summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/drm_crtc_helper.c
blob: 393114df88a3dbeb5326db27c7a16465fcf1550b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
/*
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 *
 * DRM core CRTC related functions
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 *
 * Authors:
 *      Keith Packard
 *	Eric Anholt <eric@anholt.net>
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */

#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/moduleparam.h>

#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_edid.h>

/**
 * DOC: overview
 *
 * The CRTC modeset helper library provides a default set_config implementation
 * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
 * the same callbacks which drivers can use to e.g. restore the modeset
 * configuration on resume with drm_helper_resume_force_mode().
 *
 * The driver callbacks are mostly compatible with the atomic modeset helpers,
 * except for the handling of the primary plane: Atomic helpers require that the
 * primary plane is implemented as a real standalone plane and not directly tied
 * to the CRTC state. For easier transition this library provides functions to
 * implement the old semantics required by the CRTC helpers using the new plane
 * and atomic helper callbacks.
 *
 * Drivers are strongly urged to convert to the atomic helpers (by way of first
 * converting to the plane helpers). New drivers must not use these functions
 * but need to implement the atomic interface instead, potentially using the
 * atomic helpers for that.
 */
MODULE_AUTHOR("David Airlie, Jesse Barnes");
MODULE_DESCRIPTION("DRM KMS helper");
MODULE_LICENSE("GPL and additional rights");

/**
 * drm_helper_move_panel_connectors_to_head() - move panels to the front in the
 * 						connector list
 * @dev: drm device to operate on
 *
 * Some userspace presumes that the first connected connector is the main
 * display, where it's supposed to display e.g. the login screen. For
 * laptops, this should be the main panel. Use this function to sort all
 * (eDP/LVDS) panels to the front of the connector list, instead of
 * painstakingly trying to initialize them in the right order.
 */
void drm_helper_move_panel_connectors_to_head(struct drm_device *dev)
{
	struct drm_connector *connector, *tmp;
	struct list_head panel_list;

	INIT_LIST_HEAD(&panel_list);

	list_for_each_entry_safe(connector, tmp,
				 &dev->mode_config.connector_list, head) {
		if (connector->connector_type == DRM_MODE_CONNECTOR_LVDS ||
		    connector->connector_type == DRM_MODE_CONNECTOR_eDP)
			list_move_tail(&connector->head, &panel_list);
	}

	list_splice(&panel_list, &dev->mode_config.connector_list);
}
EXPORT_SYMBOL(drm_helper_move_panel_connectors_to_head);

/**
 * drm_helper_encoder_in_use - check if a given encoder is in use
 * @encoder: encoder to check
 *
 * Checks whether @encoder is with the current mode setting output configuration
 * in use by any connector. This doesn't mean that it is actually enabled since
 * the DPMS state is tracked separately.
 *
 * Returns:
 * True if @encoder is used, false otherwise.
 */
bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
{
	struct drm_connector *connector;
	struct drm_device *dev = encoder->dev;

	/*
	 * We can expect this mutex to be locked if we are not panicking.
	 * Locking is currently fubar in the panic handler.
	 */
	if (!oops_in_progress) {
		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
	}

	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
		if (connector->encoder == encoder)
			return true;
	return false;
}
EXPORT_SYMBOL(drm_helper_encoder_in_use);

/**
 * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 * @crtc: CRTC to check
 *
 * Checks whether @crtc is with the current mode setting output configuration
 * in use by any connector. This doesn't mean that it is actually enabled since
 * the DPMS state is tracked separately.
 *
 * Returns:
 * True if @crtc is used, false otherwise.
 */
bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
{
	struct drm_encoder *encoder;
	struct drm_device *dev = crtc->dev;

	/*
	 * We can expect this mutex to be locked if we are not panicking.
	 * Locking is currently fubar in the panic handler.
	 */
	if (!oops_in_progress)
		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));

	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head)
		if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
			return true;
	return false;
}
EXPORT_SYMBOL(drm_helper_crtc_in_use);

static void
drm_encoder_disable(struct drm_encoder *encoder)
{
	const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;

	drm_bridge_disable(encoder->bridge);

	if (encoder_funcs->disable)
		(*encoder_funcs->disable)(encoder);
	else
		(*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);

	drm_bridge_post_disable(encoder->bridge);
}

static void __drm_helper_disable_unused_functions(struct drm_device *dev)
{
	struct drm_encoder *encoder;
	struct drm_crtc *crtc;

	drm_warn_on_modeset_not_all_locked(dev);

	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
		if (!drm_helper_encoder_in_use(encoder)) {
			drm_encoder_disable(encoder);
			/* disconnect encoder from any connector */
			encoder->crtc = NULL;
		}
	}

	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
		const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
		crtc->enabled = drm_helper_crtc_in_use(crtc);
		if (!crtc->enabled) {
			if (crtc_funcs->disable)
				(*crtc_funcs->disable)(crtc);
			else
				(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
			crtc->primary->fb = NULL;
		}
	}
}

/**
 * drm_helper_disable_unused_functions - disable unused objects
 * @dev: DRM device
 *
 * This function walks through the entire mode setting configuration of @dev. It
 * will remove any crtc links of unused encoders and encoder links of
 * disconnected connectors. Then it will disable all unused encoders and crtcs
 * either by calling their disable callback if available or by calling their
 * dpms callback with DRM_MODE_DPMS_OFF.
 */
void drm_helper_disable_unused_functions(struct drm_device *dev)
{
	drm_modeset_lock_all(dev);
	__drm_helper_disable_unused_functions(dev);
	drm_modeset_unlock_all(dev);
}
EXPORT_SYMBOL(drm_helper_disable_unused_functions);

/*
 * Check the CRTC we're going to map each output to vs. its current
 * CRTC.  If they don't match, we have to disable the output and the CRTC
 * since the driver will have to re-route things.
 */
static void
drm_crtc_prepare_encoders(struct drm_device *dev)
{
	const struct drm_encoder_helper_funcs *encoder_funcs;
	struct drm_encoder *encoder;

	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
		encoder_funcs = encoder->helper_private;
		/* Disable unused encoders */
		if (encoder->crtc == NULL)
			drm_encoder_disable(encoder);
		/* Disable encoders whose CRTC is about to change */
		if (encoder_funcs->get_crtc &&
		    encoder->crtc != (*encoder_funcs->get_crtc)(encoder))
			drm_encoder_disable(encoder);
	}
}

/**
 * drm_crtc_helper_set_mode - internal helper to set a mode
 * @crtc: CRTC to program
 * @mode: mode to use
 * @x: horizontal offset into the surface
 * @y: vertical offset into the surface
 * @old_fb: old framebuffer, for cleanup
 *
 * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
 * to fixup or reject the mode prior to trying to set it. This is an internal
 * helper that drivers could e.g. use to update properties that require the
 * entire output pipe to be disabled and re-enabled in a new configuration. For
 * example for changing whether audio is enabled on a hdmi link or for changing
 * panel fitter or dither attributes. It is also called by the
 * drm_crtc_helper_set_config() helper function to drive the mode setting
 * sequence.
 *
 * Returns:
 * True if the mode was set successfully, false otherwise.
 */
bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
			      struct drm_display_mode *mode,
			      int x, int y,
			      struct drm_framebuffer *old_fb)
{
	struct drm_device *dev = crtc->dev;
	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
	const struct drm_encoder_helper_funcs *encoder_funcs;
	int saved_x, saved_y;
	bool saved_enabled;
	struct drm_encoder *encoder;
	bool ret = true;

	drm_warn_on_modeset_not_all_locked(dev);

	saved_enabled = crtc->enabled;
	crtc->enabled = drm_helper_crtc_in_use(crtc);
	if (!crtc->enabled)
		return true;

	adjusted_mode = drm_mode_duplicate(dev, mode);
	if (!adjusted_mode) {
		crtc->enabled = saved_enabled;
		return false;
	}

	saved_mode = crtc->mode;
	saved_hwmode = crtc->hwmode;
	saved_x = crtc->x;
	saved_y = crtc->y;

	/* Update crtc values up front so the driver can rely on them for mode
	 * setting.
	 */
	crtc->mode = *mode;
	crtc->x = x;
	crtc->y = y;

	/* Pass our mode to the connectors and the CRTC to give them a chance to
	 * adjust it according to limitations or connector properties, and also
	 * a chance to reject the mode entirely.
	 */
	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {

		if (encoder->crtc != crtc)
			continue;

		ret = drm_bridge_mode_fixup(encoder->bridge,
			mode, adjusted_mode);
		if (!ret) {
			DRM_DEBUG_KMS("Bridge fixup failed\n");
			goto done;
		}

		encoder_funcs = encoder->helper_private;
		if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
						      adjusted_mode))) {
			DRM_DEBUG_KMS("Encoder fixup failed\n");
			goto done;
		}
	}

	if (!(ret = crtc_funcs->mode_fixup(crtc, mode, adjusted_mode))) {
		DRM_DEBUG_KMS("CRTC fixup failed\n");
		goto done;
	}
	DRM_DEBUG_KMS("[CRTC:%d]\n", crtc->base.id);

	crtc->hwmode = *adjusted_mode;

	/* Prepare the encoders and CRTCs before setting the mode. */
	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {

		if (encoder->crtc != crtc)
			continue;

		drm_bridge_disable(encoder->bridge);

		encoder_funcs = encoder->helper_private;
		/* Disable the encoders as the first thing we do. */
		encoder_funcs->prepare(encoder);

		drm_bridge_post_disable(encoder->bridge);
	}

	drm_crtc_prepare_encoders(dev);

	crtc_funcs->prepare(crtc);

	/* Set up the DPLL and any encoders state that needs to adjust or depend
	 * on the DPLL.
	 */
	ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
	if (!ret)
	    goto done;

	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {

		if (encoder->crtc != crtc)
			continue;

		DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%d:%s]\n",
			encoder->base.id, encoder->name,
			mode->base.id, mode->name);
		encoder_funcs = encoder->helper_private;
		encoder_funcs->mode_set(encoder, mode, adjusted_mode);

		drm_bridge_mode_set(encoder->bridge, mode, adjusted_mode);
	}

	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
	crtc_funcs->commit(crtc);

	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {

		if (encoder->crtc != crtc)
			continue;

		drm_bridge_pre_enable(encoder->bridge);

		encoder_funcs = encoder->helper_private;
		encoder_funcs->commit(encoder);

		drm_bridge_enable(encoder->bridge);
	}

	/* Calculate and store various constants which
	 * are later needed by vblank and swap-completion
	 * timestamping. They are derived from true hwmode.
	 */
	drm_calc_timestamping_constants(crtc, &crtc->hwmode);

	/* FIXME: add subpixel order */
done:
	drm_mode_destroy(dev, adjusted_mode);
	if (!ret) {
		crtc->enabled = saved_enabled;
		crtc->mode = saved_mode;
		crtc->hwmode = saved_hwmode;
		crtc->x = saved_x;
		crtc->y = saved_y;
	}

	return ret;
}
EXPORT_SYMBOL(drm_crtc_helper_set_mode);

static void
drm_crtc_helper_disable(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;
	struct drm_connector *connector;
	struct drm_encoder *encoder;

	/* Decouple all encoders and their attached connectors from this crtc */
	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
		if (encoder->crtc != crtc)
			continue;

		list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
			if (connector->encoder != encoder)
				continue;

			connector->encoder = NULL;

			/*
			 * drm_helper_disable_unused_functions() ought to be
			 * doing this, but since we've decoupled the encoder
			 * from the connector above, the required connection
			 * between them is henceforth no longer available.
			 */
			connector->dpms = DRM_MODE_DPMS_OFF;
		}
	}

	__drm_helper_disable_unused_functions(dev);
}

/**
 * drm_crtc_helper_set_config - set a new config from userspace
 * @set: mode set configuration
 *
 * Setup a new configuration, provided by the upper layers (either an ioctl call
 * from userspace or internally e.g. from the fbdev support code) in @set, and
 * enable it. This is the main helper functions for drivers that implement
 * kernel mode setting with the crtc helper functions and the assorted
 * ->prepare(), ->modeset() and ->commit() helper callbacks.
 *
 * Returns:
 * Returns 0 on success, negative errno numbers on failure.
 */
int drm_crtc_helper_set_config(struct drm_mode_set *set)
{
	struct drm_device *dev;
	struct drm_crtc *new_crtc;
	struct drm_encoder *save_encoders, *new_encoder, *encoder;
	bool mode_changed = false; /* if true do a full mode set */
	bool fb_changed = false; /* if true and !mode_changed just do a flip */
	struct drm_connector *save_connectors, *connector;
	int count = 0, ro, fail = 0;
	const struct drm_crtc_helper_funcs *crtc_funcs;
	struct drm_mode_set save_set;
	int ret;
	int i;

	DRM_DEBUG_KMS("\n");

	BUG_ON(!set);
	BUG_ON(!set->crtc);
	BUG_ON(!set->crtc->helper_private);

	/* Enforce sane interface api - has been abused by the fb helper. */
	BUG_ON(!set->mode && set->fb);
	BUG_ON(set->fb && set->num_connectors == 0);

	crtc_funcs = set->crtc->helper_private;

	if (!set->mode)
		set->fb = NULL;

	if (set->fb) {
		DRM_DEBUG_KMS("[CRTC:%d] [FB:%d] #connectors=%d (x y) (%i %i)\n",
				set->crtc->base.id, set->fb->base.id,
				(int)set->num_connectors, set->x, set->y);
	} else {
		DRM_DEBUG_KMS("[CRTC:%d] [NOFB]\n", set->crtc->base.id);
		drm_crtc_helper_disable(set->crtc);
		return 0;
	}

	dev = set->crtc->dev;

	drm_warn_on_modeset_not_all_locked(dev);

	/*
	 * Allocate space for the backup of all (non-pointer) encoder and
	 * connector data.
	 */
	save_encoders = kzalloc(dev->mode_config.num_encoder *
				sizeof(struct drm_encoder), GFP_KERNEL);
	if (!save_encoders)
		return -ENOMEM;

	save_connectors = kzalloc(dev->mode_config.num_connector *
				sizeof(struct drm_connector), GFP_KERNEL);
	if (!save_connectors) {
		kfree(save_encoders);
		return -ENOMEM;
	}

	/*
	 * Copy data. Note that driver private data is not affected.
	 * Should anything bad happen only the expected state is
	 * restored, not the drivers personal bookkeeping.
	 */
	count = 0;
	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
		save_encoders[count++] = *encoder;
	}

	count = 0;
	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
		save_connectors[count++] = *connector;
	}

	save_set.crtc = set->crtc;
	save_set.mode = &set->crtc->mode;
	save_set.x = set->crtc->x;
	save_set.y = set->crtc->y;
	save_set.fb = set->crtc->primary->fb;

	/* We should be able to check here if the fb has the same properties
	 * and then just flip_or_move it */
	if (set->crtc->primary->fb != set->fb) {
		/* If we have no fb then treat it as a full mode set */
		if (set->crtc->primary->fb == NULL) {
			DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
			mode_changed = true;
		} else if (set->fb == NULL) {
			mode_changed = true;
		} else if (set->fb->pixel_format !=
			   set->crtc->primary->fb->pixel_format) {
			mode_changed = true;
		} else
			fb_changed = true;
	}

	if (set->x != set->crtc->x || set->y != set->crtc->y)
		fb_changed = true;

	if (set->mode && !drm_mode_equal(set->mode, &set->crtc->mode)) {
		DRM_DEBUG_KMS("modes are different, full mode set\n");
		drm_mode_debug_printmodeline(&set->crtc->mode);
		drm_mode_debug_printmodeline(set->mode);
		mode_changed = true;
	}

	/* a) traverse passed in connector list and get encoders for them */
	count = 0;
	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
		const struct drm_connector_helper_funcs *connector_funcs =
			connector->helper_private;
		new_encoder = connector->encoder;
		for (ro = 0; ro < set->num_connectors; ro++) {
			if (set->connectors[ro] == connector) {
				new_encoder = connector_funcs->best_encoder(connector);
				/* if we can't get an encoder for a connector
				   we are setting now - then fail */
				if (new_encoder == NULL)
					/* don't break so fail path works correct */
					fail = 1;

				if (connector->dpms != DRM_MODE_DPMS_ON) {
					DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
					mode_changed = true;
				}

				break;
			}
		}

		if (new_encoder != connector->encoder) {
			DRM_DEBUG_KMS("encoder changed, full mode switch\n");
			mode_changed = true;
			/* If the encoder is reused for another connector, then
			 * the appropriate crtc will be set later.
			 */
			if (connector->encoder)
				connector->encoder->crtc = NULL;
			connector->encoder = new_encoder;
		}
	}

	if (fail) {
		ret = -EINVAL;
		goto fail;
	}

	count = 0;
	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
		if (!connector->encoder)
			continue;

		if (connector->encoder->crtc == set->crtc)
			new_crtc = NULL;
		else
			new_crtc = connector->encoder->crtc;

		for (ro = 0; ro < set->num_connectors; ro++) {
			if (set->connectors[ro] == connector)
				new_crtc = set->crtc;
		}

		/* Make sure the new CRTC will work with the encoder */
		if (new_crtc &&
		    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
			ret = -EINVAL;
			goto fail;
		}
		if (new_crtc != connector->encoder->crtc) {
			DRM_DEBUG_KMS("crtc changed, full mode switch\n");
			mode_changed = true;
			connector->encoder->crtc = new_crtc;
		}
		if (new_crtc) {
			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d]\n",
				connector->base.id, connector->name,
				new_crtc->base.id);
		} else {
			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
				connector->base.id, connector->name);
		}
	}

	/* mode_set_base is not a required function */
	if (fb_changed && !crtc_funcs->mode_set_base)
		mode_changed = true;

	if (mode_changed) {
		if (drm_helper_crtc_in_use(set->crtc)) {
			DRM_DEBUG_KMS("attempting to set mode from"
					" userspace\n");
			drm_mode_debug_printmodeline(set->mode);
			set->crtc->primary->fb = set->fb;
			if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
						      set->x, set->y,
						      save_set.fb)) {
				DRM_ERROR("failed to set mode on [CRTC:%d]\n",
					  set->crtc->base.id);
				set->crtc->primary->fb = save_set.fb;
				ret = -EINVAL;
				goto fail;
			}
			DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
			for (i = 0; i < set->num_connectors; i++) {
				DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
					      set->connectors[i]->name);
				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
			}
		}
		__drm_helper_disable_unused_functions(dev);
	} else if (fb_changed) {
		set->crtc->x = set->x;
		set->crtc->y = set->y;
		set->crtc->primary->fb = set->fb;
		ret = crtc_funcs->mode_set_base(set->crtc,
						set->x, set->y, save_set.fb);
		if (ret != 0) {
			set->crtc->x = save_set.x;
			set->crtc->y = save_set.y;
			set->crtc->primary->fb = save_set.fb;
			goto fail;
		}
	}

	kfree(save_connectors);
	kfree(save_encoders);
	return 0;

fail:
	/* Restore all previous data. */
	count = 0;
	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
		*encoder = save_encoders[count++];
	}

	count = 0;
	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
		*connector = save_connectors[count++];
	}

	/* Try to restore the config */
	if (mode_changed &&
	    !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
				      save_set.y, save_set.fb))
		DRM_ERROR("failed to restore config after modeset failure\n");

	kfree(save_connectors);
	kfree(save_encoders);
	return ret;
}
EXPORT_SYMBOL(drm_crtc_helper_set_config);

static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
{
	int dpms = DRM_MODE_DPMS_OFF;
	struct drm_connector *connector;
	struct drm_device *dev = encoder->dev;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
		if (connector->encoder == encoder)
			if (connector->dpms < dpms)
				dpms = connector->dpms;
	return dpms;
}

/* Helper which handles bridge ordering around encoder dpms */
static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
{
	struct drm_bridge *bridge = encoder->bridge;
	const struct drm_encoder_helper_funcs *encoder_funcs;

	if (mode == DRM_MODE_DPMS_ON)
		drm_bridge_pre_enable(bridge);
	else
		drm_bridge_disable(bridge);

	encoder_funcs = encoder->helper_private;
	if (encoder_funcs->dpms)
		encoder_funcs->dpms(encoder, mode);

	if (mode == DRM_MODE_DPMS_ON)
		drm_bridge_enable(bridge);
	else
		drm_bridge_post_disable(bridge);
}

static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
{
	int dpms = DRM_MODE_DPMS_OFF;
	struct drm_connector *connector;
	struct drm_device *dev = crtc->dev;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
		if (connector->encoder && connector->encoder->crtc == crtc)
			if (connector->dpms < dpms)
				dpms = connector->dpms;
	return dpms;
}

/**
 * drm_helper_connector_dpms() - connector dpms helper implementation
 * @connector: affected connector
 * @mode: DPMS mode
 *
 * This is the main helper function provided by the crtc helper framework for
 * implementing the DPMS connector attribute. It computes the new desired DPMS
 * state for all encoders and crtcs in the output mesh and calls the ->dpms()
 * callback provided by the driver appropriately.
 */
void drm_helper_connector_dpms(struct drm_connector *connector, int mode)
{
	struct drm_encoder *encoder = connector->encoder;
	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;

	if (mode == connector->dpms)
		return;

	old_dpms = connector->dpms;
	connector->dpms = mode;

	if (encoder)
		encoder_dpms = drm_helper_choose_encoder_dpms(encoder);

	/* from off to on, do crtc then encoder */
	if (mode < old_dpms) {
		if (crtc) {
			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
			if (crtc_funcs->dpms)
				(*crtc_funcs->dpms) (crtc,
						     drm_helper_choose_crtc_dpms(crtc));
		}
		if (encoder)
			drm_helper_encoder_dpms(encoder, encoder_dpms);
	}

	/* from on to off, do encoder then crtc */
	if (mode > old_dpms) {
		if (encoder)
			drm_helper_encoder_dpms(encoder, encoder_dpms);
		if (crtc) {
			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
			if (crtc_funcs->dpms)
				(*crtc_funcs->dpms) (crtc,
						     drm_helper_choose_crtc_dpms(crtc));
		}
	}

	return;
}
EXPORT_SYMBOL(drm_helper_connector_dpms);

/**
 * drm_helper_mode_fill_fb_struct - fill out framebuffer metadata
 * @fb: drm_framebuffer object to fill out
 * @mode_cmd: metadata from the userspace fb creation request
 *
 * This helper can be used in a drivers fb_create callback to pre-fill the fb's
 * metadata fields.
 */
void drm_helper_mode_fill_fb_struct(struct drm_framebuffer *fb,
				    struct drm_mode_fb_cmd2 *mode_cmd)
{
	int i;

	fb->width = mode_cmd->width;
	fb->height = mode_cmd->height;
	for (i = 0; i < 4; i++) {
		fb->pitches[i] = mode_cmd->pitches[i];
		fb->offsets[i] = mode_cmd->offsets[i];
		fb->modifier[i] = mode_cmd->modifier[i];
	}
	drm_fb_get_bpp_depth(mode_cmd->pixel_format, &fb->depth,
				    &fb->bits_per_pixel);
	fb->pixel_format = mode_cmd->pixel_format;
	fb->flags = mode_cmd->flags;
}
EXPORT_SYMBOL(drm_helper_mode_fill_fb_struct);

/**
 * drm_helper_resume_force_mode - force-restore mode setting configuration
 * @dev: drm_device which should be restored
 *
 * Drivers which use the mode setting helpers can use this function to
 * force-restore the mode setting configuration e.g. on resume or when something
 * else might have trampled over the hw state (like some overzealous old BIOSen
 * tended to do).
 *
 * This helper doesn't provide a error return value since restoring the old
 * config should never fail due to resource allocation issues since the driver
 * has successfully set the restored configuration already. Hence this should
 * boil down to the equivalent of a few dpms on calls, which also don't provide
 * an error code.
 *
 * Drivers where simply restoring an old configuration again might fail (e.g.
 * due to slight differences in allocating shared resources when the
 * configuration is restored in a different order than when userspace set it up)
 * need to use their own restore logic.
 */
void drm_helper_resume_force_mode(struct drm_device *dev)
{
	struct drm_crtc *crtc;
	struct drm_encoder *encoder;
	const struct drm_crtc_helper_funcs *crtc_funcs;
	int encoder_dpms;
	bool ret;

	drm_modeset_lock_all(dev);
	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

		if (!crtc->enabled)
			continue;

		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
					       crtc->x, crtc->y, crtc->primary->fb);

		/* Restoring the old config should never fail! */
		if (ret == false)
			DRM_ERROR("failed to set mode on crtc %p\n", crtc);

		/* Turn off outputs that were already powered off */
		if (drm_helper_choose_crtc_dpms(crtc)) {
			list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {

				if(encoder->crtc != crtc)
					continue;

				encoder_dpms = drm_helper_choose_encoder_dpms(
							encoder);

				drm_helper_encoder_dpms(encoder, encoder_dpms);
			}

			crtc_funcs = crtc->helper_private;
			if (crtc_funcs->dpms)
				(*crtc_funcs->dpms) (crtc,
						     drm_helper_choose_crtc_dpms(crtc));
		}
	}

	/* disable the unused connectors while restoring the modesetting */
	__drm_helper_disable_unused_functions(dev);
	drm_modeset_unlock_all(dev);
}
EXPORT_SYMBOL(drm_helper_resume_force_mode);

/**
 * drm_helper_crtc_mode_set - mode_set implementation for atomic plane helpers
 * @crtc: DRM CRTC
 * @mode: DRM display mode which userspace requested
 * @adjusted_mode: DRM display mode adjusted by ->mode_fixup callbacks
 * @x: x offset of the CRTC scanout area on the underlying framebuffer
 * @y: y offset of the CRTC scanout area on the underlying framebuffer
 * @old_fb: previous framebuffer
 *
 * This function implements a callback useable as the ->mode_set callback
 * required by the crtc helpers. Besides the atomic plane helper functions for
 * the primary plane the driver must also provide the ->mode_set_nofb callback
 * to set up the crtc.
 *
 * This is a transitional helper useful for converting drivers to the atomic
 * interfaces.
 */
int drm_helper_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *mode,
			     struct drm_display_mode *adjusted_mode, int x, int y,
			     struct drm_framebuffer *old_fb)
{
	struct drm_crtc_state *crtc_state;
	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
	int ret;

	if (crtc->funcs->atomic_duplicate_state)
		crtc_state = crtc->funcs->atomic_duplicate_state(crtc);
	else {
		crtc_state = kzalloc(sizeof(*crtc_state), GFP_KERNEL);
		if (!crtc_state)
			return -ENOMEM;
		if (crtc->state)
			__drm_atomic_helper_crtc_duplicate_state(crtc, crtc_state);
		else
			crtc_state->crtc = crtc;
	}

	crtc_state->planes_changed = true;
	crtc_state->mode_changed = true;
	ret = drm_atomic_set_mode_for_crtc(crtc_state, mode);
	if (ret)
		goto out;
	drm_mode_copy(&crtc_state->adjusted_mode, adjusted_mode);

	if (crtc_funcs->atomic_check) {
		ret = crtc_funcs->atomic_check(crtc, crtc_state);
		if (ret)
			goto out;
	}

	swap(crtc->state, crtc_state);

	crtc_funcs->mode_set_nofb(crtc);

	ret = drm_helper_crtc_mode_set_base(crtc, x, y, old_fb);

out:
	if (crtc->funcs->atomic_destroy_state)
		crtc->funcs->atomic_destroy_state(crtc, crtc_state);
	else {
		__drm_atomic_helper_crtc_destroy_state(crtc, crtc_state);
		kfree(crtc_state);
	}

	return ret;
}
EXPORT_SYMBOL(drm_helper_crtc_mode_set);

/**
 * drm_helper_crtc_mode_set_base - mode_set_base implementation for atomic plane helpers
 * @crtc: DRM CRTC
 * @x: x offset of the CRTC scanout area on the underlying framebuffer
 * @y: y offset of the CRTC scanout area on the underlying framebuffer
 * @old_fb: previous framebuffer
 *
 * This function implements a callback useable as the ->mode_set_base used
 * required by the crtc helpers. The driver must provide the atomic plane helper
 * functions for the primary plane.
 *
 * This is a transitional helper useful for converting drivers to the atomic
 * interfaces.
 */
int drm_helper_crtc_mode_set_base(struct drm_crtc *crtc, int x, int y,
				  struct drm_framebuffer *old_fb)
{
	struct drm_plane_state *plane_state;
	struct drm_plane *plane = crtc->primary;

	if (plane->funcs->atomic_duplicate_state)
		plane_state = plane->funcs->atomic_duplicate_state(plane);
	else if (plane->state)
		plane_state = drm_atomic_helper_plane_duplicate_state(plane);
	else
		plane_state = kzalloc(sizeof(*plane_state), GFP_KERNEL);
	if (!plane_state)
		return -ENOMEM;
	plane_state->plane = plane;

	plane_state->crtc = crtc;
	drm_atomic_set_fb_for_plane(plane_state, crtc->primary->fb);
	plane_state->crtc_x = 0;
	plane_state->crtc_y = 0;
	plane_state->crtc_h = crtc->mode.vdisplay;
	plane_state->crtc_w = crtc->mode.hdisplay;
	plane_state->src_x = x << 16;
	plane_state->src_y = y << 16;
	plane_state->src_h = crtc->mode.vdisplay << 16;
	plane_state->src_w = crtc->mode.hdisplay << 16;

	return drm_plane_helper_commit(plane, plane_state, old_fb);
}
EXPORT_SYMBOL(drm_helper_crtc_mode_set_base);