summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/drm_fb_helper.c
blob: 117237d3528bdaa2b3df0445453a80dc6a858b99 (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
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
/*
 * Copyright (c) 2006-2009 Red Hat Inc.
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
 *
 * DRM framebuffer helper 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:
 *      Dave Airlie <airlied@linux.ie>
 *      Jesse Barnes <jesse.barnes@intel.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/console.h>
#include <linux/pci.h>
#include <linux/sysrq.h>
#include <linux/vga_switcheroo.h>

#include <drm/drm_atomic.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_modeset_helper_vtables.h>
#include <drm/drm_print.h>
#include <drm/drm_vblank.h>

#include "drm_internal.h"

static bool drm_fbdev_emulation = true;
module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
MODULE_PARM_DESC(fbdev_emulation,
		 "Enable legacy fbdev emulation [default=true]");

static int drm_fbdev_overalloc = CONFIG_DRM_FBDEV_OVERALLOC;
module_param(drm_fbdev_overalloc, int, 0444);
MODULE_PARM_DESC(drm_fbdev_overalloc,
		 "Overallocation of the fbdev buffer (%) [default="
		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");

/*
 * In order to keep user-space compatibility, we want in certain use-cases
 * to keep leaking the fbdev physical address to the user-space program
 * handling the fbdev buffer.
 *
 * This is a bad habit, essentially kept to support closed-source OpenGL
 * drivers that should really be moved into open-source upstream projects
 * instead of using legacy physical addresses in user space to communicate
 * with other out-of-tree kernel modules.
 *
 * This module_param *should* be removed as soon as possible and be
 * considered as a broken and legacy behaviour from a modern fbdev device.
 */
static bool drm_leak_fbdev_smem;
#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
MODULE_PARM_DESC(drm_leak_fbdev_smem,
		 "Allow unsafe leaking fbdev physical smem address [default=false]");
#endif

static LIST_HEAD(kernel_fb_helper_list);
static DEFINE_MUTEX(kernel_fb_helper_lock);

/**
 * DOC: fbdev helpers
 *
 * The fb helper functions are useful to provide an fbdev on top of a drm kernel
 * mode setting driver. They can be used mostly independently from the crtc
 * helper functions used by many drivers to implement the kernel mode setting
 * interfaces.
 *
 * Drivers that support a dumb buffer with a virtual address and mmap support,
 * should try out the generic fbdev emulation using drm_fbdev_generic_setup().
 * It will automatically set up deferred I/O if the driver requires a shadow
 * buffer.
 *
 * Existing fbdev implementations should restore the fbdev console by using
 * drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
 * They should also notify the fb helper code from updates to the output
 * configuration by using drm_fb_helper_output_poll_changed() as their
 * &drm_mode_config_funcs.output_poll_changed callback. New implementations
 * of fbdev should be build on top of struct &drm_client_funcs, which handles
 * this automatically. Setting the old callbacks should be avoided.
 *
 * For suspend/resume consider using drm_mode_config_helper_suspend() and
 * drm_mode_config_helper_resume() which takes care of fbdev as well.
 *
 * All other functions exported by the fb helper library can be used to
 * implement the fbdev driver interface by the driver.
 *
 * It is possible, though perhaps somewhat tricky, to implement race-free
 * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
 * helper must be called first to initialize the minimum required to make
 * hotplug detection work. Drivers also need to make sure to properly set up
 * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
 * it is safe to enable interrupts and start processing hotplug events. At the
 * same time, drivers should initialize all modeset objects such as CRTCs,
 * encoders and connectors. To finish up the fbdev helper initialization, the
 * drm_fb_helper_init() function is called. To probe for all attached displays
 * and set up an initial configuration using the detected hardware, drivers
 * should call drm_fb_helper_initial_config().
 *
 * If &drm_framebuffer_funcs.dirty is set, the
 * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
 * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
 * away. This worker then calls the dirty() function ensuring that it will
 * always run in process context since the fb_*() function could be running in
 * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
 * callback it will also schedule dirty_work with the damage collected from the
 * mmap page writes.
 *
 * Deferred I/O is not compatible with SHMEM. Such drivers should request an
 * fbdev shadow buffer and call drm_fbdev_generic_setup() instead.
 */

static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
{
	uint16_t *r_base, *g_base, *b_base;

	if (crtc->funcs->gamma_set == NULL)
		return;

	r_base = crtc->gamma_store;
	g_base = r_base + crtc->gamma_size;
	b_base = g_base + crtc->gamma_size;

	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
			       crtc->gamma_size, NULL);
}

/**
 * drm_fb_helper_debug_enter - implementation for &fb_ops.fb_debug_enter
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_debug_enter(struct fb_info *info)
{
	struct drm_fb_helper *helper = info->par;
	const struct drm_crtc_helper_funcs *funcs;
	struct drm_mode_set *mode_set;

	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
		mutex_lock(&helper->client.modeset_mutex);
		drm_client_for_each_modeset(mode_set, &helper->client) {
			if (!mode_set->crtc->enabled)
				continue;

			funcs =	mode_set->crtc->helper_private;
			if (funcs->mode_set_base_atomic == NULL)
				continue;

			if (drm_drv_uses_atomic_modeset(mode_set->crtc->dev))
				continue;

			funcs->mode_set_base_atomic(mode_set->crtc,
						    mode_set->fb,
						    mode_set->x,
						    mode_set->y,
						    ENTER_ATOMIC_MODE_SET);
		}
		mutex_unlock(&helper->client.modeset_mutex);
	}

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_debug_enter);

/**
 * drm_fb_helper_debug_leave - implementation for &fb_ops.fb_debug_leave
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_debug_leave(struct fb_info *info)
{
	struct drm_fb_helper *helper = info->par;
	struct drm_client_dev *client = &helper->client;
	struct drm_device *dev = helper->dev;
	struct drm_crtc *crtc;
	const struct drm_crtc_helper_funcs *funcs;
	struct drm_mode_set *mode_set;
	struct drm_framebuffer *fb;

	mutex_lock(&client->modeset_mutex);
	drm_client_for_each_modeset(mode_set, client) {
		crtc = mode_set->crtc;
		if (drm_drv_uses_atomic_modeset(crtc->dev))
			continue;

		funcs = crtc->helper_private;
		fb = crtc->primary->fb;

		if (!crtc->enabled)
			continue;

		if (!fb) {
			drm_err(dev, "no fb to restore?\n");
			continue;
		}

		if (funcs->mode_set_base_atomic == NULL)
			continue;

		drm_fb_helper_restore_lut_atomic(mode_set->crtc);
		funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
					    crtc->y, LEAVE_ATOMIC_MODE_SET);
	}
	mutex_unlock(&client->modeset_mutex);

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_debug_leave);

static int
__drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
					    bool force)
{
	bool do_delayed;
	int ret;

	if (!drm_fbdev_emulation || !fb_helper)
		return -ENODEV;

	if (READ_ONCE(fb_helper->deferred_setup))
		return 0;

	mutex_lock(&fb_helper->lock);
	if (force) {
		/*
		 * Yes this is the _locked version which expects the master lock
		 * to be held. But for forced restores we're intentionally
		 * racing here, see drm_fb_helper_set_par().
		 */
		ret = drm_client_modeset_commit_locked(&fb_helper->client);
	} else {
		ret = drm_client_modeset_commit(&fb_helper->client);
	}

	do_delayed = fb_helper->delayed_hotplug;
	if (do_delayed)
		fb_helper->delayed_hotplug = false;
	mutex_unlock(&fb_helper->lock);

	if (do_delayed)
		drm_fb_helper_hotplug_event(fb_helper);

	return ret;
}

/**
 * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * This should be called from driver's drm &drm_driver.lastclose callback
 * when implementing an fbcon on top of kms using this helper. This ensures that
 * the user isn't greeted with a black screen when e.g. X dies.
 *
 * RETURNS:
 * Zero if everything went ok, negative error code otherwise.
 */
int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
{
	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, false);
}
EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);

#ifdef CONFIG_MAGIC_SYSRQ
/* emergency restore, don't bother with error reporting */
static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
{
	struct drm_fb_helper *helper;

	mutex_lock(&kernel_fb_helper_lock);
	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
		struct drm_device *dev = helper->dev;

		if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
			continue;

		mutex_lock(&helper->lock);
		drm_client_modeset_commit_locked(&helper->client);
		mutex_unlock(&helper->lock);
	}
	mutex_unlock(&kernel_fb_helper_lock);
}

static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);

static void drm_fb_helper_sysrq(u8 dummy1)
{
	schedule_work(&drm_fb_helper_restore_work);
}

static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
	.handler = drm_fb_helper_sysrq,
	.help_msg = "force-fb(v)",
	.action_msg = "Restore framebuffer console",
};
#else
static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
#endif

static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
{
	struct drm_fb_helper *fb_helper = info->par;

	mutex_lock(&fb_helper->lock);
	drm_client_modeset_dpms(&fb_helper->client, dpms_mode);
	mutex_unlock(&fb_helper->lock);
}

/**
 * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
 * @blank: desired blanking state
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_blank(int blank, struct fb_info *info)
{
	if (oops_in_progress)
		return -EBUSY;

	switch (blank) {
	/* Display: On; HSync: On, VSync: On */
	case FB_BLANK_UNBLANK:
		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
		break;
	/* Display: Off; HSync: On, VSync: On */
	case FB_BLANK_NORMAL:
		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
		break;
	/* Display: Off; HSync: Off, VSync: On */
	case FB_BLANK_HSYNC_SUSPEND:
		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
		break;
	/* Display: Off; HSync: On, VSync: Off */
	case FB_BLANK_VSYNC_SUSPEND:
		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
		break;
	/* Display: Off; HSync: Off, VSync: Off */
	case FB_BLANK_POWERDOWN:
		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
		break;
	}
	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_blank);

static void drm_fb_helper_resume_worker(struct work_struct *work)
{
	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
						    resume_work);

	console_lock();
	fb_set_suspend(helper->info, 0);
	console_unlock();
}

static void drm_fb_helper_fb_dirty(struct drm_fb_helper *helper)
{
	struct drm_device *dev = helper->dev;
	struct drm_clip_rect *clip = &helper->damage_clip;
	struct drm_clip_rect clip_copy;
	unsigned long flags;
	int ret;

	if (drm_WARN_ON_ONCE(dev, !helper->funcs->fb_dirty))
		return;

	spin_lock_irqsave(&helper->damage_lock, flags);
	clip_copy = *clip;
	clip->x1 = clip->y1 = ~0;
	clip->x2 = clip->y2 = 0;
	spin_unlock_irqrestore(&helper->damage_lock, flags);

	ret = helper->funcs->fb_dirty(helper, &clip_copy);
	if (ret)
		goto err;

	return;

err:
	/*
	 * Restore damage clip rectangle on errors. The next run
	 * of the damage worker will perform the update.
	 */
	spin_lock_irqsave(&helper->damage_lock, flags);
	clip->x1 = min_t(u32, clip->x1, clip_copy.x1);
	clip->y1 = min_t(u32, clip->y1, clip_copy.y1);
	clip->x2 = max_t(u32, clip->x2, clip_copy.x2);
	clip->y2 = max_t(u32, clip->y2, clip_copy.y2);
	spin_unlock_irqrestore(&helper->damage_lock, flags);
}

static void drm_fb_helper_damage_work(struct work_struct *work)
{
	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper, damage_work);

	drm_fb_helper_fb_dirty(helper);
}

/**
 * drm_fb_helper_prepare - setup a drm_fb_helper structure
 * @dev: DRM device
 * @helper: driver-allocated fbdev helper structure to set up
 * @preferred_bpp: Preferred bits per pixel for the device.
 * @funcs: pointer to structure of functions associate with this helper
 *
 * Sets up the bare minimum to make the framebuffer helper usable. This is
 * useful to implement race-free initialization of the polling helpers.
 */
void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
			   unsigned int preferred_bpp,
			   const struct drm_fb_helper_funcs *funcs)
{
	/*
	 * Pick a preferred bpp of 32 if no value has been given. This
	 * will select XRGB8888 for the framebuffer formats. All drivers
	 * have to support XRGB8888 for backwards compatibility with legacy
	 * userspace, so it's the safe choice here.
	 *
	 * TODO: Replace struct drm_mode_config.preferred_depth and this
	 *       bpp value with a preferred format that is given as struct
	 *       drm_format_info. Then derive all other values from the
	 *       format.
	 */
	if (!preferred_bpp)
		preferred_bpp = 32;

	INIT_LIST_HEAD(&helper->kernel_fb_list);
	spin_lock_init(&helper->damage_lock);
	INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
	INIT_WORK(&helper->damage_work, drm_fb_helper_damage_work);
	helper->damage_clip.x1 = helper->damage_clip.y1 = ~0;
	mutex_init(&helper->lock);
	helper->funcs = funcs;
	helper->dev = dev;
	helper->preferred_bpp = preferred_bpp;
}
EXPORT_SYMBOL(drm_fb_helper_prepare);

/**
 * drm_fb_helper_unprepare - clean up a drm_fb_helper structure
 * @fb_helper: driver-allocated fbdev helper structure to set up
 *
 * Cleans up the framebuffer helper. Inverse of drm_fb_helper_prepare().
 */
void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
{
	mutex_destroy(&fb_helper->lock);
}
EXPORT_SYMBOL(drm_fb_helper_unprepare);

/**
 * drm_fb_helper_init - initialize a &struct drm_fb_helper
 * @dev: drm device
 * @fb_helper: driver-allocated fbdev helper structure to initialize
 *
 * This allocates the structures for the fbdev helper with the given limits.
 * Note that this won't yet touch the hardware (through the driver interfaces)
 * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
 * to allow driver writes more control over the exact init sequence.
 *
 * Drivers must call drm_fb_helper_prepare() before calling this function.
 *
 * RETURNS:
 * Zero if everything went ok, nonzero otherwise.
 */
int drm_fb_helper_init(struct drm_device *dev,
		       struct drm_fb_helper *fb_helper)
{
	int ret;

	/*
	 * If this is not the generic fbdev client, initialize a drm_client
	 * without callbacks so we can use the modesets.
	 */
	if (!fb_helper->client.funcs) {
		ret = drm_client_init(dev, &fb_helper->client, "drm_fb_helper", NULL);
		if (ret)
			return ret;
	}

	dev->fb_helper = fb_helper;

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_init);

/**
 * drm_fb_helper_alloc_info - allocate fb_info and some of its members
 * @fb_helper: driver-allocated fbdev helper
 *
 * A helper to alloc fb_info and the member cmap. Called by the driver
 * within the fb_probe fb_helper callback function. Drivers do not
 * need to release the allocated fb_info structure themselves, this is
 * automatically done when calling drm_fb_helper_fini().
 *
 * RETURNS:
 * fb_info pointer if things went okay, pointer containing error code
 * otherwise
 */
struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
{
	struct device *dev = fb_helper->dev->dev;
	struct fb_info *info;
	int ret;

	info = framebuffer_alloc(0, dev);
	if (!info)
		return ERR_PTR(-ENOMEM);

	if (!drm_leak_fbdev_smem)
		info->flags |= FBINFO_HIDE_SMEM_START;

	ret = fb_alloc_cmap(&info->cmap, 256, 0);
	if (ret)
		goto err_release;

	fb_helper->info = info;
	info->skip_vt_switch = true;

	return info;

err_release:
	framebuffer_release(info);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_fb_helper_alloc_info);

/**
 * drm_fb_helper_release_info - release fb_info and its members
 * @fb_helper: driver-allocated fbdev helper
 *
 * A helper to release fb_info and the member cmap.  Drivers do not
 * need to release the allocated fb_info structure themselves, this is
 * automatically done when calling drm_fb_helper_fini().
 */
void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
{
	struct fb_info *info = fb_helper->info;

	if (!info)
		return;

	fb_helper->info = NULL;

	if (info->cmap.len)
		fb_dealloc_cmap(&info->cmap);
	framebuffer_release(info);
}
EXPORT_SYMBOL(drm_fb_helper_release_info);

/**
 * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * A wrapper around unregister_framebuffer, to release the fb_info
 * framebuffer device. This must be called before releasing all resources for
 * @fb_helper by calling drm_fb_helper_fini().
 */
void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
{
	if (fb_helper && fb_helper->info)
		unregister_framebuffer(fb_helper->info);
}
EXPORT_SYMBOL(drm_fb_helper_unregister_info);

/**
 * drm_fb_helper_fini - finialize a &struct drm_fb_helper
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * This cleans up all remaining resources associated with @fb_helper.
 */
void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
{
	if (!fb_helper)
		return;

	fb_helper->dev->fb_helper = NULL;

	if (!drm_fbdev_emulation)
		return;

	cancel_work_sync(&fb_helper->resume_work);
	cancel_work_sync(&fb_helper->damage_work);

	drm_fb_helper_release_info(fb_helper);

	mutex_lock(&kernel_fb_helper_lock);
	if (!list_empty(&fb_helper->kernel_fb_list)) {
		list_del(&fb_helper->kernel_fb_list);
		if (list_empty(&kernel_fb_helper_list))
			unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
	}
	mutex_unlock(&kernel_fb_helper_lock);

	if (!fb_helper->client.funcs)
		drm_client_release(&fb_helper->client);
}
EXPORT_SYMBOL(drm_fb_helper_fini);

static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
					  u32 width, u32 height)
{
	struct drm_clip_rect *clip = &helper->damage_clip;
	unsigned long flags;

	spin_lock_irqsave(&helper->damage_lock, flags);
	clip->x1 = min_t(u32, clip->x1, x);
	clip->y1 = min_t(u32, clip->y1, y);
	clip->x2 = max_t(u32, clip->x2, x + width);
	clip->y2 = max_t(u32, clip->y2, y + height);
	spin_unlock_irqrestore(&helper->damage_lock, flags);
}

static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
				 u32 width, u32 height)
{
	drm_fb_helper_add_damage_clip(helper, x, y, width, height);

	schedule_work(&helper->damage_work);
}

/*
 * Convert memory region into area of scanlines and pixels per
 * scanline. The parameters off and len must not reach beyond
 * the end of the framebuffer.
 */
static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len,
					       struct drm_rect *clip)
{
	u32 line_length = info->fix.line_length;
	u32 fb_height = info->var.yres;
	off_t end = off + len;
	u32 x1 = 0;
	u32 y1 = off / line_length;
	u32 x2 = info->var.xres;
	u32 y2 = DIV_ROUND_UP(end, line_length);

	/* Don't allow any of them beyond the bottom bound of display area */
	if (y1 > fb_height)
		y1 = fb_height;
	if (y2 > fb_height)
		y2 = fb_height;

	if ((y2 - y1) == 1) {
		/*
		 * We've only written to a single scanline. Try to reduce
		 * the number of horizontal pixels that need an update.
		 */
		off_t bit_off = (off % line_length) * 8;
		off_t bit_end = (end % line_length) * 8;

		x1 = bit_off / info->var.bits_per_pixel;
		x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel);
	}

	drm_rect_init(clip, x1, y1, x2 - x1, y2 - y1);
}

/* Don't use in new code. */
void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_rect damage_area;

	drm_fb_helper_memory_range_to_clip(info, off, len, &damage_area);
	drm_fb_helper_damage(fb_helper, damage_area.x1, damage_area.y1,
			     drm_rect_width(&damage_area),
			     drm_rect_height(&damage_area));
}
EXPORT_SYMBOL(drm_fb_helper_damage_range);

/* Don't use in new code. */
void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
{
	struct drm_fb_helper *fb_helper = info->par;

	drm_fb_helper_damage(fb_helper, x, y, width, height);
}
EXPORT_SYMBOL(drm_fb_helper_damage_area);

/**
 * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
 * @info: fb_info struct pointer
 * @pagereflist: list of mmap framebuffer pages that have to be flushed
 *
 * This function is used as the &fb_deferred_io.deferred_io
 * callback function for flushing the fbdev mmap writes.
 */
void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
{
	struct drm_fb_helper *helper = info->par;
	unsigned long start, end, min_off, max_off, total_size;
	struct fb_deferred_io_pageref *pageref;
	struct drm_rect damage_area;

	min_off = ULONG_MAX;
	max_off = 0;
	list_for_each_entry(pageref, pagereflist, list) {
		start = pageref->offset;
		end = start + PAGE_SIZE;
		min_off = min(min_off, start);
		max_off = max(max_off, end);
	}

	/*
	 * As we can only track pages, we might reach beyond the end
	 * of the screen and account for non-existing scanlines. Hence,
	 * keep the covered memory area within the screen buffer.
	 */
	if (info->screen_size)
		total_size = info->screen_size;
	else
		total_size = info->fix.smem_len;
	max_off = min(max_off, total_size);

	if (min_off < max_off) {
		drm_fb_helper_memory_range_to_clip(info, min_off, max_off - min_off, &damage_area);
		drm_fb_helper_damage(helper, damage_area.x1, damage_area.y1,
				     drm_rect_width(&damage_area),
				     drm_rect_height(&damage_area));
	}
}
EXPORT_SYMBOL(drm_fb_helper_deferred_io);

/**
 * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 * @suspend: whether to suspend or resume
 *
 * A wrapper around fb_set_suspend implemented by fbdev core.
 * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
 * the lock yourself
 */
void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
{
	if (fb_helper && fb_helper->info)
		fb_set_suspend(fb_helper->info, suspend);
}
EXPORT_SYMBOL(drm_fb_helper_set_suspend);

/**
 * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
 *                                      takes the console lock
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 * @suspend: whether to suspend or resume
 *
 * A wrapper around fb_set_suspend() that takes the console lock. If the lock
 * isn't available on resume, a worker is tasked with waiting for the lock
 * to become available. The console lock can be pretty contented on resume
 * due to all the printk activity.
 *
 * This function can be called multiple times with the same state since
 * &fb_info.state is checked to see if fbdev is running or not before locking.
 *
 * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
 */
void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
					bool suspend)
{
	if (!fb_helper || !fb_helper->info)
		return;

	/* make sure there's no pending/ongoing resume */
	flush_work(&fb_helper->resume_work);

	if (suspend) {
		if (fb_helper->info->state != FBINFO_STATE_RUNNING)
			return;

		console_lock();

	} else {
		if (fb_helper->info->state == FBINFO_STATE_RUNNING)
			return;

		if (!console_trylock()) {
			schedule_work(&fb_helper->resume_work);
			return;
		}
	}

	fb_set_suspend(fb_helper->info, suspend);
	console_unlock();
}
EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);

static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
{
	u32 *palette = (u32 *)info->pseudo_palette;
	int i;

	if (cmap->start + cmap->len > 16)
		return -EINVAL;

	for (i = 0; i < cmap->len; ++i) {
		u16 red = cmap->red[i];
		u16 green = cmap->green[i];
		u16 blue = cmap->blue[i];
		u32 value;

		red >>= 16 - info->var.red.length;
		green >>= 16 - info->var.green.length;
		blue >>= 16 - info->var.blue.length;
		value = (red << info->var.red.offset) |
			(green << info->var.green.offset) |
			(blue << info->var.blue.offset);
		if (info->var.transp.length > 0) {
			u32 mask = (1 << info->var.transp.length) - 1;

			mask <<= info->var.transp.offset;
			value |= mask;
		}
		palette[cmap->start + i] = value;
	}

	return 0;
}

static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_mode_set *modeset;
	struct drm_crtc *crtc;
	u16 *r, *g, *b;
	int ret = 0;

	drm_modeset_lock_all(fb_helper->dev);
	drm_client_for_each_modeset(modeset, &fb_helper->client) {
		crtc = modeset->crtc;
		if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
			ret = -EINVAL;
			goto out;
		}

		if (cmap->start + cmap->len > crtc->gamma_size) {
			ret = -EINVAL;
			goto out;
		}

		r = crtc->gamma_store;
		g = r + crtc->gamma_size;
		b = g + crtc->gamma_size;

		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));

		ret = crtc->funcs->gamma_set(crtc, r, g, b,
					     crtc->gamma_size, NULL);
		if (ret)
			goto out;
	}
out:
	drm_modeset_unlock_all(fb_helper->dev);

	return ret;
}

static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
						       struct fb_cmap *cmap)
{
	struct drm_device *dev = crtc->dev;
	struct drm_property_blob *gamma_lut;
	struct drm_color_lut *lut;
	int size = crtc->gamma_size;
	int i;

	if (!size || cmap->start + cmap->len > size)
		return ERR_PTR(-EINVAL);

	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
	if (IS_ERR(gamma_lut))
		return gamma_lut;

	lut = gamma_lut->data;
	if (cmap->start || cmap->len != size) {
		u16 *r = crtc->gamma_store;
		u16 *g = r + crtc->gamma_size;
		u16 *b = g + crtc->gamma_size;

		for (i = 0; i < cmap->start; i++) {
			lut[i].red = r[i];
			lut[i].green = g[i];
			lut[i].blue = b[i];
		}
		for (i = cmap->start + cmap->len; i < size; i++) {
			lut[i].red = r[i];
			lut[i].green = g[i];
			lut[i].blue = b[i];
		}
	}

	for (i = 0; i < cmap->len; i++) {
		lut[cmap->start + i].red = cmap->red[i];
		lut[cmap->start + i].green = cmap->green[i];
		lut[cmap->start + i].blue = cmap->blue[i];
	}

	return gamma_lut;
}

static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_device *dev = fb_helper->dev;
	struct drm_property_blob *gamma_lut = NULL;
	struct drm_modeset_acquire_ctx ctx;
	struct drm_crtc_state *crtc_state;
	struct drm_atomic_state *state;
	struct drm_mode_set *modeset;
	struct drm_crtc *crtc;
	u16 *r, *g, *b;
	bool replaced;
	int ret = 0;

	drm_modeset_acquire_init(&ctx, 0);

	state = drm_atomic_state_alloc(dev);
	if (!state) {
		ret = -ENOMEM;
		goto out_ctx;
	}

	state->acquire_ctx = &ctx;
retry:
	drm_client_for_each_modeset(modeset, &fb_helper->client) {
		crtc = modeset->crtc;

		if (!gamma_lut)
			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
		if (IS_ERR(gamma_lut)) {
			ret = PTR_ERR(gamma_lut);
			gamma_lut = NULL;
			goto out_state;
		}

		crtc_state = drm_atomic_get_crtc_state(state, crtc);
		if (IS_ERR(crtc_state)) {
			ret = PTR_ERR(crtc_state);
			goto out_state;
		}

		/*
		 * FIXME: This always uses gamma_lut. Some HW have only
		 * degamma_lut, in which case we should reset gamma_lut and set
		 * degamma_lut. See drm_crtc_legacy_gamma_set().
		 */
		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
						      NULL);
		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
						      gamma_lut);
		crtc_state->color_mgmt_changed |= replaced;
	}

	ret = drm_atomic_commit(state);
	if (ret)
		goto out_state;

	drm_client_for_each_modeset(modeset, &fb_helper->client) {
		crtc = modeset->crtc;

		r = crtc->gamma_store;
		g = r + crtc->gamma_size;
		b = g + crtc->gamma_size;

		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
	}

out_state:
	if (ret == -EDEADLK)
		goto backoff;

	drm_property_blob_put(gamma_lut);
	drm_atomic_state_put(state);
out_ctx:
	drm_modeset_drop_locks(&ctx);
	drm_modeset_acquire_fini(&ctx);

	return ret;

backoff:
	drm_atomic_state_clear(state);
	drm_modeset_backoff(&ctx);
	goto retry;
}

/**
 * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
 * @cmap: cmap to set
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_device *dev = fb_helper->dev;
	int ret;

	if (oops_in_progress)
		return -EBUSY;

	mutex_lock(&fb_helper->lock);

	if (!drm_master_internal_acquire(dev)) {
		ret = -EBUSY;
		goto unlock;
	}

	mutex_lock(&fb_helper->client.modeset_mutex);
	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
		ret = setcmap_pseudo_palette(cmap, info);
	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
		ret = setcmap_atomic(cmap, info);
	else
		ret = setcmap_legacy(cmap, info);
	mutex_unlock(&fb_helper->client.modeset_mutex);

	drm_master_internal_release(dev);
unlock:
	mutex_unlock(&fb_helper->lock);

	return ret;
}
EXPORT_SYMBOL(drm_fb_helper_setcmap);

/**
 * drm_fb_helper_ioctl - legacy ioctl implementation
 * @info: fbdev registered by the helper
 * @cmd: ioctl command
 * @arg: ioctl argument
 *
 * A helper to implement the standard fbdev ioctl. Only
 * FBIO_WAITFORVSYNC is implemented for now.
 */
int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
			unsigned long arg)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_device *dev = fb_helper->dev;
	struct drm_crtc *crtc;
	int ret = 0;

	mutex_lock(&fb_helper->lock);
	if (!drm_master_internal_acquire(dev)) {
		ret = -EBUSY;
		goto unlock;
	}

	switch (cmd) {
	case FBIO_WAITFORVSYNC:
		/*
		 * Only consider the first CRTC.
		 *
		 * This ioctl is supposed to take the CRTC number as
		 * an argument, but in fbdev times, what that number
		 * was supposed to be was quite unclear, different
		 * drivers were passing that argument differently
		 * (some by reference, some by value), and most of the
		 * userspace applications were just hardcoding 0 as an
		 * argument.
		 *
		 * The first CRTC should be the integrated panel on
		 * most drivers, so this is the best choice we can
		 * make. If we're not smart enough here, one should
		 * just consider switch the userspace to KMS.
		 */
		crtc = fb_helper->client.modesets[0].crtc;

		/*
		 * Only wait for a vblank event if the CRTC is
		 * enabled, otherwise just don't do anythintg,
		 * not even report an error.
		 */
		ret = drm_crtc_vblank_get(crtc);
		if (!ret) {
			drm_crtc_wait_one_vblank(crtc);
			drm_crtc_vblank_put(crtc);
		}

		ret = 0;
		break;
	default:
		ret = -ENOTTY;
	}

	drm_master_internal_release(dev);
unlock:
	mutex_unlock(&fb_helper->lock);
	return ret;
}
EXPORT_SYMBOL(drm_fb_helper_ioctl);

static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
				      const struct fb_var_screeninfo *var_2)
{
	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
	       var_1->grayscale == var_2->grayscale &&
	       var_1->red.offset == var_2->red.offset &&
	       var_1->red.length == var_2->red.length &&
	       var_1->red.msb_right == var_2->red.msb_right &&
	       var_1->green.offset == var_2->green.offset &&
	       var_1->green.length == var_2->green.length &&
	       var_1->green.msb_right == var_2->green.msb_right &&
	       var_1->blue.offset == var_2->blue.offset &&
	       var_1->blue.length == var_2->blue.length &&
	       var_1->blue.msb_right == var_2->blue.msb_right &&
	       var_1->transp.offset == var_2->transp.offset &&
	       var_1->transp.length == var_2->transp.length &&
	       var_1->transp.msb_right == var_2->transp.msb_right;
}

static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
					 const struct drm_format_info *format)
{
	u8 depth = format->depth;

	if (format->is_color_indexed) {
		var->red.offset = 0;
		var->green.offset = 0;
		var->blue.offset = 0;
		var->red.length = depth;
		var->green.length = depth;
		var->blue.length = depth;
		var->transp.offset = 0;
		var->transp.length = 0;
		return;
	}

	switch (depth) {
	case 15:
		var->red.offset = 10;
		var->green.offset = 5;
		var->blue.offset = 0;
		var->red.length = 5;
		var->green.length = 5;
		var->blue.length = 5;
		var->transp.offset = 15;
		var->transp.length = 1;
		break;
	case 16:
		var->red.offset = 11;
		var->green.offset = 5;
		var->blue.offset = 0;
		var->red.length = 5;
		var->green.length = 6;
		var->blue.length = 5;
		var->transp.offset = 0;
		break;
	case 24:
		var->red.offset = 16;
		var->green.offset = 8;
		var->blue.offset = 0;
		var->red.length = 8;
		var->green.length = 8;
		var->blue.length = 8;
		var->transp.offset = 0;
		var->transp.length = 0;
		break;
	case 32:
		var->red.offset = 16;
		var->green.offset = 8;
		var->blue.offset = 0;
		var->red.length = 8;
		var->green.length = 8;
		var->blue.length = 8;
		var->transp.offset = 24;
		var->transp.length = 8;
		break;
	default:
		break;
	}
}

static void __fill_var(struct fb_var_screeninfo *var, struct fb_info *info,
		       struct drm_framebuffer *fb)
{
	int i;

	var->xres_virtual = fb->width;
	var->yres_virtual = fb->height;
	var->accel_flags = 0;
	var->bits_per_pixel = drm_format_info_bpp(fb->format, 0);

	var->height = info->var.height;
	var->width = info->var.width;

	var->left_margin = var->right_margin = 0;
	var->upper_margin = var->lower_margin = 0;
	var->hsync_len = var->vsync_len = 0;
	var->sync = var->vmode = 0;
	var->rotate = 0;
	var->colorspace = 0;
	for (i = 0; i < 4; i++)
		var->reserved[i] = 0;
}

/**
 * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
 * @var: screeninfo to check
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
			    struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_framebuffer *fb = fb_helper->fb;
	const struct drm_format_info *format = fb->format;
	struct drm_device *dev = fb_helper->dev;
	unsigned int bpp;

	if (in_dbg_master())
		return -EINVAL;

	if (var->pixclock != 0) {
		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
		var->pixclock = 0;
	}

	switch (format->format) {
	case DRM_FORMAT_C1:
	case DRM_FORMAT_C2:
	case DRM_FORMAT_C4:
		/* supported format with sub-byte pixels */
		break;

	default:
		if ((drm_format_info_block_width(format, 0) > 1) ||
		    (drm_format_info_block_height(format, 0) > 1))
			return -EINVAL;
		break;
	}

	/*
	 * Changes struct fb_var_screeninfo are currently not pushed back
	 * to KMS, hence fail if different settings are requested.
	 */
	bpp = drm_format_info_bpp(format, 0);
	if (var->bits_per_pixel > bpp ||
	    var->xres > fb->width || var->yres > fb->height ||
	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
		drm_dbg_kms(dev, "fb requested width/height/bpp can't fit in current fb "
			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
			  var->xres, var->yres, var->bits_per_pixel,
			  var->xres_virtual, var->yres_virtual,
			  fb->width, fb->height, bpp);
		return -EINVAL;
	}

	__fill_var(var, info, fb);

	/*
	 * fb_pan_display() validates this, but fb_set_par() doesn't and just
	 * falls over. Note that __fill_var above adjusts y/res_virtual.
	 */
	if (var->yoffset > var->yres_virtual - var->yres ||
	    var->xoffset > var->xres_virtual - var->xres)
		return -EINVAL;

	/* We neither support grayscale nor FOURCC (also stored in here). */
	if (var->grayscale > 0)
		return -EINVAL;

	if (var->nonstd)
		return -EINVAL;

	/*
	 * Workaround for SDL 1.2, which is known to be setting all pixel format
	 * fields values to zero in some cases. We treat this situation as a
	 * kind of "use some reasonable autodetected values".
	 */
	if (!var->red.offset     && !var->green.offset    &&
	    !var->blue.offset    && !var->transp.offset   &&
	    !var->red.length     && !var->green.length    &&
	    !var->blue.length    && !var->transp.length   &&
	    !var->red.msb_right  && !var->green.msb_right &&
	    !var->blue.msb_right && !var->transp.msb_right) {
		drm_fb_helper_fill_pixel_fmt(var, format);
	}

	/*
	 * drm fbdev emulation doesn't support changing the pixel format at all,
	 * so reject all pixel format changing requests.
	 */
	if (!drm_fb_pixel_format_equal(var, &info->var)) {
		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel format\n");
		return -EINVAL;
	}

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_check_var);

/**
 * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
 * @info: fbdev registered by the helper
 *
 * This will let fbcon do the mode init and is called at initialization time by
 * the fbdev core when registering the driver, and later on through the hotplug
 * callback.
 */
int drm_fb_helper_set_par(struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct fb_var_screeninfo *var = &info->var;
	bool force;

	if (oops_in_progress)
		return -EBUSY;

	/*
	 * Normally we want to make sure that a kms master takes precedence over
	 * fbdev, to avoid fbdev flickering and occasionally stealing the
	 * display status. But Xorg first sets the vt back to text mode using
	 * the KDSET IOCTL with KD_TEXT, and only after that drops the master
	 * status when exiting.
	 *
	 * In the past this was caught by drm_fb_helper_lastclose(), but on
	 * modern systems where logind always keeps a drm fd open to orchestrate
	 * the vt switching, this doesn't work.
	 *
	 * To not break the userspace ABI we have this special case here, which
	 * is only used for the above case. Everything else uses the normal
	 * commit function, which ensures that we never steal the display from
	 * an active drm master.
	 */
	force = var->activate & FB_ACTIVATE_KD_TEXT;

	__drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_set_par);

static void pan_set(struct drm_fb_helper *fb_helper, int x, int y)
{
	struct drm_mode_set *mode_set;

	mutex_lock(&fb_helper->client.modeset_mutex);
	drm_client_for_each_modeset(mode_set, &fb_helper->client) {
		mode_set->x = x;
		mode_set->y = y;
	}
	mutex_unlock(&fb_helper->client.modeset_mutex);
}

static int pan_display_atomic(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	int ret;

	pan_set(fb_helper, var->xoffset, var->yoffset);

	ret = drm_client_modeset_commit_locked(&fb_helper->client);
	if (!ret) {
		info->var.xoffset = var->xoffset;
		info->var.yoffset = var->yoffset;
	} else
		pan_set(fb_helper, info->var.xoffset, info->var.yoffset);

	return ret;
}

static int pan_display_legacy(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_client_dev *client = &fb_helper->client;
	struct drm_mode_set *modeset;
	int ret = 0;

	mutex_lock(&client->modeset_mutex);
	drm_modeset_lock_all(fb_helper->dev);
	drm_client_for_each_modeset(modeset, client) {
		modeset->x = var->xoffset;
		modeset->y = var->yoffset;

		if (modeset->num_connectors) {
			ret = drm_mode_set_config_internal(modeset);
			if (!ret) {
				info->var.xoffset = var->xoffset;
				info->var.yoffset = var->yoffset;
			}
		}
	}
	drm_modeset_unlock_all(fb_helper->dev);
	mutex_unlock(&client->modeset_mutex);

	return ret;
}

/**
 * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
 * @var: updated screen information
 * @info: fbdev registered by the helper
 */
int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
			      struct fb_info *info)
{
	struct drm_fb_helper *fb_helper = info->par;
	struct drm_device *dev = fb_helper->dev;
	int ret;

	if (oops_in_progress)
		return -EBUSY;

	mutex_lock(&fb_helper->lock);
	if (!drm_master_internal_acquire(dev)) {
		ret = -EBUSY;
		goto unlock;
	}

	if (drm_drv_uses_atomic_modeset(dev))
		ret = pan_display_atomic(var, info);
	else
		ret = pan_display_legacy(var, info);

	drm_master_internal_release(dev);
unlock:
	mutex_unlock(&fb_helper->lock);

	return ret;
}
EXPORT_SYMBOL(drm_fb_helper_pan_display);

static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
					  size_t format_count, uint32_t bpp, uint32_t depth)
{
	struct drm_device *dev = fb_helper->dev;
	uint32_t format;
	size_t i;

	/*
	 * Do not consider YUV or other complicated formats
	 * for framebuffers. This means only legacy formats
	 * are supported (fmt->depth is a legacy field), but
	 * the framebuffer emulation can only deal with such
	 * formats, specifically RGB/BGA formats.
	 */
	format = drm_mode_legacy_fb_format(bpp, depth);
	if (!format)
		goto err;

	for (i = 0; i < format_count; ++i) {
		if (formats[i] == format)
			return format;
	}

err:
	/* We found nothing. */
	drm_warn(dev, "bpp/depth value of %u/%u not supported\n", bpp, depth);

	return DRM_FORMAT_INVALID;
}

static uint32_t drm_fb_helper_find_color_mode_format(struct drm_fb_helper *fb_helper,
						     const uint32_t *formats, size_t format_count,
						     unsigned int color_mode)
{
	struct drm_device *dev = fb_helper->dev;
	uint32_t bpp, depth;

	switch (color_mode) {
	case 1:
	case 2:
	case 4:
	case 8:
	case 16:
	case 24:
		bpp = depth = color_mode;
		break;
	case 15:
		bpp = 16;
		depth = 15;
		break;
	case 32:
		bpp = 32;
		depth = 24;
		break;
	default:
		drm_info(dev, "unsupported color mode of %d\n", color_mode);
		return DRM_FORMAT_INVALID;
	}

	return drm_fb_helper_find_format(fb_helper, formats, format_count, bpp, depth);
}

static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
				      struct drm_fb_helper_surface_size *sizes)
{
	struct drm_client_dev *client = &fb_helper->client;
	struct drm_device *dev = fb_helper->dev;
	int crtc_count = 0;
	struct drm_connector_list_iter conn_iter;
	struct drm_connector *connector;
	struct drm_mode_set *mode_set;
	uint32_t surface_format = DRM_FORMAT_INVALID;
	const struct drm_format_info *info;

	memset(sizes, 0, sizeof(*sizes));
	sizes->fb_width = (u32)-1;
	sizes->fb_height = (u32)-1;

	drm_client_for_each_modeset(mode_set, client) {
		struct drm_crtc *crtc = mode_set->crtc;
		struct drm_plane *plane = crtc->primary;

		drm_dbg_kms(dev, "test CRTC %u primary plane\n", drm_crtc_index(crtc));

		drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
		drm_client_for_each_connector_iter(connector, &conn_iter) {
			struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;

			if (!cmdline_mode->bpp_specified)
				continue;

			surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
									      plane->format_types,
									      plane->format_count,
									      cmdline_mode->bpp);
			if (surface_format != DRM_FORMAT_INVALID)
				break; /* found supported format */
		}
		drm_connector_list_iter_end(&conn_iter);

		if (surface_format != DRM_FORMAT_INVALID)
			break; /* found supported format */

		/* try preferred color mode */
		surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
								      plane->format_types,
								      plane->format_count,
								      fb_helper->preferred_bpp);
		if (surface_format != DRM_FORMAT_INVALID)
			break; /* found supported format */
	}

	if (surface_format == DRM_FORMAT_INVALID) {
		/*
		 * If none of the given color modes works, fall back
		 * to XRGB8888. Drivers are expected to provide this
		 * format for compatibility with legacy applications.
		 */
		drm_warn(dev, "No compatible format found\n");
		surface_format = drm_driver_legacy_fb_format(dev, 32, 24);
	}

	info = drm_format_info(surface_format);
	sizes->surface_bpp = drm_format_info_bpp(info, 0);
	sizes->surface_depth = info->depth;

	/* first up get a count of crtcs now in use and new min/maxes width/heights */
	crtc_count = 0;
	drm_client_for_each_modeset(mode_set, client) {
		struct drm_display_mode *desired_mode;
		int x, y, j;
		/* in case of tile group, are we the last tile vert or horiz?
		 * If no tile group you are always the last one both vertically
		 * and horizontally
		 */
		bool lastv = true, lasth = true;

		desired_mode = mode_set->mode;

		if (!desired_mode)
			continue;

		crtc_count++;

		x = mode_set->x;
		y = mode_set->y;

		sizes->surface_width  =
			max_t(u32, desired_mode->hdisplay + x, sizes->surface_width);
		sizes->surface_height =
			max_t(u32, desired_mode->vdisplay + y, sizes->surface_height);

		for (j = 0; j < mode_set->num_connectors; j++) {
			struct drm_connector *connector = mode_set->connectors[j];

			if (connector->has_tile &&
			    desired_mode->hdisplay == connector->tile_h_size &&
			    desired_mode->vdisplay == connector->tile_v_size) {
				lasth = (connector->tile_h_loc == (connector->num_h_tile - 1));
				lastv = (connector->tile_v_loc == (connector->num_v_tile - 1));
				/* cloning to multiple tiles is just crazy-talk, so: */
				break;
			}
		}

		if (lasth)
			sizes->fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes->fb_width);
		if (lastv)
			sizes->fb_height = min_t(u32, desired_mode->vdisplay + y, sizes->fb_height);
	}

	if (crtc_count == 0 || sizes->fb_width == -1 || sizes->fb_height == -1) {
		drm_info(dev, "Cannot find any crtc or sizes\n");
		return -EAGAIN;
	}

	return 0;
}

static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
				    struct drm_fb_helper_surface_size *sizes)
{
	struct drm_client_dev *client = &fb_helper->client;
	struct drm_device *dev = fb_helper->dev;
	struct drm_mode_config *config = &dev->mode_config;
	int ret;

	mutex_lock(&client->modeset_mutex);
	ret = __drm_fb_helper_find_sizes(fb_helper, sizes);
	mutex_unlock(&client->modeset_mutex);

	if (ret)
		return ret;

	/* Handle our overallocation */
	sizes->surface_height *= drm_fbdev_overalloc;
	sizes->surface_height /= 100;
	if (sizes->surface_height > config->max_height) {
		drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n",
			    config->max_height);
		sizes->surface_height = config->max_height;
	}

	return 0;
}

/*
 * Allocates the backing storage and sets up the fbdev info structure through
 * the ->fb_probe callback.
 */
static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
{
	struct drm_client_dev *client = &fb_helper->client;
	struct drm_device *dev = fb_helper->dev;
	struct drm_fb_helper_surface_size sizes;
	int ret;

	ret = drm_fb_helper_find_sizes(fb_helper, &sizes);
	if (ret) {
		/* First time: disable all crtc's.. */
		if (!fb_helper->deferred_setup)
			drm_client_modeset_commit(client);
		return ret;
	}

	/* push down into drivers */
	ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
	if (ret < 0)
		return ret;

	strcpy(fb_helper->fb->comm, "[fbcon]");

	/* Set the fb info for vgaswitcheroo clients. Does nothing otherwise. */
	if (dev_is_pci(dev->dev))
		vga_switcheroo_client_fb_set(to_pci_dev(dev->dev), fb_helper->info);

	return 0;
}

static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
				   bool is_color_indexed)
{
	info->fix.type = FB_TYPE_PACKED_PIXELS;
	info->fix.visual = is_color_indexed ? FB_VISUAL_PSEUDOCOLOR
					    : FB_VISUAL_TRUECOLOR;
	info->fix.mmio_start = 0;
	info->fix.mmio_len = 0;
	info->fix.type_aux = 0;
	info->fix.xpanstep = 1; /* doing it in hw */
	info->fix.ypanstep = 1; /* doing it in hw */
	info->fix.ywrapstep = 0;
	info->fix.accel = FB_ACCEL_NONE;

	info->fix.line_length = pitch;
}

static void drm_fb_helper_fill_var(struct fb_info *info,
				   struct drm_fb_helper *fb_helper,
				   uint32_t fb_width, uint32_t fb_height)
{
	struct drm_framebuffer *fb = fb_helper->fb;
	const struct drm_format_info *format = fb->format;

	switch (format->format) {
	case DRM_FORMAT_C1:
	case DRM_FORMAT_C2:
	case DRM_FORMAT_C4:
		/* supported format with sub-byte pixels */
		break;

	default:
		WARN_ON((drm_format_info_block_width(format, 0) > 1) ||
			(drm_format_info_block_height(format, 0) > 1));
		break;
	}

	info->pseudo_palette = fb_helper->pseudo_palette;
	info->var.xoffset = 0;
	info->var.yoffset = 0;
	__fill_var(&info->var, info, fb);
	info->var.activate = FB_ACTIVATE_NOW;

	drm_fb_helper_fill_pixel_fmt(&info->var, format);

	info->var.xres = fb_width;
	info->var.yres = fb_height;
}

/**
 * drm_fb_helper_fill_info - initializes fbdev information
 * @info: fbdev instance to set up
 * @fb_helper: fb helper instance to use as template
 * @sizes: describes fbdev size and scanout surface size
 *
 * Sets up the variable and fixed fbdev metainformation from the given fb helper
 * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
 *
 * Drivers should call this (or their equivalent setup code) from their
 * &drm_fb_helper_funcs.fb_probe callback after having allocated the fbdev
 * backing storage framebuffer.
 */
void drm_fb_helper_fill_info(struct fb_info *info,
			     struct drm_fb_helper *fb_helper,
			     struct drm_fb_helper_surface_size *sizes)
{
	struct drm_framebuffer *fb = fb_helper->fb;

	drm_fb_helper_fill_fix(info, fb->pitches[0],
			       fb->format->is_color_indexed);
	drm_fb_helper_fill_var(info, fb_helper,
			       sizes->fb_width, sizes->fb_height);

	info->par = fb_helper;
	/*
	 * The DRM drivers fbdev emulation device name can be confusing if the
	 * driver name also has a "drm" suffix on it. Leading to names such as
	 * "simpledrmdrmfb" in /proc/fb. Unfortunately, it's an uAPI and can't
	 * be changed due user-space tools (e.g: pm-utils) matching against it.
	 */
	snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb",
		 fb_helper->dev->driver->name);

}
EXPORT_SYMBOL(drm_fb_helper_fill_info);

/*
 * This is a continuation of drm_setup_crtcs() that sets up anything related
 * to the framebuffer. During initialization, drm_setup_crtcs() is called before
 * the framebuffer has been allocated (fb_helper->fb and fb_helper->info).
 * So, any setup that touches those fields needs to be done here instead of in
 * drm_setup_crtcs().
 */
static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
{
	struct drm_client_dev *client = &fb_helper->client;
	struct drm_connector_list_iter conn_iter;
	struct fb_info *info = fb_helper->info;
	unsigned int rotation, sw_rotations = 0;
	struct drm_connector *connector;
	struct drm_mode_set *modeset;

	mutex_lock(&client->modeset_mutex);
	drm_client_for_each_modeset(modeset, client) {
		if (!modeset->num_connectors)
			continue;

		modeset->fb = fb_helper->fb;

		if (drm_client_rotation(modeset, &rotation))
			/* Rotating in hardware, fbcon should not rotate */
			sw_rotations |= DRM_MODE_ROTATE_0;
		else
			sw_rotations |= rotation;
	}
	mutex_unlock(&client->modeset_mutex);

	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
	drm_client_for_each_connector_iter(connector, &conn_iter) {

		/* use first connected connector for the physical dimensions */
		if (connector->status == connector_status_connected) {
			info->var.width = connector->display_info.width_mm;
			info->var.height = connector->display_info.height_mm;
			break;
		}
	}
	drm_connector_list_iter_end(&conn_iter);

	switch (sw_rotations) {
	case DRM_MODE_ROTATE_0:
		info->fbcon_rotate_hint = FB_ROTATE_UR;
		break;
	case DRM_MODE_ROTATE_90:
		info->fbcon_rotate_hint = FB_ROTATE_CCW;
		break;
	case DRM_MODE_ROTATE_180:
		info->fbcon_rotate_hint = FB_ROTATE_UD;
		break;
	case DRM_MODE_ROTATE_270:
		info->fbcon_rotate_hint = FB_ROTATE_CW;
		break;
	default:
		/*
		 * Multiple bits are set / multiple rotations requested
		 * fbcon cannot handle separate rotation settings per
		 * output, so fallback to unrotated.
		 */
		info->fbcon_rotate_hint = FB_ROTATE_UR;
	}
}

/* Note: Drops fb_helper->lock before returning. */
static int
__drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
{
	struct drm_device *dev = fb_helper->dev;
	struct fb_info *info;
	unsigned int width, height;
	int ret;

	width = dev->mode_config.max_width;
	height = dev->mode_config.max_height;

	drm_client_modeset_probe(&fb_helper->client, width, height);
	ret = drm_fb_helper_single_fb_probe(fb_helper);
	if (ret < 0) {
		if (ret == -EAGAIN) {
			fb_helper->deferred_setup = true;
			ret = 0;
		}
		mutex_unlock(&fb_helper->lock);

		return ret;
	}
	drm_setup_crtcs_fb(fb_helper);

	fb_helper->deferred_setup = false;

	info = fb_helper->info;
	info->var.pixclock = 0;

	/* Need to drop locks to avoid recursive deadlock in
	 * register_framebuffer. This is ok because the only thing left to do is
	 * register the fbdev emulation instance in kernel_fb_helper_list. */
	mutex_unlock(&fb_helper->lock);

	ret = register_framebuffer(info);
	if (ret < 0)
		return ret;

	drm_info(dev, "fb%d: %s frame buffer device\n",
		 info->node, info->fix.id);

	mutex_lock(&kernel_fb_helper_lock);
	if (list_empty(&kernel_fb_helper_list))
		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);

	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
	mutex_unlock(&kernel_fb_helper_lock);

	return 0;
}

/**
 * drm_fb_helper_initial_config - setup a sane initial connector configuration
 * @fb_helper: fb_helper device struct
 *
 * Scans the CRTCs and connectors and tries to put together an initial setup.
 * At the moment, this is a cloned configuration across all heads with
 * a new framebuffer object as the backing store.
 *
 * Note that this also registers the fbdev and so allows userspace to call into
 * the driver through the fbdev interfaces.
 *
 * This function will call down into the &drm_fb_helper_funcs.fb_probe callback
 * to let the driver allocate and initialize the fbdev info structure and the
 * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
 * as a helper to setup simple default values for the fbdev info structure.
 *
 * HANG DEBUGGING:
 *
 * When you have fbcon support built-in or already loaded, this function will do
 * a full modeset to setup the fbdev console. Due to locking misdesign in the
 * VT/fbdev subsystem that entire modeset sequence has to be done while holding
 * console_lock. Until console_unlock is called no dmesg lines will be sent out
 * to consoles, not even serial console. This means when your driver crashes,
 * you will see absolutely nothing else but a system stuck in this function,
 * with no further output. Any kind of printk() you place within your own driver
 * or in the drm core modeset code will also never show up.
 *
 * Standard debug practice is to run the fbcon setup without taking the
 * console_lock as a hack, to be able to see backtraces and crashes on the
 * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
 * cmdline option.
 *
 * The other option is to just disable fbdev emulation since very likely the
 * first modeset from userspace will crash in the same way, and is even easier
 * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
 * kernel cmdline option.
 *
 * RETURNS:
 * Zero if everything went ok, nonzero otherwise.
 */
int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
{
	int ret;

	if (!drm_fbdev_emulation)
		return 0;

	mutex_lock(&fb_helper->lock);
	ret = __drm_fb_helper_initial_config_and_unlock(fb_helper);

	return ret;
}
EXPORT_SYMBOL(drm_fb_helper_initial_config);

/**
 * drm_fb_helper_hotplug_event - respond to a hotplug notification by
 *                               probing all the outputs attached to the fb
 * @fb_helper: driver-allocated fbdev helper, can be NULL
 *
 * Scan the connectors attached to the fb_helper and try to put together a
 * setup after notification of a change in output configuration.
 *
 * Called at runtime, takes the mode config locks to be able to check/change the
 * modeset configuration. Must be run from process context (which usually means
 * either the output polling work or a work item launched from the driver's
 * hotplug interrupt).
 *
 * Note that drivers may call this even before calling
 * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
 * for a race-free fbcon setup and will make sure that the fbdev emulation will
 * not miss any hotplug events.
 *
 * RETURNS:
 * 0 on success and a non-zero error code otherwise.
 */
int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
{
	int err = 0;

	if (!drm_fbdev_emulation || !fb_helper)
		return 0;

	mutex_lock(&fb_helper->lock);
	if (fb_helper->deferred_setup) {
		err = __drm_fb_helper_initial_config_and_unlock(fb_helper);
		return err;
	}

	if (!fb_helper->fb || !drm_master_internal_acquire(fb_helper->dev)) {
		fb_helper->delayed_hotplug = true;
		mutex_unlock(&fb_helper->lock);
		return err;
	}

	drm_master_internal_release(fb_helper->dev);

	drm_dbg_kms(fb_helper->dev, "\n");

	drm_client_modeset_probe(&fb_helper->client, fb_helper->fb->width, fb_helper->fb->height);
	drm_setup_crtcs_fb(fb_helper);
	mutex_unlock(&fb_helper->lock);

	drm_fb_helper_set_par(fb_helper->info);

	return 0;
}
EXPORT_SYMBOL(drm_fb_helper_hotplug_event);

/**
 * drm_fb_helper_lastclose - DRM driver lastclose helper for fbdev emulation
 * @dev: DRM device
 *
 * This function can be used as the &drm_driver->lastclose callback for drivers
 * that only need to call drm_fb_helper_restore_fbdev_mode_unlocked().
 */
void drm_fb_helper_lastclose(struct drm_device *dev)
{
	drm_fb_helper_restore_fbdev_mode_unlocked(dev->fb_helper);
}
EXPORT_SYMBOL(drm_fb_helper_lastclose);

/**
 * drm_fb_helper_output_poll_changed - DRM mode config \.output_poll_changed
 *                                     helper for fbdev emulation
 * @dev: DRM device
 *
 * This function can be used as the
 * &drm_mode_config_funcs.output_poll_changed callback for drivers that only
 * need to call drm_fbdev.hotplug_event().
 */
void drm_fb_helper_output_poll_changed(struct drm_device *dev)
{
	drm_fb_helper_hotplug_event(dev->fb_helper);
}
EXPORT_SYMBOL(drm_fb_helper_output_poll_changed);