayed event is handled as
276 		 * soon as possible like it is done in
277 		 * drm_helper_probe_single_connector_modes() in case the poll
278 		 * was enabled before.
279 		 */
280 		delay = HZ;
281 
282 	schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
283 }
284 
285 /**
286  * drm_kms_helper_poll_enable - re-enable output polling.
287  * @dev: drm_device
288  *
289  * This function re-enables the output polling work, after it has been
290  * temporarily disabled using drm_kms_helper_poll_disable(), for example over
291  * suspend/resume.
292  *
293  * Drivers can call this helper from their device resume implementation. It is
294  * not an error to call this even when output polling isn't enabled.
295  *
296  * If device polling was never initialized before, this call will trigger a
297  * warning and return.
298  *
299  * Note that calls to enable and disable polling must be strictly ordered, which
300  * is automatically the case when they're only call from suspend/resume
301  * callbacks.
302  */
303 void drm_kms_helper_poll_enable(struct drm_device *dev)
304 {
305 	if (drm_WARN_ON_ONCE(dev, !dev->mode_config.poll_enabled) ||
306 	    !drm_kms_helper_poll || dev->mode_config.poll_running)
307 		return;
308 
309 	if (drm_kms_helper_enable_hpd(dev) ||
310 	    dev->mode_config.delayed_event)
311 		reschedule_output_poll_work(dev);
312 
313 	dev->mode_config.poll_running = true;
314 }
315 EXPORT_SYMBOL(drm_kms_helper_poll_enable);
316 
317 /**
318  * drm_kms_helper_poll_reschedule - reschedule the output polling work
319  * @dev: drm_device
320  *
321  * This function reschedules the output polling work, after polling for a
322  * connector has been enabled.
323  *
324  * Drivers must call this helper after enabling polling for a connector by
325  * setting %DRM_CONNECTOR_POLL_CONNECT / %DRM_CONNECTOR_POLL_DISCONNECT flags
326  * in drm_connector::polled. Note that after disabling polling by clearing these
327  * flags for a connector will stop the output polling work automatically if
328  * the polling is disabled for all other connectors as well.
329  *
330  * The function can be called only after polling has been enabled by calling
331  * drm_kms_helper_poll_init() / drm_kms_helper_poll_enable().
332  */
333 void drm_kms_helper_poll_reschedule(struct drm_device *dev)
334 {
335 	if (dev->mode_config.poll_running)
336 		reschedule_output_poll_work(dev);
337 }
338 EXPORT_SYMBOL(drm_kms_helper_poll_reschedule);
339 
340 static enum drm_connector_status
341 drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
342 {
343 	const struct drm_connector_helper_funcs *funcs = connector->helper_private;
344 	struct drm_modeset_acquire_ctx ctx;
345 	int ret;
346 
347 	drm_modeset_acquire_init(&ctx, 0);
348 
349 retry:
350 	ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
351 	if (!ret) {
352 		if (funcs->detect_ctx)
353 			ret = funcs->detect_ctx(connector, &ctx, force);
354 		else if (connector->funcs->detect)
355 			ret = connector->funcs->detect(connector, force);
356 		else
357 			ret = connector_status_connected;
358 	}
359 
360 	if (ret == -EDEADLK) {
361 		drm_modeset_backoff(&ctx);
362 		goto retry;
363 	}
364 
365 	if (WARN_ON(ret < 0))
366 		ret = connector_status_unknown;
367 
368 	if (ret != connector->status)
369 		connector->epoch_counter += 1;
370 
371 	drm_modeset_drop_locks(&ctx);
372 	drm_modeset_acquire_fini(&ctx);
373 
374 	return ret;
375 }
376 
377 /**
378  * drm_helper_probe_detect - probe connector status
379  * @connector: connector to probe
380  * @ctx: acquire_ctx, or NULL to let this function handle locking.
381  * @force: Whether destructive probe operations should be performed.
382  *
383  * This function calls the detect callbacks of the connector.
384  * This function returns &drm_connector_status, or
385  * if @ctx is set, it might also return -EDEADLK.
386  */
387 int
388 drm_helper_probe_detect(struct drm_connector *connector,
389 			struct drm_modeset_acquire_ctx *ctx,
390 			bool force)
391 {
392 	const struct drm_connector_helper_funcs *funcs = connector->helper_private;
393 	struct drm_device *dev = connector->dev;
394 	int ret;
395 
396 	if (!ctx)
397 		return drm_helper_probe_detect_ctx(connector, force);
398 
399 	ret = drm_modeset_lock(&dev->mode_config.connection_mutex, ctx);
400 	if (ret)
401 		return ret;
402 
403 	if (funcs->detect_ctx)
404 		ret = funcs->detect_ctx(connector, ctx, force);
405 	else if (connector->funcs->detect)
406 		ret = connector->funcs->detect(connector, force);
407 	else
408 		ret = connector_status_connected;
409 
410 	if (ret != connector->status)
411 		connector->epoch_counter += 1;
412 
413 	return ret;
414 }
415 EXPORT_SYMBOL(drm_helper_probe_detect);
416 
417 static int drm_helper_probe_get_modes(struct drm_connector *connector)
418 {
419 	const struct drm_connector_helper_funcs *connector_funcs =
420 		connector->helper_private;
421 	int count;
422 
423 	count = connector_funcs->get_modes(connector);
424 
425 	/*
426 	 * Fallback for when DDC probe failed in drm_get_edid() and thus skipped
427 	 * override/firmware EDID.
428 	 */
429 	if (count == 0 && connector->status == connector_status_connected)
430 		count = drm_edid_override_connector_update(connector);
431 
432 	return count;
433 }
434 
435 static int __drm_helper_update_and_validate(struct drm_connector *connector,
436 					    uint32_t maxX, uint32_t maxY,
437 					    struct drm_modeset_acquire_ctx *ctx)
438 {
439 	struct drm_device *dev = connector->dev;
440 	struct drm_display_mode *mode;
441 	int mode_flags = 0;
442 	int ret;
443 
444 	drm_connector_list_update(connector);
445 
446 	if (connector->interlace_allowed)
447 		mode_flags |= DRM_MODE_FLAG_INTERLACE;
448 	if (connector->doublescan_allowed)
449 		mode_flags |= DRM_MODE_FLAG_DBLSCAN;
450 	if (connector->stereo_allowed)
451 		mode_flags |= DRM_MODE_FLAG_3D_MASK;
452 
453 	list_for_each_entry(mode, &connector->modes, head) {
454 		if (mode->status != MODE_OK)
455 			continue;
456 
457 		mode->status = drm_mode_validate_driver(dev, mode);
458 		if (mode->status != MODE_OK)
459 			continue;
460 
461 		mode->status = drm_mode_validate_size(mode, maxX, maxY);
462 		if (mode->status != MODE_OK)
463 			continue;
464 
465 		mode->status = drm_mode_validate_flag(mode, mode_flags);
466 		if (mode->status != MODE_OK)
467 			continue;
468 
469 		ret = drm_mode_validate_pipeline(mode, connector, ctx,
470 						 &mode->status);
471 		if (ret) {
472 			drm_dbg_kms(dev,
473 				    "drm_mode_validate_pipeline failed: %d\n",
474 				    ret);
475 
476 			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK))
477 				mode->status = MODE_ERROR;
478 			else
479 				return -EDEADLK;
480 		}
481 
482 		if (mode->status != MODE_OK)
483 			continue;
484 		mode->status = drm_mode_validate_ycbcr420(mode, connector);
485 	}
486 
487 	return 0;
488 }
489 
490 /**
491  * drm_helper_probe_single_connector_modes - get complete set of display modes
492  * @connector: connector to probe
493  * @maxX: max width for modes
494  * @maxY: max height for modes
495  *
496  * Based on the helper callbacks implemented by @connector in struct
497  * &drm_connector_helper_funcs try to detect all valid modes.  Modes will first
498  * be added to the connector's probed_modes list, then culled (based on validity
499  * and the @maxX, @maxY parameters) and put into the normal modes list.
500  *
501  * Intended to be used as a generic implementation of the
502  * &drm_connector_funcs.fill_modes() vfunc for drivers that use the CRTC helpers
503  * for output mode filtering and detection.
504  *
505  * The basic procedure is as follows
506  *
507  * 1. All modes currently on the connector's modes list are marked as stale
508  *
509  * 2. New modes are added to the connector's probed_modes list with
510  *    drm_mode_probed_add(). New modes start their life with status as OK.
511  *    Modes are added from a single source using the following priority order.
512  *
513  *    - &drm_connector_helper_funcs.get_modes vfunc
514  *    - if the connector status is connector_status_connected, standard
515  *      VESA DMT modes up to 1024x768 are automatically added
516  *      (drm_add_modes_noedid())
517  *
518  *    Finally modes specified via the kernel command line (video=...) are
519  *    added in addition to what the earlier probes produced
520  *    (drm_helper_probe_add_cmdline_mode()). These modes are generated
521  *    using the VESA GTF/CVT formulas.
522  *
523  * 3. Modes are moved from the probed_modes list to the modes list. Potential
524  *    duplicates are merged together (see drm_connector_list_update()).
525  *    After this step the probed_modes list will be empty again.
526  *
527  * 4. Any non-stale mode on the modes list then undergoes validation
528  *
529  *    - drm_mode_validate_basic() performs basic sanity checks
530  *    - drm_mode_validate_size() filters out modes larger than @maxX and @maxY
531  *      (if specified)
532  *    - drm_mode_validate_flag() checks the modes against basic connector
533  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
534  *    - the optional &drm_connector_helper_funcs.mode_valid or
535  *      &drm_connector_helper_funcs.mode_valid_ctx helpers can perform driver
536  *      and/or sink specific checks
537  *    - the optional &drm_crtc_helper_funcs.mode_valid,
538  *      &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid
539  *      helpers can perform driver and/or source specific checks which are also
540  *      enforced by the modeset/atomic helpers
541  *
542  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
543  *    accompanied by a debug message indicating the reason for the mode's
544  *    rejection (see drm_mode_prune_invalid()).
545  *
546  * Returns:
547  * The number of modes found on @connector.
548  */
549 int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
550 					    uint32_t maxX, uint32_t maxY)
551 {
552 	struct drm_device *dev = connector->dev;
553 	struct drm_display_mode *mode;
554 	int count = 0, ret;
555 	enum drm_connector_status old_status;
556 	struct drm_modeset_acquire_ctx ctx;
557 
558 	WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
559 
560 	drm_modeset_acquire_init(&ctx, 0);
561 
562 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
563 			connector->name);
564 
565 retry:
566 	ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
567 	if (ret == -EDEADLK) {
568 		drm_modeset_backoff(&ctx);
569 		goto retry;
570 	} else
571 		WARN_ON(ret < 0);
572 
573 	/* set all old modes to the stale state */
574 	list_for_each_entry(mode, &connector->modes, head)
575 		mode->status = MODE_STALE;
576 
577 	old_status = connector->status;
578 
579 	if (connector->force) {
580 		if (connector->force == DRM_FORCE_ON ||
581 		    connector->force == DRM_FORCE_ON_DIGITAL)
582 			connector->status = connector_status_connected;
583 		else
584 			connector->status = connector_status_disconnected;
585 		if (connector->funcs->force)
586 			connector->funcs->force(connector);
587 	} else {
588 		ret = drm_helper_probe_detect(connector, &ctx, true);
589 
590 		if (ret == -EDEADLK) {
591 			drm_modeset_backoff(&ctx);
592 			goto retry;
593 		} else if (WARN(ret < 0, "Invalid return value %i for connector detection\n", ret))
594 			ret = connector_status_unknown;
595 
596 		connector->status = ret;
597 	}
598 
599 	/*
600 	 * Normally either the driver's hpd code or the poll loop should
601 	 * pick up any changes and fire the hotplug event. But if
602 	 * userspace sneaks in a probe, we might miss a change. Hence
603 	 * check here, and if anything changed start the hotplug code.
604 	 */
605 	if (old_status != connector->status) {
606 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
607 			      connector->base.id,
608 			      connector->name,
609 			      drm_get_connector_status_name(old_status),
610 			      drm_get_connector_status_name(connector->status));
611 
612 		/*
613 		 * The hotplug event code might call into the fb
614 		 * helpers, and so expects that we do not hold any
615 		 * locks. Fire up the poll struct instead, it will
616 		 * disable itself again.
617 		 */
618 		dev->mode_config.delayed_event = true;
619 		if (dev->mode_config.poll_enabled)
620 			mod_delayed_work(system_wq,
621 					 &dev->mode_config.output_poll_work,
622 					 0);
623 	}
624 
625 	/*
626 	 * Re-enable polling in case the global poll config changed but polling
627 	 * is still initialized.
628 	 */
629 	if (dev->mode_config.poll_enabled)
630 		drm_kms_helper_poll_enable(dev);
631 
632 	if (connector->status == connector_status_disconnected) {
633 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
634 			connector->base.id, connector->name);
635 		drm_connector_update_edid_property(connector, NULL);
636 		drm_mode_prune_invalid(dev, &connector->modes, false);
637 		goto exit;
638 	}
639 
640 	count = drm_helper_probe_get_modes(connector);
641 
642 	if (count == 0 && (connector->status == connector_status_connected ||
643 			   connector->status == connector_status_unknown)) {
644 		count = drm_add_modes_noedid(connector, 1024, 768);
645 
646 		/*
647 		 * Section 4.2.2.6 (EDID Corruption Detection) of the DP 1.4a
648 		 * Link CTS specifies that 640x480 (the official "failsafe"
649 		 * mode) needs to be the default if there's no EDID.
650 		 */
651 		if (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort)
652 			drm_set_preferred_mode(connector, 640, 480);
653 	}
654 	count += drm_helper_probe_add_cmdline_mode(connector);
655 	if (count != 0) {
656 		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
657 		if (ret == -EDEADLK) {
658 			drm_modeset_backoff(&ctx);
659 			goto retry;
660 		}
661 	}
662 
663 	drm_mode_prune_invalid(dev, &connector->modes, true);
664 
665 	/*
666 	 * Displayport spec section 5.2.1.2 ("Video Timing Format") says that
667 	 * all detachable sinks shall support 640x480 @60Hz as a fail safe
668 	 * mode. If all modes were pruned, perhaps because they need more
669 	 * lanes or a higher pixel clock than available, at least try to add
670 	 * in 640x480.
671 	 */
672 	if (list_empty(&connector->modes) &&
673 	    connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort) {
674 		count = drm_add_modes_noedid(connector, 640, 480);
675 		ret = __drm_helper_update_and_validate(connector, maxX, maxY, &ctx);
676 		if (ret == -EDEADLK) {
677 			drm_modeset_backoff(&ctx);
678 			goto retry;
679 		}
680 		drm_mode_prune_invalid(dev, &connector->modes, true);
681 	}
682 
683 exit:
684 	drm_modeset_drop_locks(&ctx);
685 	drm_modeset_acquire_fini(&ctx);
686 
687 	if (list_empty(&connector->modes))
688 		return 0;
689 
690 	drm_mode_sort(&connector->modes);
691 
692 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
693 			connector->name);
694 	list_for_each_entry(mode, &connector->modes, head) {
695 		drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
696 		drm_mode_debug_printmodeline(mode);
697 	}
698 
699 	return count;
700 }
701 EXPORT_SYMBOL(drm_helper_probe_single_connector_modes);
702 
703 /**
704  * drm_kms_helper_hotplug_event - fire off KMS hotplug events
705  * @dev: drm_device whose connector state changed
706  *
707  * This function fires off the uevent for userspace and also calls the
708  * output_poll_changed function, which is most commonly used to inform the fbdev
709  * emulation code and allow it to update the fbcon output configuration.
710  *
711  * Drivers should call this from their hotplug handling code when a change is
712  * detected. Note that this function does not do any output detection of its
713  * own, like drm_helper_hpd_irq_event() does - this is assumed to be done by the
714  * driver already.
715  *
716  * This function must be called from process context with no mode
717  * setting locks held.
718  *
719  * If only a single connector has changed, consider calling
720  * drm_kms_helper_connector_hotplug_event() instead.
721  */
722 void drm_kms_helper_hotplug_event(struct drm_device *dev)
723 {
724 	/* send a uevent + call fbdev */
725 	drm_sysfs_hotplug_event(dev);
726 	if (dev->mode_config.funcs->output_poll_changed)
727 		dev->mode_config.funcs->output_poll_changed(dev);
728 
729 	drm_client_dev_hotplug(dev);
730 }
731 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
732 
733 /**
734  * drm_kms_helper_connector_hotplug_event - fire off a KMS connector hotplug event
735  * @connector: drm_connector which has changed
736  *
737  * This is the same as drm_kms_helper_hotplug_event(), except it fires a more
738  * fine-grained uevent for a single connector.
739  */
740 void drm_kms_helper_connector_hotplug_event(struct drm_connector *connector)
741 {
742 	struct drm_device *dev = connector->dev;
743 
744 	/* send a uevent + call fbdev */
745 	drm_sysfs_connector_hotplug_event(connector);
746 	if (dev->mode_config.funcs->output_poll_changed)
747 		dev->mode_config.funcs->output_poll_changed(dev);
748 
749 	drm_client_dev_hotplug(dev);
750 }
751 EXPORT_SYMBOL(drm_kms_helper_connector_hotplug_event);
752 
753 static void output_poll_execute(struct work_struct *work)
754 {
755 	struct delayed_work *delayed_work = to_delayed_work(work);
756 	struct drm_device *dev = container_of(delayed_work, struct drm_device, mode_config.output_poll_work);
757 	struct drm_connector *connector;
758 	struct drm_connector_list_iter conn_iter;
759 	enum drm_connector_status old_status;
760 	bool repoll = false, changed;
761 	u64 old_epoch_counter;
762 
763 	if (!dev->mode_config.poll_enabled)
764 		return;
765 
766 	/* Pick up any changes detected by the probe functions. */
767 	changed = dev->mode_config.delayed_event;
768 	dev->mode_config.delayed_event = false;
769 
770 	if (!drm_kms_helper_poll && dev->mode_config.poll_running) {
771 		drm_kms_helper_disable_hpd(dev);
772 		dev->mode_config.poll_running = false;
773 		goto out;
774 	}
775 
776 	if (!mutex_trylock(&dev->mode_config.mutex)) {
777 		repoll = true;
778 		goto out;
779 	}
780 
781 	drm_connector_list_iter_begin(dev, &conn_iter);
782 	drm_for_each_connector_iter(connector, &conn_iter) {
783 		/* Ignore forced connectors. */
784 		if (connector->force)
785 			continue;
786 
787 		/* Ignore HPD capable connectors and connectors where we don't
788 		 * want any hotplug detection at all for polling. */
789 		if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
790 			continue;
791 
792 		old_status = connector->status;
793 		/* if we are connected and don't want to poll for disconnect
794 		   skip it */
795 		if (old_status == connector_status_connected &&
796 		    !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
797 			continue;
798 
799 		repoll = true;
800 
801 		old_epoch_counter = connector->epoch_counter;
802 		connector->status = drm_helper_probe_detect(connector, NULL, false);
803 		if (old_epoch_counter != connector->epoch_counter) {
804 			const char *old, *new;
805 
806 			/*
807 			 * The poll work sets force=false when calling detect so
808 			 * that drivers can avoid to do disruptive tests (e.g.
809 			 * when load detect cycles could cause flickering on
810 			 * other, running displays). This bears the risk that we
811 			 * flip-flop between unknown here in the poll work and
812 			 * the real state when userspace forces a full detect
813 			 * call after receiving a hotplug event due to this
814 			 * change.
815 			 *
816 			 * Hence clamp an unknown detect status to the old
817 			 * value.
818 			 */
819 			if (connector->status == connector_status_unknown) {
820 				connector->status = old_status;
821 				continue;
822 			}
823 
824 			old = drm_get_connector_status_name(old_status);
825 			new = drm_get_connector_status_name(connector->status);
826 
827 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
828 				      "status updated from %s to %s\n",
829 				      connector->base.id,
830 				      connector->name,
831 				      old, new);
832 			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] epoch counter %llu -> %llu\n",
833 				      connector->base.id, connector->name,
834 				      old_epoch_counter, connector->epoch_counter);
835 
836 			changed = true;
837 		}
838 	}
839 	drm_connector_list_iter_end(&conn_iter);
840 
841 	mutex_unlock(&dev->mode_config.mutex);
842 
843 out:
844 	if (changed)
845 		drm_kms_helper_hotplug_event(dev);
846 
847 	if (repoll)
848 		schedule_delayed_work(delayed_work, DRM_OUTPUT_POLL_PERIOD);
849 }
850 
851 /**
852  * drm_kms_helper_is_poll_worker - is %current task an output poll worker?
853  *
854  * Determine if %current task is an output poll worker.  This can be used
855  * to select distinct code paths for output polling versus other contexts.
856  *
857  * One use case is to avoid a deadlock between the output poll worker and
858  * the autosuspend worker wherein the latter waits for polling to finish
859  * upon calling drm_kms_helper_poll_disable(), while the former waits for
860  * runtime suspend to finish upon calling pm_runtime_get_sync() in a
861  * connector ->detect hook.
862  */
863 bool drm_kms_helper_is_poll_worker(void)
864 {
865 	struct work_struct *work = current_work();
866 
867 	return work && work->func == output_poll_execute;
868 }
869 EXPORT_SYMBOL(drm_kms_helper_is_poll_worker);
870 
871 /**
872  * drm_kms_helper_poll_disable - disable output polling
873  * @dev: drm_device
874  *
875  * This function disables the output polling work.
876  *
877  * Drivers can call this helper from their device suspend implementation. It is
878  * not an error to call this even when output polling isn't enabled or already
879  * disabled. Polling is re-enabled by calling drm_kms_helper_poll_enable().
880  *
881  * If however, the polling was never initialized, this call will trigger a
882  * warning and return
883  *
884  * Note that calls to enable and disable polling must be strictly ordered, which
885  * is automatically the case when they're only call from suspend/resume
886  * callbacks.
887  */
888 void drm_kms_helper_poll_disable(struct drm_device *dev)
889 {
890 	if (drm_WARN_ON(dev, !dev->mode_config.poll_enabled))
891 		return;
892 
893 	if (dev->mode_config.poll_running)
894 		drm_kms_helper_disable_hpd(dev);
895 
896 	cancel_delayed_work_sync(&dev->mode_config.output_poll_work);
897 
898 	dev->mode_config.poll_running = false;
899 }
900 EXPORT_SYMBOL(drm_kms_helper_poll_disable);
901 
902 /**
903  * drm_kms_helper_poll_init - initialize and enable output polling
904  * @dev: drm_device
905  *
906  * This function initializes and then also enables output polling support for
907  * @dev. Drivers which do not have reliable hotplug support in hardware can use
908  * this helper infrastructure to regularly poll such connectors for changes in
909  * their connection state.
910  *
911  * Drivers can control which connectors are polled by setting the
912  * DRM_CONNECTOR_POLL_CONNECT and DRM_CONNECTOR_POLL_DISCONNECT flags. On
913  * connectors where probing live outputs can result in visual distortion drivers
914  * should not set the DRM_CONNECTOR_POLL_DISCONNECT flag to avoid this.
915  * Connectors which have no flag or only DRM_CONNECTOR_POLL_HPD set are
916  * completely ignored by the polling logic.
917  *
918  * Note that a connector can be both polled and probed from the hotplug handler,
919  * in case the hotplug interrupt is known to be unreliable.
920  */
921 void drm_kms_helper_poll_init(struct drm_device *dev)
922 {
923 	INIT_DELAYED_WORK(&dev->mode_config.output_poll_work, output_poll_execute);
924 	dev->mode_config.poll_enabled = true;
925 
926 	drm_kms_helper_poll_enable(dev);
927 }
928 EXPORT_SYMBOL(drm_kms_helper_poll_init);
929 
930 /**
931  * drm_kms_helper_poll_fini - disable output polling and clean it up
932  * @dev: drm_device
933  */
934 void drm_kms_helper_poll_fini(struct drm_device *dev)
935 {
936 	if (!dev->mode_config.poll_enabled)
937 		return;
938 
939 	drm_kms_helper_poll_disable(dev);
940 
941 	dev->mode_config.poll_enabled = false;
942 }
943 EXPORT_SYMBOL(drm_kms_helper_poll_fini);
944 
945 static bool check_connector_changed(struct drm_connector *connector)
946 {
947 	struct drm_device *dev = connector->dev;
948 	enum drm_connector_status old_status;
949 	u64 old_epoch_counter;
950 
951 	/* Only handle HPD capable connectors. */
952 	drm_WARN_ON(dev, !(connector->polled & DRM_CONNECTOR_POLL_HPD));
953 
954 	drm_WARN_ON(dev, !mutex_is_locked(&dev->mode_config.mutex));
955 
956 	old_status = connector->status;
957 	old_epoch_counter = connector->epoch_counter;
958 	connector->status = drm_helper_probe_detect(connector, NULL, false);
959 
960 	if (old_epoch_counter == connector->epoch_counter) {
961 		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Same epoch counter %llu\n",
962 			    connector->base.id,
963 			    connector->name,
964 			    connector->epoch_counter);
965 
966 		return false;
967 	}
968 
969 	drm_dbg_kms(dev, "[CONNECTOR:%d:%s] status updated from %s to %s\n",
970 		    connector->base.id,
971 		    connector->name,
972 		    drm_get_connector_status_name(old_status),
973 		    drm_get_connector_status_name(connector->status));
974 
975 	drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Changed epoch counter %llu => %llu\n",
976 		    connector->base.id,
977 		    connector->name,
978 		    old_epoch_counter,
979 		    connector->epoch_counter);
980 
981 	return true;
982 }
983 
984 /**
985  * drm_connector_helper_hpd_irq_event - hotplug processing
986  * @connector: drm_connector
987  *
988  * Drivers can use this helper function to run a detect cycle on a connector
989  * which has the DRM_CONNECTOR_POLL_HPD flag set in its &polled member.
990  *
991  * This helper function is useful for drivers which can track hotplug
992  * interrupts for a single connector. Drivers that want to send a
993  * hotplug event for all connectors or can't track hotplug interrupts
994  * per connector need to use drm_helper_hpd_irq_event().
995  *
996  * This function must be called from process context with no mode
997  * setting locks held.
998  *
999  * Note that a connector can be both polled and probed from the hotplug
1000  * handler, in case the hotplug interrupt is known to be unreliable.
1001  *
1002  * Returns:
1003  * A boolean indicating whether the connector status changed or not
1004  */
1005 bool drm_connector_helper_hpd_irq_event(struct drm_connector *connector)
1006 {
1007 	struct drm_device *dev = connector->dev;
1008 	bool changed;
1009 
1010 	mutex_lock(&dev->mode_config.mutex);
1011 	changed = check_connector_changed(connector);
1012 	mutex_unlock(&dev->mode_config.mutex);
1013 
1014 	if (changed) {
1015 		drm_kms_helper_connector_hotplug_event(connector);
1016 		drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Sent hotplug event\n",
1017 			    connector->base.id,
1018 			    connector->name);
1019 	}
1020 
1021 	return changed;
1022 }
1023 EXPORT_SYMBOL(drm_connector_helper_hpd_irq_event);
1024 
1025 /**
1026  * drm_helper_hpd_irq_event - hotplug processing
1027  * @dev: drm_device
1028  *
1029  * Drivers can use this helper function to run a detect cycle on all connectors
1030  * which have the DRM_CONNECTOR_POLL_HPD flag set in their &polled member. All
1031  * other connectors are ignored, which is useful to avoid reprobing fixed
1032  * panels.
1033  *
1034  * This helper function is useful for drivers which can't or don't track hotplug
1035  * interrupts for each connector.
1036  *
1037  * Drivers which support hotplug interrupts for each connector individually and
1038  * which have a more fine-grained detect logic can use
1039  * drm_connector_helper_hpd_irq_event(). Alternatively, they should bypass this
1040  * code and directly call drm_kms_helper_hotplug_event() in case the connector
1041  * state changed.
1042  *
1043  * This function must be called from process context with no mode
1044  * setting locks held.
1045  *
1046  * Note that a connector can be both polled and probed from the hotplug handler,
1047  * in case the hotplug interrupt is known to be unreliable.
1048  *
1049  * Returns:
1050  * A boolean indicating whether the connector status changed or not
1051  */
1052 bool drm_helper_hpd_irq_event(struct drm_device *dev)
1053 {
1054 	struct drm_connector *connector, *first_changed_connector = NULL;
1055 	struct drm_connector_list_iter conn_iter;
1056 	int changed = 0;
1057 
1058 	if (!dev->mode_config.poll_enabled)
1059 		return false;
1060 
1061 	mutex_lock(&dev->mode_config.mutex);
1062 	drm_connector_list_iter_begin(dev, &conn_iter);
1063 	drm_for_each_connector_iter(connector, &conn_iter) {
1064 		/* Only handle HPD capable connectors. */
1065 		if (!(connector->polled & DRM_CONNECTOR_POLL_HPD))
1066 			continue;
1067 
1068 		if (check_connector_changed(connector)) {
1069 			if (!first_changed_connector) {
1070 				drm_connector_get(connector);
1071 				first_changed_connector = connector;
1072 			}
1073 
1074 			changed++;
1075 		}
1076 	}
1077 	drm_connector_list_iter_end(&conn_iter);
1078 	mutex_unlock(&dev->mode_config.mutex);
1079 
1080 	if (changed == 1)
1081 		drm_kms_helper_connector_hotplug_event(first_changed_connector);
1082 	else if (changed > 0)
1083 		drm_kms_helper_hotplug_event(dev);
1084 
1085 	if (first_changed_connector)
1086 		drm_connector_put(first_changed_connector);
1087 
1088 	return changed;
1089 }
1090 EXPORT_SYMBOL(drm_helper_hpd_irq_event);
1091 
1092 /**
1093  * drm_crtc_helper_mode_valid_fixed - Validates a display mode
1094  * @crtc: the crtc
1095  * @mode: the mode to validate
1096  * @fixed_mode: the display hardware's mode
1097  *
1098  * Returns:
1099  * MODE_OK on success, or another mode-status code otherwise.
1100  */
1101 enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,
1102 						      const struct drm_display_mode *mode,
1103 						      const struct drm_display_mode *fixed_mode)
1104 {
1105 	if (mode->hdisplay != fixed_mode->hdisplay && mode->vdisplay != fixed_mode->vdisplay)
1106 		return MODE_ONE_SIZE;
1107 	else if (mode->hdisplay != fixed_mode->hdisplay)
1108 		return MODE_ONE_WIDTH;
1109 	else if (mode->vdisplay != fixed_mode->vdisplay)
1110 		return MODE_ONE_HEIGHT;
1111 
1112 	return MODE_OK;
1113 }
1114 EXPORT_SYMBOL(drm_crtc_helper_mode_valid_fixed);
1115 
1116 /**
1117  * drm_connector_helper_get_modes_fixed - Duplicates a display mode for a connector
1118  * @connector: the connector
1119  * @fixed_mode: the display hardware's mode
1120  *
1121  * This function duplicates a display modes for a connector. Drivers for hardware
1122  * that only supports a single fixed mode can use this function in their connector's
1123  * get_modes helper.
1124  *
1125  * Returns:
1126  * The number of created modes.
1127  */
1128 int drm_connector_helper_get_modes_fixed(struct drm_connector *connector,
1129 					 const struct drm_display_mode *fixed_mode)
1130 {
1131 	struct drm_device *dev = connector->dev;
1132 	struct drm_display_mode *mode;
1133 
1134 	mode = drm_mode_duplicate(dev, fixed_mode);
1135 	if (!mode) {
1136 		drm_err(dev, "Failed to duplicate mode " DRM_MODE_FMT "\n",
1137 			DRM_MODE_ARG(fixed_mode));
1138 		return 0;
1139 	}
1140 
1141 	if (mode->name[0] == '\0')
1142 		drm_mode_set_name(mode);
1143 
1144 	mode->type |= DRM_MODE_TYPE_PREFERRED;
1145 	drm_mode_probed_add(connector, mode);
1146 
1147 	if (mode->width_mm)
1148 		connector->display_info.width_mm = mode->width_mm;
1149 	if (mode->height_mm)
1150 		connector->display_info.height_mm = mode->height_mm;
1151 
1152 	return 1;
1153 }
1154 EXPORT_SYMBOL(drm_connector_helper_get_modes_fixed);
1155 
1156 /**
1157  * drm_connector_helper_get_modes - Read EDID and update connector.
1158  * @connector: The connector
1159  *
1160  * Read the EDID using drm_edid_read() (which requires that connector->ddc is
1161  * set), and update the connector using the EDID.
1162  *
1163  * This can be used as the "default" connector helper .get_modes() hook if the
1164  * driver does not need any special processing. This is sets the example what
1165  * custom .get_modes() hooks should do regarding EDID read and connector update.
1166  *
1167  * Returns: Number of modes.
1168  */
1169 int drm_connector_helper_get_modes(struct drm_connector *connector)
1170 {
1171 	const struct drm_edid *drm_edid;
1172 	int count;
1173 
1174 	drm_edid = drm_edid_read(connector);
1175 
1176 	/*
1177 	 * Unconditionally update the connector. If the EDID was read
1178 	 * successfully, fill in the connector information derived from the
1179 	 * EDID. Otherwise, if the EDID is NULL, clear the connector
1180 	 * information.
1181 	 */
1182 	drm_edid_connector_update(connector, drm_edid);
1183 
1184 	count = drm_edid_connector_add_modes(connector);
1185 
1186 	drm_edid_free(drm_edid);
1187 
1188 	return count;
1189 }
1190 EXPORT_SYMBOL(drm_connector_helper_get_modes);
1191 
1192 /**
1193  * drm_connector_helper_tv_get_modes - Fills the modes availables to a TV connector
1194  * @connector: The connector
1195  *
1196  * Fills the available modes for a TV connector based on the supported
1197  * TV modes, and the default mode expressed by the kernel command line.
1198  *
1199  * This can be used as the default TV connector helper .get_modes() hook
1200  * if the driver does not need any special processing.
1201  *
1202  * Returns:
1203  * The number of modes added to the connector.
1204  */
1205 int drm_connector_helper_tv_get_modes(struct drm_connector *connector)
1206 {
1207 	struct drm_device *dev = connector->dev;
1208 	struct drm_property *tv_mode_property =
1209 		dev->mode_config.tv_mode_property;
1210 	struct drm_cmdline_mode *cmdline = &connector->cmdline_mode;
1211 	unsigned int ntsc_modes = BIT(DRM_MODE_TV_MODE_NTSC) |
1212 		BIT(DRM_MODE_TV_MODE_NTSC_443) |
1213 		BIT(DRM_MODE_TV_MODE_NTSC_J) |
1214 		BIT(DRM_MODE_TV_MODE_PAL_M);
1215 	unsigned int pal_modes = BIT(DRM_MODE_TV_MODE_PAL) |
1216 		BIT(DRM_MODE_TV_MODE_PAL_N) |
1217 		BIT(DRM_MODE_TV_MODE_SECAM);
1218 	unsigned int tv_modes[2] = { UINT_MAX, UINT_MAX };
1219 	unsigned int i, supported_tv_modes = 0;
1220 
1221 	if (!tv_mode_property)
1222 		return 0;
1223 
1224 	for (i = 0; i < tv_mode_property->num_values; i++)
1225 		supported_tv_modes |= BIT(tv_mode_property->values[i]);
1226 
1227 	if ((supported_tv_modes & ntsc_modes) &&
1228 	    (supported_tv_modes & pal_modes)) {
1229 		uint64_t default_mode;
1230 
1231 		if (drm_object_property_get_default_value(&connector->base,
1232 							  tv_mode_property,
1233 							  &default_mode))
1234 			return 0;
1235 
1236 		if (cmdline->tv_mode_specified)
1237 			default_mode = cmdline->tv_mode;
1238 
1239 		if (BIT(default_mode) & ntsc_modes) {
1240 			tv_modes[0] = DRM_MODE_TV_MODE_NTSC;
1241 			tv_modes[1] = DRM_MODE_TV_MODE_PAL;
1242 		} else {
1243 			tv_modes[0] = DRM_MODE_TV_MODE_PAL;
1244 			tv_modes[1] = DRM_MODE_TV_MODE_NTSC;
1245 		}
1246 	} else if (supported_tv_modes & ntsc_modes) {
1247 		tv_modes[0] = DRM_MODE_TV_MODE_NTSC;
1248 	} else if (supported_tv_modes & pal_modes) {
1249 		tv_modes[0] = DRM_MODE_TV_MODE_PAL;
1250 	} else {
1251 		return 0;
1252 	}
1253 
1254 	for (i = 0; i < ARRAY_SIZE(tv_modes); i++) {
1255 		struct drm_display_mode *mode;
1256 
1257 		if (tv_modes[i] == DRM_MODE_TV_MODE_NTSC)
1258 			mode = drm_mode_analog_ntsc_480i(dev);
1259 		else if (tv_modes[i] == DRM_MODE_TV_MODE_PAL)
1260 			mode = drm_mode_analog_pal_576i(dev);
1261 		else
1262 			break;
1263 		if (!mode)
1264 			return i;
1265 		if (!i)
1266 			mode->type |= DRM_MODE_TYPE_PREFERRED;
1267 		drm_mode_probed_add(connector, mode);
1268 	}
1269 
1270 	return i;
1271 }
1272 EXPORT_SYMBOL(drm_connector_helper_tv_get_modes);
1273