summaryrefslogtreecommitdiffstats
path: root/include/drm/drm_connector.h
blob: 91a877fa00cb59161125a711515931e49b040e53 (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
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
/*
 * Copyright (c) 2016 Intel Corporation
 *
 * 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.
 */

#ifndef __DRM_CONNECTOR_H__
#define __DRM_CONNECTOR_H__

#include <linux/list.h>
#include <linux/llist.h>
#include <linux/ctype.h>
#include <linux/hdmi.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_util.h>

#include <uapi/drm/drm_mode.h>

struct drm_connector_helper_funcs;
struct drm_modeset_acquire_ctx;
struct drm_device;
struct drm_crtc;
struct drm_encoder;
struct drm_property;
struct drm_property_blob;
struct drm_printer;
struct edid;

enum drm_connector_force {
	DRM_FORCE_UNSPECIFIED,
	DRM_FORCE_OFF,
	DRM_FORCE_ON,         /* force on analog part normally */
	DRM_FORCE_ON_DIGITAL, /* for DVI-I use digital connector */
};

/**
 * enum drm_connector_status - status for a &drm_connector
 *
 * This enum is used to track the connector status. There are no separate
 * #defines for the uapi!
 */
enum drm_connector_status {
	/**
	 * @connector_status_connected: The connector is definitely connected to
	 * a sink device, and can be enabled.
	 */
	connector_status_connected = 1,
	/**
	 * @connector_status_disconnected: The connector isn't connected to a
	 * sink device which can be autodetect. For digital outputs like DP or
	 * HDMI (which can be realiable probed) this means there's really
	 * nothing there. It is driver-dependent whether a connector with this
	 * status can be lit up or not.
	 */
	connector_status_disconnected = 2,
	/**
	 * @connector_status_unknown: The connector's status could not be
	 * reliably detected. This happens when probing would either cause
	 * flicker (like load-detection when the connector is in use), or when a
	 * hardware resource isn't available (like when load-detection needs a
	 * free CRTC). It should be possible to light up the connector with one
	 * of the listed fallback modes. For default configuration userspace
	 * should only try to light up connectors with unknown status when
	 * there's not connector with @connector_status_connected.
	 */
	connector_status_unknown = 3,
};

enum subpixel_order {
	SubPixelUnknown = 0,
	SubPixelHorizontalRGB,
	SubPixelHorizontalBGR,
	SubPixelVerticalRGB,
	SubPixelVerticalBGR,
	SubPixelNone,

};

/**
 * struct drm_scrambling: sink's scrambling support.
 */
struct drm_scrambling {
	/**
	 * @supported: scrambling supported for rates > 340 Mhz.
	 */
	bool supported;
	/**
	 * @low_rates: scrambling supported for rates <= 340 Mhz.
	 */
	bool low_rates;
};

/*
 * struct drm_scdc - Information about scdc capabilities of a HDMI 2.0 sink
 *
 * Provides SCDC register support and capabilities related information on a
 * HDMI 2.0 sink. In case of a HDMI 1.4 sink, all parameter must be 0.
 */
struct drm_scdc {
	/**
	 * @supported: status control & data channel present.
	 */
	bool supported;
	/**
	 * @read_request: sink is capable of generating scdc read request.
	 */
	bool read_request;
	/**
	 * @scrambling: sink's scrambling capabilities
	 */
	struct drm_scrambling scrambling;
};


/**
 * struct drm_hdmi_info - runtime information about the connected HDMI sink
 *
 * Describes if a given display supports advanced HDMI 2.0 features.
 * This information is available in CEA-861-F extension blocks (like HF-VSDB).
 */
struct drm_hdmi_info {
	/** @scdc: sink's scdc support and capabilities */
	struct drm_scdc scdc;

	/**
	 * @y420_vdb_modes: bitmap of modes which can support ycbcr420
	 * output only (not normal RGB/YCBCR444/422 outputs). There are total
	 * 107 VICs defined by CEA-861-F spec, so the size is 128 bits to map
	 * upto 128 VICs;
	 */
	unsigned long y420_vdb_modes[BITS_TO_LONGS(128)];

	/**
	 * @y420_cmdb_modes: bitmap of modes which can support ycbcr420
	 * output also, along with normal HDMI outputs. There are total 107
	 * VICs defined by CEA-861-F spec, so the size is 128 bits to map upto
	 * 128 VICs;
	 */
	unsigned long y420_cmdb_modes[BITS_TO_LONGS(128)];

	/** @y420_cmdb_map: bitmap of SVD index, to extraxt vcb modes */
	u64 y420_cmdb_map;

	/** @y420_dc_modes: bitmap of deep color support index */
	u8 y420_dc_modes;
};

/**
 * enum drm_link_status - connector's link_status property value
 *
 * This enum is used as the connector's link status property value.
 * It is set to the values defined in uapi.
 *
 * @DRM_LINK_STATUS_GOOD: DP Link is Good as a result of successful
 *                        link training
 * @DRM_LINK_STATUS_BAD: DP Link is BAD as a result of link training
 *                       failure
 */
enum drm_link_status {
	DRM_LINK_STATUS_GOOD = DRM_MODE_LINK_STATUS_GOOD,
	DRM_LINK_STATUS_BAD = DRM_MODE_LINK_STATUS_BAD,
};

/**
 * enum drm_panel_orientation - panel_orientation info for &drm_display_info
 *
 * This enum is used to track the (LCD) panel orientation. There are no
 * separate #defines for the uapi!
 *
 * @DRM_MODE_PANEL_ORIENTATION_UNKNOWN: The drm driver has not provided any
 *					panel orientation information (normal
 *					for non panels) in this case the "panel
 *					orientation" connector prop will not be
 *					attached.
 * @DRM_MODE_PANEL_ORIENTATION_NORMAL:	The top side of the panel matches the
 *					top side of the device's casing.
 * @DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP: The top side of the panel matches the
 *					bottom side of the device's casing, iow
 *					the panel is mounted upside-down.
 * @DRM_MODE_PANEL_ORIENTATION_LEFT_UP:	The left side of the panel matches the
 *					top side of the device's casing.
 * @DRM_MODE_PANEL_ORIENTATION_RIGHT_UP: The right side of the panel matches the
 *					top side of the device's casing.
 */
enum drm_panel_orientation {
	DRM_MODE_PANEL_ORIENTATION_UNKNOWN = -1,
	DRM_MODE_PANEL_ORIENTATION_NORMAL = 0,
	DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP,
	DRM_MODE_PANEL_ORIENTATION_LEFT_UP,
	DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
};

/**
 * struct drm_display_info - runtime data about the connected sink
 *
 * Describes a given display (e.g. CRT or flat panel) and its limitations. For
 * fixed display sinks like built-in panels there's not much difference between
 * this and &struct drm_connector. But for sinks with a real cable this
 * structure is meant to describe all the things at the other end of the cable.
 *
 * For sinks which provide an EDID this can be filled out by calling
 * drm_add_edid_modes().
 */
struct drm_display_info {
	/**
	 * @name: Name of the display.
	 */
	char name[DRM_DISPLAY_INFO_LEN];

	/**
	 * @width_mm: Physical width in mm.
	 */
        unsigned int width_mm;
	/**
	 * @height_mm: Physical height in mm.
	 */
	unsigned int height_mm;

	/**
	 * @pixel_clock: Maximum pixel clock supported by the sink, in units of
	 * 100Hz. This mismatches the clock in &drm_display_mode (which is in
	 * kHZ), because that's what the EDID uses as base unit.
	 */
	unsigned int pixel_clock;
	/**
	 * @bpc: Maximum bits per color channel. Used by HDMI and DP outputs.
	 */
	unsigned int bpc;

	/**
	 * @subpixel_order: Subpixel order of LCD panels.
	 */
	enum subpixel_order subpixel_order;

#define DRM_COLOR_FORMAT_RGB444		(1<<0)
#define DRM_COLOR_FORMAT_YCRCB444	(1<<1)
#define DRM_COLOR_FORMAT_YCRCB422	(1<<2)
#define DRM_COLOR_FORMAT_YCRCB420	(1<<3)

	/**
	 * @panel_orientation: Read only connector property for built-in panels,
	 * indicating the orientation of the panel vs the device's casing.
	 * drm_connector_init() sets this to DRM_MODE_PANEL_ORIENTATION_UNKNOWN.
	 * When not UNKNOWN this gets used by the drm_fb_helpers to rotate the
	 * fb to compensate and gets exported as prop to userspace.
	 */
	int panel_orientation;

	/**
	 * @color_formats: HDMI Color formats, selects between RGB and YCrCb
	 * modes. Used DRM_COLOR_FORMAT\_ defines, which are _not_ the same ones
	 * as used to describe the pixel format in framebuffers, and also don't
	 * match the formats in @bus_formats which are shared with v4l.
	 */
	u32 color_formats;

	/**
	 * @bus_formats: Pixel data format on the wire, somewhat redundant with
	 * @color_formats. Array of size @num_bus_formats encoded using
	 * MEDIA_BUS_FMT\_ defines shared with v4l and media drivers.
	 */
	const u32 *bus_formats;
	/**
	 * @num_bus_formats: Size of @bus_formats array.
	 */
	unsigned int num_bus_formats;

#define DRM_BUS_FLAG_DE_LOW		(1<<0)
#define DRM_BUS_FLAG_DE_HIGH		(1<<1)
/* drive data on pos. edge */
#define DRM_BUS_FLAG_PIXDATA_POSEDGE	(1<<2)
/* drive data on neg. edge */
#define DRM_BUS_FLAG_PIXDATA_NEGEDGE	(1<<3)
/* data is transmitted MSB to LSB on the bus */
#define DRM_BUS_FLAG_DATA_MSB_TO_LSB	(1<<4)
/* data is transmitted LSB to MSB on the bus */
#define DRM_BUS_FLAG_DATA_LSB_TO_MSB	(1<<5)
/* drive sync on pos. edge */
#define DRM_BUS_FLAG_SYNC_POSEDGE	(1<<6)
/* drive sync on neg. edge */
#define DRM_BUS_FLAG_SYNC_NEGEDGE	(1<<7)

	/**
	 * @bus_flags: Additional information (like pixel signal polarity) for
	 * the pixel data on the bus, using DRM_BUS_FLAGS\_ defines.
	 */
	u32 bus_flags;

	/**
	 * @max_tmds_clock: Maximum TMDS clock rate supported by the
	 * sink in kHz. 0 means undefined.
	 */
	int max_tmds_clock;

	/**
	 * @dvi_dual: Dual-link DVI sink?
	 */
	bool dvi_dual;

	/**
	 * @has_hdmi_infoframe: Does the sink support the HDMI infoframe?
	 */
	bool has_hdmi_infoframe;

	/**
	 * @edid_hdmi_dc_modes: Mask of supported hdmi deep color modes. Even
	 * more stuff redundant with @bus_formats.
	 */
	u8 edid_hdmi_dc_modes;

	/**
	 * @cea_rev: CEA revision of the HDMI sink.
	 */
	u8 cea_rev;

	/**
	 * @hdmi: advance features of a HDMI sink.
	 */
	struct drm_hdmi_info hdmi;

	/**
	 * @non_desktop: Non desktop display (HMD).
	 */
	bool non_desktop;
};

int drm_display_info_set_bus_formats(struct drm_display_info *info,
				     const u32 *formats,
				     unsigned int num_formats);

/**
 * struct drm_tv_connector_state - TV connector related states
 * @subconnector: selected subconnector
 * @margins: margins
 * @margins.left: left margin
 * @margins.right: right margin
 * @margins.top: top margin
 * @margins.bottom: bottom margin
 * @mode: TV mode
 * @brightness: brightness in percent
 * @contrast: contrast in percent
 * @flicker_reduction: flicker reduction in percent
 * @overscan: overscan in percent
 * @saturation: saturation in percent
 * @hue: hue in percent
 */
struct drm_tv_connector_state {
	enum drm_mode_subconnector subconnector;
	struct {
		unsigned int left;
		unsigned int right;
		unsigned int top;
		unsigned int bottom;
	} margins;
	unsigned int mode;
	unsigned int brightness;
	unsigned int contrast;
	unsigned int flicker_reduction;
	unsigned int overscan;
	unsigned int saturation;
	unsigned int hue;
};

/**
 * struct drm_connector_state - mutable connector state
 */
struct drm_connector_state {
	/** @connector: backpointer to the connector */
	struct drm_connector *connector;

	/**
	 * @crtc: CRTC to connect connector to, NULL if disabled.
	 *
	 * Do not change this directly, use drm_atomic_set_crtc_for_connector()
	 * instead.
	 */
	struct drm_crtc *crtc;

	/**
	 * @best_encoder:
	 *
	 * Used by the atomic helpers to select the encoder, through the
	 * &drm_connector_helper_funcs.atomic_best_encoder or
	 * &drm_connector_helper_funcs.best_encoder callbacks.
	 */
	struct drm_encoder *best_encoder;

	/**
	 * @link_status: Connector link_status to keep track of whether link is
	 * GOOD or BAD to notify userspace if retraining is necessary.
	 */
	enum drm_link_status link_status;

	/** @state: backpointer to global drm_atomic_state */
	struct drm_atomic_state *state;

	/**
	 * @commit: Tracks the pending commit to prevent use-after-free conditions.
	 *
	 * Is only set when @crtc is NULL.
	 */
	struct drm_crtc_commit *commit;

	/** @tv: TV connector state */
	struct drm_tv_connector_state tv;

	/**
	 * @picture_aspect_ratio: Connector property to control the
	 * HDMI infoframe aspect ratio setting.
	 *
	 * The %DRM_MODE_PICTURE_ASPECT_\* values much match the
	 * values for &enum hdmi_picture_aspect
	 */
	enum hdmi_picture_aspect picture_aspect_ratio;

	/**
	 * @content_type: Connector property to control the
	 * HDMI infoframe content type setting.
	 * The %DRM_MODE_CONTENT_TYPE_\* values much
	 * match the values.
	 */
	unsigned int content_type;

	/**
	 * @scaling_mode: Connector property to control the
	 * upscaling, mostly used for built-in panels.
	 */
	unsigned int scaling_mode;

	/**
	 * @content_protection: Connector property to request content
	 * protection. This is most commonly used for HDCP.
	 */
	unsigned int content_protection;

	/**
	 * @writeback_job: Writeback job for writeback connectors
	 *
	 * Holds the framebuffer and out-fence for a writeback connector. As
	 * the writeback completion may be asynchronous to the normal commit
	 * cycle, the writeback job lifetime is managed separately from the
	 * normal atomic state by this object.
	 *
	 * See also: drm_writeback_queue_job() and
	 * drm_writeback_signal_completion()
	 */
	struct drm_writeback_job *writeback_job;
};

/**
 * struct drm_connector_funcs - control connectors on a given device
 *
 * Each CRTC may have one or more connectors attached to it.  The functions
 * below allow the core DRM code to control connectors, enumerate available modes,
 * etc.
 */
struct drm_connector_funcs {
	/**
	 * @dpms:
	 *
	 * Legacy entry point to set the per-connector DPMS state. Legacy DPMS
	 * is exposed as a standard property on the connector, but diverted to
	 * this callback in the drm core. Note that atomic drivers don't
	 * implement the 4 level DPMS support on the connector any more, but
	 * instead only have an on/off "ACTIVE" property on the CRTC object.
	 *
	 * This hook is not used by atomic drivers, remapping of the legacy DPMS
	 * property is entirely handled in the DRM core.
	 *
	 * RETURNS:
	 *
	 * 0 on success or a negative error code on failure.
	 */
	int (*dpms)(struct drm_connector *connector, int mode);

	/**
	 * @reset:
	 *
	 * Reset connector hardware and software state to off. This function isn't
	 * called by the core directly, only through drm_mode_config_reset().
	 * It's not a helper hook only for historical reasons.
	 *
	 * Atomic drivers can use drm_atomic_helper_connector_reset() to reset
	 * atomic state using this hook.
	 */
	void (*reset)(struct drm_connector *connector);

	/**
	 * @detect:
	 *
	 * Check to see if anything is attached to the connector. The parameter
	 * force is set to false whilst polling, true when checking the
	 * connector due to a user request. force can be used by the driver to
	 * avoid expensive, destructive operations during automated probing.
	 *
	 * This callback is optional, if not implemented the connector will be
	 * considered as always being attached.
	 *
	 * FIXME:
	 *
	 * Note that this hook is only called by the probe helper. It's not in
	 * the helper library vtable purely for historical reasons. The only DRM
	 * core	entry point to probe connector state is @fill_modes.
	 *
	 * Note that the helper library will already hold
	 * &drm_mode_config.connection_mutex. Drivers which need to grab additional
	 * locks to avoid races with concurrent modeset changes need to use
	 * &drm_connector_helper_funcs.detect_ctx instead.
	 *
	 * RETURNS:
	 *
	 * drm_connector_status indicating the connector's status.
	 */
	enum drm_connector_status (*detect)(struct drm_connector *connector,
					    bool force);

	/**
	 * @force:
	 *
	 * This function is called to update internal encoder state when the
	 * connector is forced to a certain state by userspace, either through
	 * the sysfs interfaces or on the kernel cmdline. In that case the
	 * @detect callback isn't called.
	 *
	 * FIXME:
	 *
	 * Note that this hook is only called by the probe helper. It's not in
	 * the helper library vtable purely for historical reasons. The only DRM
	 * core	entry point to probe connector state is @fill_modes.
	 */
	void (*force)(struct drm_connector *connector);

	/**
	 * @fill_modes:
	 *
	 * Entry point for output detection and basic mode validation. The
	 * driver should reprobe the output if needed (e.g. when hotplug
	 * handling is unreliable), add all detected modes to &drm_connector.modes
	 * and filter out any the device can't support in any configuration. It
	 * also needs to filter out any modes wider or higher than the
	 * parameters max_width and max_height indicate.
	 *
	 * The drivers must also prune any modes no longer valid from
	 * &drm_connector.modes. Furthermore it must update
	 * &drm_connector.status and &drm_connector.edid.  If no EDID has been
	 * received for this output connector->edid must be NULL.
	 *
	 * Drivers using the probe helpers should use
	 * drm_helper_probe_single_connector_modes() to implement this
	 * function.
	 *
	 * RETURNS:
	 *
	 * The number of modes detected and filled into &drm_connector.modes.
	 */
	int (*fill_modes)(struct drm_connector *connector, uint32_t max_width, uint32_t max_height);

	/**
	 * @set_property:
	 *
	 * This is the legacy entry point to update a property attached to the
	 * connector.
	 *
	 * This callback is optional if the driver does not support any legacy
	 * driver-private properties. For atomic drivers it is not used because
	 * property handling is done entirely in the DRM core.
	 *
	 * RETURNS:
	 *
	 * 0 on success or a negative error code on failure.
	 */
	int (*set_property)(struct drm_connector *connector, struct drm_property *property,
			     uint64_t val);

	/**
	 * @late_register:
	 *
	 * This optional hook can be used to register additional userspace
	 * interfaces attached to the connector, light backlight control, i2c,
	 * DP aux or similar interfaces. It is called late in the driver load
	 * sequence from drm_connector_register() when registering all the
	 * core drm connector interfaces. Everything added from this callback
	 * should be unregistered in the early_unregister callback.
	 *
	 * This is called while holding &drm_connector.mutex.
	 *
	 * Returns:
	 *
	 * 0 on success, or a negative error code on failure.
	 */
	int (*late_register)(struct drm_connector *connector);

	/**
	 * @early_unregister:
	 *
	 * This optional hook should be used to unregister the additional
	 * userspace interfaces attached to the connector from
	 * late_register(). It is called from drm_connector_unregister(),
	 * early in the driver unload sequence to disable userspace access
	 * before data structures are torndown.
	 *
	 * This is called while holding &drm_connector.mutex.
	 */
	void (*early_unregister)(struct drm_connector *connector);

	/**
	 * @destroy:
	 *
	 * Clean up connector resources. This is called at driver unload time
	 * through drm_mode_config_cleanup(). It can also be called at runtime
	 * when a connector is being hot-unplugged for drivers that support
	 * connector hotplugging (e.g. DisplayPort MST).
	 */
	void (*destroy)(struct drm_connector *connector);

	/**
	 * @atomic_duplicate_state:
	 *
	 * Duplicate the current atomic state for this connector and return it.
	 * The core and helpers guarantee that any atomic state duplicated with
	 * this hook and still owned by the caller (i.e. not transferred to the
	 * driver by calling &drm_mode_config_funcs.atomic_commit) will be
	 * cleaned up by calling the @atomic_destroy_state hook in this
	 * structure.
	 *
	 * This callback is mandatory for atomic drivers.
	 *
	 * Atomic drivers which don't subclass &struct drm_connector_state should use
	 * drm_atomic_helper_connector_duplicate_state(). Drivers that subclass the
	 * state structure to extend it with driver-private state should use
	 * __drm_atomic_helper_connector_duplicate_state() to make sure shared state is
	 * duplicated in a consistent fashion across drivers.
	 *
	 * It is an error to call this hook before &drm_connector.state has been
	 * initialized correctly.
	 *
	 * NOTE:
	 *
	 * If the duplicate state references refcounted resources this hook must
	 * acquire a reference for each of them. The driver must release these
	 * references again in @atomic_destroy_state.
	 *
	 * RETURNS:
	 *
	 * Duplicated atomic state or NULL when the allocation failed.
	 */
	struct drm_connector_state *(*atomic_duplicate_state)(struct drm_connector *connector);

	/**
	 * @atomic_destroy_state:
	 *
	 * Destroy a state duplicated with @atomic_duplicate_state and release
	 * or unreference all resources it references
	 *
	 * This callback is mandatory for atomic drivers.
	 */
	void (*atomic_destroy_state)(struct drm_connector *connector,
				     struct drm_connector_state *state);

	/**
	 * @atomic_set_property:
	 *
	 * Decode a driver-private property value and store the decoded value
	 * into the passed-in state structure. Since the atomic core decodes all
	 * standardized properties (even for extensions beyond the core set of
	 * properties which might not be implemented by all drivers) this
	 * requires drivers to subclass the state structure.
	 *
	 * Such driver-private properties should really only be implemented for
	 * truly hardware/vendor specific state. Instead it is preferred to
	 * standardize atomic extension and decode the properties used to expose
	 * such an extension in the core.
	 *
	 * Do not call this function directly, use
	 * drm_atomic_connector_set_property() instead.
	 *
	 * This callback is optional if the driver does not support any
	 * driver-private atomic properties.
	 *
	 * NOTE:
	 *
	 * This function is called in the state assembly phase of atomic
	 * modesets, which can be aborted for any reason (including on
	 * userspace's request to just check whether a configuration would be
	 * possible). Drivers MUST NOT touch any persistent state (hardware or
	 * software) or data structures except the passed in @state parameter.
	 *
	 * Also since userspace controls in which order properties are set this
	 * function must not do any input validation (since the state update is
	 * incomplete and hence likely inconsistent). Instead any such input
	 * validation must be done in the various atomic_check callbacks.
	 *
	 * RETURNS:
	 *
	 * 0 if the property has been found, -EINVAL if the property isn't
	 * implemented by the driver (which shouldn't ever happen, the core only
	 * asks for properties attached to this connector). No other validation
	 * is allowed by the driver. The core already checks that the property
	 * value is within the range (integer, valid enum value, ...) the driver
	 * set when registering the property.
	 */
	int (*atomic_set_property)(struct drm_connector *connector,
				   struct drm_connector_state *state,
				   struct drm_property *property,
				   uint64_t val);

	/**
	 * @atomic_get_property:
	 *
	 * Reads out the decoded driver-private property. This is used to
	 * implement the GETCONNECTOR IOCTL.
	 *
	 * Do not call this function directly, use
	 * drm_atomic_connector_get_property() instead.
	 *
	 * This callback is optional if the driver does not support any
	 * driver-private atomic properties.
	 *
	 * RETURNS:
	 *
	 * 0 on success, -EINVAL if the property isn't implemented by the
	 * driver (which shouldn't ever happen, the core only asks for
	 * properties attached to this connector).
	 */
	int (*atomic_get_property)(struct drm_connector *connector,
				   const struct drm_connector_state *state,
				   struct drm_property *property,
				   uint64_t *val);

	/**
	 * @atomic_print_state:
	 *
	 * If driver subclasses &struct drm_connector_state, it should implement
	 * this optional hook for printing additional driver specific state.
	 *
	 * Do not call this directly, use drm_atomic_connector_print_state()
	 * instead.
	 */
	void (*atomic_print_state)(struct drm_printer *p,
				   const struct drm_connector_state *state);
};

/* mode specified on the command line */
struct drm_cmdline_mode {
	bool specified;
	bool refresh_specified;
	bool bpp_specified;
	int xres, yres;
	int bpp;
	int refresh;
	bool rb;
	bool interlace;
	bool cvt;
	bool margins;
	enum drm_connector_force force;
};

/**
 * struct drm_connector - central DRM connector control structure
 *
 * Each connector may be connected to one or more CRTCs, or may be clonable by
 * another connector if they can share a CRTC.  Each connector also has a specific
 * position in the broader display (referred to as a 'screen' though it could
 * span multiple monitors).
 */
struct drm_connector {
	/** @dev: parent DRM device */
	struct drm_device *dev;
	/** @kdev: kernel device for sysfs attributes */
	struct device *kdev;
	/** @attr: sysfs attributes */
	struct device_attribute *attr;

	/**
	 * @head:
	 *
	 * List of all connectors on a @dev, linked from
	 * &drm_mode_config.connector_list. Protected by
	 * &drm_mode_config.connector_list_lock, but please only use
	 * &drm_connector_list_iter to walk this list.
	 */
	struct list_head head;

	/** @base: base KMS object */
	struct drm_mode_object base;

	/** @name: human readable name, can be overwritten by the driver */
	char *name;

	/**
	 * @mutex: Lock for general connector state, but currently only protects
	 * @registered. Most of the connector state is still protected by
	 * &drm_mode_config.mutex.
	 */
	struct mutex mutex;

	/**
	 * @index: Compacted connector index, which matches the position inside
	 * the mode_config.list for drivers not supporting hot-add/removing. Can
	 * be used as an array index. It is invariant over the lifetime of the
	 * connector.
	 */
	unsigned index;

	/**
	 * @connector_type:
	 * one of the DRM_MODE_CONNECTOR_<foo> types from drm_mode.h
	 */
	int connector_type;
	/** @connector_type_id: index into connector type enum */
	int connector_type_id;
	/**
	 * @interlace_allowed:
	 * Can this connector handle interlaced modes? Only used by
	 * drm_helper_probe_single_connector_modes() for mode filtering.
	 */
	bool interlace_allowed;
	/**
	 * @doublescan_allowed:
	 * Can this connector handle doublescan? Only used by
	 * drm_helper_probe_single_connector_modes() for mode filtering.
	 */
	bool doublescan_allowed;
	/**
	 * @stereo_allowed:
	 * Can this connector handle stereo modes? Only used by
	 * drm_helper_probe_single_connector_modes() for mode filtering.
	 */
	bool stereo_allowed;

	/**
	 * @ycbcr_420_allowed : This bool indicates if this connector is
	 * capable of handling YCBCR 420 output. While parsing the EDID
	 * blocks, its very helpful to know, if the source is capable of
	 * handling YCBCR 420 outputs.
	 */
	bool ycbcr_420_allowed;

	/**
	 * @registered: Is this connector exposed (registered) with userspace?
	 * Protected by @mutex.
	 */
	bool registered;

	/**
	 * @modes:
	 * Modes available on this connector (from fill_modes() + user).
	 * Protected by &drm_mode_config.mutex.
	 */
	struct list_head modes;

	/**
	 * @status:
	 * One of the drm_connector_status enums (connected, not, or unknown).
	 * Protected by &drm_mode_config.mutex.
	 */
	enum drm_connector_status status;

	/**
	 * @probed_modes:
	 * These are modes added by probing with DDC or the BIOS, before
	 * filtering is applied. Used by the probe helpers. Protected by
	 * &drm_mode_config.mutex.
	 */
	struct list_head probed_modes;

	/**
	 * @display_info: Display information is filled from EDID information
	 * when a display is detected. For non hot-pluggable displays such as
	 * flat panels in embedded systems, the driver should initialize the
	 * &drm_display_info.width_mm and &drm_display_info.height_mm fields
	 * with the physical size of the display.
	 *
	 * Protected by &drm_mode_config.mutex.
	 */
	struct drm_display_info display_info;

	/** @funcs: connector control functions */
	const struct drm_connector_funcs *funcs;

	/**
	 * @edid_blob_ptr: DRM property containing EDID if present. Protected by
	 * &drm_mode_config.mutex. This should be updated only by calling
	 * drm_connector_update_edid_property().
	 */
	struct drm_property_blob *edid_blob_ptr;

	/** @properties: property tracking for this connector */
	struct drm_object_properties properties;

	/**
	 * @scaling_mode_property: Optional atomic property to control the
	 * upscaling. See drm_connector_attach_content_protection_property().
	 */
	struct drm_property *scaling_mode_property;

	/**
	 * @content_protection_property: DRM ENUM property for content
	 * protection. See drm_connector_attach_content_protection_property().
	 */
	struct drm_property *content_protection_property;

	/**
	 * @path_blob_ptr:
	 *
	 * DRM blob property data for the DP MST path property. This should only
	 * be updated by calling drm_connector_set_path_property().
	 */
	struct drm_property_blob *path_blob_ptr;

#define DRM_CONNECTOR_POLL_HPD (1 << 0)
#define DRM_CONNECTOR_POLL_CONNECT (1 << 1)
#define DRM_CONNECTOR_POLL_DISCONNECT (1 << 2)

	/**
	 * @polled:
	 *
	 * Connector polling mode, a combination of
	 *
	 * DRM_CONNECTOR_POLL_HPD
	 *     The connector generates hotplug events and doesn't need to be
	 *     periodically polled. The CONNECT and DISCONNECT flags must not
	 *     be set together with the HPD flag.
	 *
	 * DRM_CONNECTOR_POLL_CONNECT
	 *     Periodically poll the connector for connection.
	 *
	 * DRM_CONNECTOR_POLL_DISCONNECT
	 *     Periodically poll the connector for disconnection, without
	 *     causing flickering even when the connector is in use. DACs should
	 *     rarely do this without a lot of testing.
	 *
	 * Set to 0 for connectors that don't support connection status
	 * discovery.
	 */
	uint8_t polled;

	/**
	 * @dpms: Current dpms state. For legacy drivers the
	 * &drm_connector_funcs.dpms callback must update this. For atomic
	 * drivers, this is handled by the core atomic code, and drivers must
	 * only take &drm_crtc_state.active into account.
	 */
	int dpms;

	/** @helper_private: mid-layer private data */
	const struct drm_connector_helper_funcs *helper_private;

	/** @cmdline_mode: mode line parsed from the kernel cmdline for this connector */
	struct drm_cmdline_mode cmdline_mode;
	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
	enum drm_connector_force force;
	/** @override_edid: has the EDID been overwritten through debugfs for testing? */
	bool override_edid;

#define DRM_CONNECTOR_MAX_ENCODER 3
	/**
	 * @encoder_ids: Valid encoders for this connector. Please only use
	 * drm_connector_for_each_possible_encoder() to enumerate these.
	 */
	uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];

	/**
	 * @encoder: Currently bound encoder driving this connector, if any.
	 * Only really meaningful for non-atomic drivers. Atomic drivers should
	 * instead look at &drm_connector_state.best_encoder, and in case they
	 * need the CRTC driving this output, &drm_connector_state.crtc.
	 */
	struct drm_encoder *encoder;

#define MAX_ELD_BYTES	128
	/** @eld: EDID-like data, if present */
	uint8_t eld[MAX_ELD_BYTES];
	/** @latency_present: AV delay info from ELD, if found */
	bool latency_present[2];
	/**
	 * @video_latency: Video latency info from ELD, if found.
	 * [0]: progressive, [1]: interlaced
	 */
	int video_latency[2];
	/**
	 * @audio_latency: audio latency info from ELD, if found
	 * [0]: progressive, [1]: interlaced
	 */
	int audio_latency[2];
	/**
	 * @null_edid_counter: track sinks that give us all zeros for the EDID.
	 * Needed to workaround some HW bugs where we get all 0s
	 */
	int null_edid_counter;

	/** @bad_edid_counter: track sinks that give us an EDID with invalid checksum */
	unsigned bad_edid_counter;

	/**
	 * @edid_corrupt: Indicates whether the last read EDID was corrupt. Used
	 * in Displayport compliance testing - Displayport Link CTS Core 1.2
	 * rev1.1 4.2.2.6
	 */
	bool edid_corrupt;

	/** @debugfs_entry: debugfs directory for this connector */
	struct dentry *debugfs_entry;

	/**
	 * @state:
	 *
	 * Current atomic state for this connector.
	 *
	 * This is protected by &drm_mode_config.connection_mutex. Note that
	 * nonblocking atomic commits access the current connector state without
	 * taking locks. Either by going through the &struct drm_atomic_state
	 * pointers, see for_each_oldnew_connector_in_state(),
	 * for_each_old_connector_in_state() and
	 * for_each_new_connector_in_state(). Or through careful ordering of
	 * atomic commit operations as implemented in the atomic helpers, see
	 * &struct drm_crtc_commit.
	 */
	struct drm_connector_state *state;

	/* DisplayID bits. FIXME: Extract into a substruct? */

	/**
	 * @tile_blob_ptr:
	 *
	 * DRM blob property data for the tile property (used mostly by DP MST).
	 * This is meant for screens which are driven through separate display
	 * pipelines represented by &drm_crtc, which might not be running with
	 * genlocked clocks. For tiled panels which are genlocked, like
	 * dual-link LVDS or dual-link DSI, the driver should try to not expose
	 * the tiling and virtualize both &drm_crtc and &drm_plane if needed.
	 *
	 * This should only be updated by calling
	 * drm_connector_set_tile_property().
	 */
	struct drm_property_blob *tile_blob_ptr;

	/** @has_tile: is this connector connected to a tiled monitor */
	bool has_tile;
	/** @tile_group: tile group for the connected monitor */
	struct drm_tile_group *tile_group;
	/** @tile_is_single_monitor: whether the tile is one monitor housing */
	bool tile_is_single_monitor;

	/** @num_h_tile: number of horizontal tiles in the tile group */
	/** @num_v_tile: number of vertical tiles in the tile group */
	uint8_t num_h_tile, num_v_tile;
	/** @tile_h_loc: horizontal location of this tile */
	/** @tile_v_loc: vertical location of this tile */
	uint8_t tile_h_loc, tile_v_loc;
	/** @tile_h_size: horizontal size of this tile. */
	/** @tile_v_size: vertical size of this tile. */
	uint16_t tile_h_size, tile_v_size;

	/**
	 * @free_node:
	 *
	 * List used only by &drm_connector_list_iter to be able to clean up a
	 * connector from any context, in conjunction with
	 * &drm_mode_config.connector_free_work.
	 */
	struct llist_node free_node;
};

#define obj_to_connector(x) container_of(x, struct drm_connector, base)

int drm_connector_init(struct drm_device *dev,
		       struct drm_connector *connector,
		       const struct drm_connector_funcs *funcs,
		       int connector_type);
int drm_connector_register(struct drm_connector *connector);
void drm_connector_unregister(struct drm_connector *connector);
int drm_connector_attach_encoder(struct drm_connector *connector,
				      struct drm_encoder *encoder);

void drm_connector_cleanup(struct drm_connector *connector);

static inline unsigned int drm_connector_index(const struct drm_connector *connector)
{
	return connector->index;
}

static inline u32 drm_connector_mask(const struct drm_connector *connector)
{
	return 1 << connector->index;
}

/**
 * drm_connector_lookup - lookup connector object
 * @dev: DRM device
 * @file_priv: drm file to check for lease against.
 * @id: connector object id
 *
 * This function looks up the connector object specified by id
 * add takes a reference to it.
 */
static inline struct drm_connector *drm_connector_lookup(struct drm_device *dev,
		struct drm_file *file_priv,
		uint32_t id)
{
	struct drm_mode_object *mo;
	mo = drm_mode_object_find(dev, file_priv, id, DRM_MODE_OBJECT_CONNECTOR);
	return mo ? obj_to_connector(mo) : NULL;
}

/**
 * drm_connector_get - acquire a connector reference
 * @connector: DRM connector
 *
 * This function increments the connector's refcount.
 */
static inline void drm_connector_get(struct drm_connector *connector)
{
	drm_mode_object_get(&connector->base);
}

/**
 * drm_connector_put - release a connector reference
 * @connector: DRM connector
 *
 * This function decrements the connector's reference count and frees the
 * object if the reference count drops to zero.
 */
static inline void drm_connector_put(struct drm_connector *connector)
{
	drm_mode_object_put(&connector->base);
}

/**
 * drm_connector_reference - acquire a connector reference
 * @connector: DRM connector
 *
 * This is a compatibility alias for drm_connector_get() and should not be
 * used by new code.
 */
static inline void drm_connector_reference(struct drm_connector *connector)
{
	drm_connector_get(connector);
}

/**
 * drm_connector_unreference - release a connector reference
 * @connector: DRM connector
 *
 * This is a compatibility alias for drm_connector_put() and should not be
 * used by new code.
 */
static inline void drm_connector_unreference(struct drm_connector *connector)
{
	drm_connector_put(connector);
}

const char *drm_get_connector_status_name(enum drm_connector_status status);
const char *drm_get_subpixel_order_name(enum subpixel_order order);
const char *drm_get_dpms_name(int val);
const char *drm_get_dvi_i_subconnector_name(int val);
const char *drm_get_dvi_i_select_name(int val);
const char *drm_get_tv_subconnector_name(int val);
const char *drm_get_tv_select_name(int val);
const char *drm_get_content_protection_name(int val);

int drm_mode_create_dvi_i_properties(struct drm_device *dev);
int drm_mode_create_tv_properties(struct drm_device *dev,
				  unsigned int num_modes,
				  const char * const modes[]);
int drm_mode_create_scaling_mode_property(struct drm_device *dev);
int drm_connector_attach_content_type_property(struct drm_connector *dev);
int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
					       u32 scaling_mode_mask);
int drm_connector_attach_content_protection_property(
		struct drm_connector *connector);
int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
int drm_mode_create_content_type_property(struct drm_device *dev);
void drm_hdmi_avi_infoframe_content_type(struct hdmi_avi_infoframe *frame,
					 const struct drm_connector_state *conn_state);

int drm_mode_create_suggested_offset_properties(struct drm_device *dev);

int drm_connector_set_path_property(struct drm_connector *connector,
				    const char *path);
int drm_connector_set_tile_property(struct drm_connector *connector);
int drm_connector_update_edid_property(struct drm_connector *connector,
				       const struct edid *edid);
void drm_connector_set_link_status_property(struct drm_connector *connector,
					    uint64_t link_status);
int drm_connector_init_panel_orientation_property(
	struct drm_connector *connector, int width, int height);

/**
 * struct drm_tile_group - Tile group metadata
 * @refcount: reference count
 * @dev: DRM device
 * @id: tile group id exposed to userspace
 * @group_data: Sink-private data identifying this group
 *
 * @group_data corresponds to displayid vend/prod/serial for external screens
 * with an EDID.
 */
struct drm_tile_group {
	struct kref refcount;
	struct drm_device *dev;
	int id;
	u8 group_data[8];
};

struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
						  char topology[8]);
struct drm_tile_group *drm_mode_get_tile_group(struct drm_device *dev,
					       char topology[8]);
void drm_mode_put_tile_group(struct drm_device *dev,
			     struct drm_tile_group *tg);

/**
 * struct drm_connector_list_iter - connector_list iterator
 *
 * This iterator tracks state needed to be able to walk the connector_list
 * within struct drm_mode_config. Only use together with
 * drm_connector_list_iter_begin(), drm_connector_list_iter_end() and
 * drm_connector_list_iter_next() respectively the convenience macro
 * drm_for_each_connector_iter().
 */
struct drm_connector_list_iter {
/* private: */
	struct drm_device *dev;
	struct drm_connector *conn;
};

void drm_connector_list_iter_begin(struct drm_device *dev,
				   struct drm_connector_list_iter *iter);
struct drm_connector *
drm_connector_list_iter_next(struct drm_connector_list_iter *iter);
void drm_connector_list_iter_end(struct drm_connector_list_iter *iter);

bool drm_connector_has_possible_encoder(struct drm_connector *connector,
					struct drm_encoder *encoder);

/**
 * drm_for_each_connector_iter - connector_list iterator macro
 * @connector: &struct drm_connector pointer used as cursor
 * @iter: &struct drm_connector_list_iter
 *
 * Note that @connector is only valid within the list body, if you want to use
 * @connector after calling drm_connector_list_iter_end() then you need to grab
 * your own reference first using drm_connector_get().
 */
#define drm_for_each_connector_iter(connector, iter) \
	while ((connector = drm_connector_list_iter_next(iter)))

/**
 * drm_connector_for_each_possible_encoder - iterate connector's possible encoders
 * @connector: &struct drm_connector pointer
 * @encoder: &struct drm_encoder pointer used as cursor
 * @__i: int iteration cursor, for macro-internal use
 */
#define drm_connector_for_each_possible_encoder(connector, encoder, __i) \
	for ((__i) = 0; (__i) < ARRAY_SIZE((connector)->encoder_ids) && \
		     (connector)->encoder_ids[(__i)] != 0; (__i)++) \
		for_each_if((encoder) = \
			    drm_encoder_find((connector)->dev, NULL, \
					     (connector)->encoder_ids[(__i)])) \

#endif