aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/acpi/acpi_video.c
blob: 0972ec0e2eb8cb867868401dcf1af2446a7f9696 (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
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
/*
 *  video.c - ACPI Video Driver
 *
 *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
 *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
 *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/input.h>
#include <linux/backlight.h>
#include <linux/thermal.h>
#include <linux/sort.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/slab.h>
#include <linux/dmi.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <acpi/video.h>
#include <linux/uaccess.h>

#define PREFIX "ACPI: "

#define ACPI_VIDEO_BUS_NAME		"Video Bus"
#define ACPI_VIDEO_DEVICE_NAME		"Video Device"

#define MAX_NAME_LEN	20

#define _COMPONENT		ACPI_VIDEO_COMPONENT
ACPI_MODULE_NAME("video");

MODULE_AUTHOR("Bruno Ducrot");
MODULE_DESCRIPTION("ACPI Video Driver");
MODULE_LICENSE("GPL");

static bool brightness_switch_enabled = 1;
module_param(brightness_switch_enabled, bool, 0644);

/*
 * By default, we don't allow duplicate ACPI video bus devices
 * under the same VGA controller
 */
static bool allow_duplicates;
module_param(allow_duplicates, bool, 0644);

static int disable_backlight_sysfs_if = -1;
module_param(disable_backlight_sysfs_if, int, 0444);

#define REPORT_OUTPUT_KEY_EVENTS		0x01
#define REPORT_BRIGHTNESS_KEY_EVENTS		0x02
static int report_key_events = -1;
module_param(report_key_events, int, 0644);
MODULE_PARM_DESC(report_key_events,
	"0: none, 1: output changes, 2: brightness changes, 3: all");

/*
 * Whether the struct acpi_video_device_attrib::device_id_scheme bit should be
 * assumed even if not actually set.
 */
static bool device_id_scheme = false;
module_param(device_id_scheme, bool, 0444);

static bool only_lcd = false;
module_param(only_lcd, bool, 0444);

static int register_count;
static DEFINE_MUTEX(register_count_mutex);
static DEFINE_MUTEX(video_list_lock);
static LIST_HEAD(video_bus_head);
static int acpi_video_bus_add(struct acpi_device *device);
static int acpi_video_bus_remove(struct acpi_device *device);
static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
void acpi_video_detect_exit(void);

/*
 * Indices in the _BCL method response: the first two items are special,
 * the rest are all supported levels.
 *
 * See page 575 of the ACPI spec 3.0
 */
enum acpi_video_level_idx {
	ACPI_VIDEO_AC_LEVEL,		/* level when machine has full power */
	ACPI_VIDEO_BATTERY_LEVEL,	/* level when machine is on batteries */
	ACPI_VIDEO_FIRST_LEVEL,		/* actual supported levels begin here */
};

static const struct acpi_device_id video_device_ids[] = {
	{ACPI_VIDEO_HID, 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, video_device_ids);

static struct acpi_driver acpi_video_bus = {
	.name = "video",
	.class = ACPI_VIDEO_CLASS,
	.ids = video_device_ids,
	.ops = {
		.add = acpi_video_bus_add,
		.remove = acpi_video_bus_remove,
		.notify = acpi_video_bus_notify,
		},
};

struct acpi_video_bus_flags {
	u8 multihead:1;		/* can switch video heads */
	u8 rom:1;		/* can retrieve a video rom */
	u8 post:1;		/* can configure the head to */
	u8 reserved:5;
};

struct acpi_video_bus_cap {
	u8 _DOS:1;		/* Enable/Disable output switching */
	u8 _DOD:1;		/* Enumerate all devices attached to display adapter */
	u8 _ROM:1;		/* Get ROM Data */
	u8 _GPD:1;		/* Get POST Device */
	u8 _SPD:1;		/* Set POST Device */
	u8 _VPO:1;		/* Video POST Options */
	u8 reserved:2;
};

struct acpi_video_device_attrib {
	u32 display_index:4;	/* A zero-based instance of the Display */
	u32 display_port_attachment:4;	/* This field differentiates the display type */
	u32 display_type:4;	/* Describe the specific type in use */
	u32 vendor_specific:4;	/* Chipset Vendor Specific */
	u32 bios_can_detect:1;	/* BIOS can detect the device */
	u32 depend_on_vga:1;	/* Non-VGA output device whose power is related to
				   the VGA device. */
	u32 pipe_id:3;		/* For VGA multiple-head devices. */
	u32 reserved:10;	/* Must be 0 */

	/*
	 * The device ID might not actually follow the scheme described by this
	 * struct acpi_video_device_attrib. If it does, then this bit
	 * device_id_scheme is set; otherwise, other fields should be ignored.
	 *
	 * (but also see the global flag device_id_scheme)
	 */
	u32 device_id_scheme:1;
};

struct acpi_video_enumerated_device {
	union {
		u32 int_val;
		struct acpi_video_device_attrib attrib;
	} value;
	struct acpi_video_device *bind_info;
};

struct acpi_video_bus {
	struct acpi_device *device;
	bool backlight_registered;
	u8 dos_setting;
	struct acpi_video_enumerated_device *attached_array;
	u8 attached_count;
	u8 child_count;
	struct acpi_video_bus_cap cap;
	struct acpi_video_bus_flags flags;
	struct list_head video_device_list;
	struct mutex device_list_lock;	/* protects video_device_list */
	struct list_head entry;
	struct input_dev *input;
	char phys[32];	/* for input device */
	struct notifier_block pm_nb;
};

struct acpi_video_device_flags {
	u8 crt:1;
	u8 lcd:1;
	u8 tvout:1;
	u8 dvi:1;
	u8 bios:1;
	u8 unknown:1;
	u8 notify:1;
	u8 reserved:1;
};

struct acpi_video_device_cap {
	u8 _ADR:1;		/* Return the unique ID */
	u8 _BCL:1;		/* Query list of brightness control levels supported */
	u8 _BCM:1;		/* Set the brightness level */
	u8 _BQC:1;		/* Get current brightness level */
	u8 _BCQ:1;		/* Some buggy BIOS uses _BCQ instead of _BQC */
	u8 _DDC:1;		/* Return the EDID for this device */
};

struct acpi_video_device {
	unsigned long device_id;
	struct acpi_video_device_flags flags;
	struct acpi_video_device_cap cap;
	struct list_head entry;
	struct delayed_work switch_brightness_work;
	int switch_brightness_event;
	struct acpi_video_bus *video;
	struct acpi_device *dev;
	struct acpi_video_device_brightness *brightness;
	struct backlight_device *backlight;
	struct thermal_cooling_device *cooling_dev;
};

static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
static void acpi_video_device_rebind(struct acpi_video_bus *video);
static void acpi_video_device_bind(struct acpi_video_bus *video,
				   struct acpi_video_device *device);
static int acpi_video_device_enumerate(struct acpi_video_bus *video);
static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
			int level);
static int acpi_video_device_lcd_get_level_current(
			struct acpi_video_device *device,
			unsigned long long *level, bool raw);
static int acpi_video_get_next_level(struct acpi_video_device *device,
				     u32 level_current, u32 event);
static void acpi_video_switch_brightness(struct work_struct *work);

/* backlight device sysfs support */
static int acpi_video_get_brightness(struct backlight_device *bd)
{
	unsigned long long cur_level;
	int i;
	struct acpi_video_device *vd = bl_get_data(bd);

	if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
		return -EINVAL;
	for (i = ACPI_VIDEO_FIRST_LEVEL; i < vd->brightness->count; i++) {
		if (vd->brightness->levels[i] == cur_level)
			return i - ACPI_VIDEO_FIRST_LEVEL;
	}
	return 0;
}

static int acpi_video_set_brightness(struct backlight_device *bd)
{
	int request_level = bd->props.brightness + ACPI_VIDEO_FIRST_LEVEL;
	struct acpi_video_device *vd = bl_get_data(bd);

	cancel_delayed_work(&vd->switch_brightness_work);
	return acpi_video_device_lcd_set_level(vd,
				vd->brightness->levels[request_level]);
}

static const struct backlight_ops acpi_backlight_ops = {
	.get_brightness = acpi_video_get_brightness,
	.update_status  = acpi_video_set_brightness,
};

/* thermal cooling device callbacks */
static int video_get_max_state(struct thermal_cooling_device *cooling_dev,
			       unsigned long *state)
{
	struct acpi_device *device = cooling_dev->devdata;
	struct acpi_video_device *video = acpi_driver_data(device);

	*state = video->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
	return 0;
}

static int video_get_cur_state(struct thermal_cooling_device *cooling_dev,
			       unsigned long *state)
{
	struct acpi_device *device = cooling_dev->devdata;
	struct acpi_video_device *video = acpi_driver_data(device);
	unsigned long long level;
	int offset;

	if (acpi_video_device_lcd_get_level_current(video, &level, false))
		return -EINVAL;
	for (offset = ACPI_VIDEO_FIRST_LEVEL; offset < video->brightness->count;
	     offset++)
		if (level == video->brightness->levels[offset]) {
			*state = video->brightness->count - offset - 1;
			return 0;
		}

	return -EINVAL;
}

static int
video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
{
	struct acpi_device *device = cooling_dev->devdata;
	struct acpi_video_device *video = acpi_driver_data(device);
	int level;

	if (state >= video->brightness->count - ACPI_VIDEO_FIRST_LEVEL)
		return -EINVAL;

	state = video->brightness->count - state;
	level = video->brightness->levels[state - 1];
	return acpi_video_device_lcd_set_level(video, level);
}

static const struct thermal_cooling_device_ops video_cooling_ops = {
	.get_max_state = video_get_max_state,
	.get_cur_state = video_get_cur_state,
	.set_cur_state = video_set_cur_state,
};

/*
 * --------------------------------------------------------------------------
 *                             Video Management
 * --------------------------------------------------------------------------
 */

static int
acpi_video_device_lcd_query_levels(acpi_handle handle,
				   union acpi_object **levels)
{
	int status;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *obj;


	*levels = NULL;

	status = acpi_evaluate_object(handle, "_BCL", NULL, &buffer);
	if (!ACPI_SUCCESS(status))
		return status;
	obj = (union acpi_object *)buffer.pointer;
	if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
		printk(KERN_ERR PREFIX "Invalid _BCL data\n");
		status = -EFAULT;
		goto err;
	}

	*levels = obj;

	return 0;

err:
	kfree(buffer.pointer);

	return status;
}

static int
acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
{
	int status;
	int state;

	status = acpi_execute_simple_method(device->dev->handle,
					    "_BCM", level);
	if (ACPI_FAILURE(status)) {
		ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
		return -EIO;
	}

	device->brightness->curr = level;
	for (state = ACPI_VIDEO_FIRST_LEVEL; state < device->brightness->count;
	     state++)
		if (level == device->brightness->levels[state]) {
			if (device->backlight)
				device->backlight->props.brightness =
					state - ACPI_VIDEO_FIRST_LEVEL;
			return 0;
		}

	ACPI_ERROR((AE_INFO, "Current brightness invalid"));
	return -EINVAL;
}

/*
 * For some buggy _BQC methods, we need to add a constant value to
 * the _BQC return value to get the actual current brightness level
 */

static int bqc_offset_aml_bug_workaround;
static int video_set_bqc_offset(const struct dmi_system_id *d)
{
	bqc_offset_aml_bug_workaround = 9;
	return 0;
}

static int video_disable_backlight_sysfs_if(
	const struct dmi_system_id *d)
{
	if (disable_backlight_sysfs_if == -1)
		disable_backlight_sysfs_if = 1;
	return 0;
}

static int video_set_device_id_scheme(const struct dmi_system_id *d)
{
	device_id_scheme = true;
	return 0;
}

static int video_enable_only_lcd(const struct dmi_system_id *d)
{
	only_lcd = true;
	return 0;
}

static int video_set_report_key_events(const struct dmi_system_id *id)
{
	if (report_key_events == -1)
		report_key_events = (uintptr_t)id->driver_data;
	return 0;
}

static const struct dmi_system_id video_dmi_table[] = {
	/*
	 * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
	 */
	{
	 .callback = video_set_bqc_offset,
	 .ident = "Acer Aspire 5720",
	 .matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
		},
	},
	{
	 .callback = video_set_bqc_offset,
	 .ident = "Acer Aspire 5710Z",
	 .matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
		},
	},
	{
	 .callback = video_set_bqc_offset,
	 .ident = "eMachines E510",
	 .matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
		DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
		},
	},
	{
	 .callback = video_set_bqc_offset,
	 .ident = "Acer Aspire 5315",
	 .matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
		},
	},
	{
	 .callback = video_set_bqc_offset,
	 .ident = "Acer Aspire 7720",
	 .matches = {
		DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
		DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
		},
	},

	/*
	 * Some machines have a broken acpi-video interface for brightness
	 * control, but still need an acpi_video_device_lcd_set_level() call
	 * on resume to turn the backlight power on.  We Enable backlight
	 * control on these systems, but do not register a backlight sysfs
	 * as brightness control does not work.
	 */
	{
	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
	 .callback = video_disable_backlight_sysfs_if,
	 .ident = "Toshiba Portege R700",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R700"),
		},
	},
	{
	 /* https://bugs.freedesktop.org/show_bug.cgi?id=82634 */
	 .callback = video_disable_backlight_sysfs_if,
	 .ident = "Toshiba Portege R830",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
		DMI_MATCH(DMI_PRODUCT_NAME, "PORTEGE R830"),
		},
	},
	{
	 /* https://bugzilla.kernel.org/show_bug.cgi?id=21012 */
	 .callback = video_disable_backlight_sysfs_if,
	 .ident = "Toshiba Satellite R830",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
		DMI_MATCH(DMI_PRODUCT_NAME, "SATELLITE R830"),
		},
	},
	/*
	 * Some machine's _DOD IDs don't have bit 31(Device ID Scheme) set
	 * but the IDs actually follow the Device ID Scheme.
	 */
	{
	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
	 .callback = video_set_device_id_scheme,
	 .ident = "ESPRIMO Mobile M9410",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
		},
	},
	/*
	 * Some machines have multiple video output devices, but only the one
	 * that is the type of LCD can do the backlight control so we should not
	 * register backlight interface for other video output devices.
	 */
	{
	 /* https://bugzilla.kernel.org/show_bug.cgi?id=104121 */
	 .callback = video_enable_only_lcd,
	 .ident = "ESPRIMO Mobile M9410",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU SIEMENS"),
		DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO Mobile M9410"),
		},
	},
	/*
	 * Some machines report wrong key events on the acpi-bus, suppress
	 * key event reporting on these.  Note this is only intended to work
	 * around events which are plain wrong. In some cases we get double
	 * events, in this case acpi-video is considered the canonical source
	 * and the events from the other source should be filtered. E.g.
	 * by calling acpi_video_handles_brightness_key_presses() from the
	 * vendor acpi/wmi driver or by using /lib/udev/hwdb.d/60-keyboard.hwdb
	 */
	{
	 .callback = video_set_report_key_events,
	 .driver_data = (void *)((uintptr_t)REPORT_OUTPUT_KEY_EVENTS),
	 .ident = "Dell Vostro V131",
	 .matches = {
		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
		DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
		},
	},
	{}
};

static unsigned long long
acpi_video_bqc_value_to_level(struct acpi_video_device *device,
			      unsigned long long bqc_value)
{
	unsigned long long level;

	if (device->brightness->flags._BQC_use_index) {
		/*
		 * _BQC returns an index that doesn't account for the first 2
		 * items with special meaning (see enum acpi_video_level_idx),
		 * so we need to compensate for that by offsetting ourselves
		 */
		if (device->brightness->flags._BCL_reversed)
			bqc_value = device->brightness->count -
				ACPI_VIDEO_FIRST_LEVEL - 1 - bqc_value;

		level = device->brightness->levels[bqc_value +
		                                   ACPI_VIDEO_FIRST_LEVEL];
	} else {
		level = bqc_value;
	}

	level += bqc_offset_aml_bug_workaround;

	return level;
}

static int
acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
					unsigned long long *level, bool raw)
{
	acpi_status status = AE_OK;
	int i;

	if (device->cap._BQC || device->cap._BCQ) {
		char *buf = device->cap._BQC ? "_BQC" : "_BCQ";

		status = acpi_evaluate_integer(device->dev->handle, buf,
						NULL, level);
		if (ACPI_SUCCESS(status)) {
			if (raw) {
				/*
				 * Caller has indicated he wants the raw
				 * value returned by _BQC, so don't furtherly
				 * mess with the value.
				 */
				return 0;
			}

			*level = acpi_video_bqc_value_to_level(device, *level);

			for (i = ACPI_VIDEO_FIRST_LEVEL;
			     i < device->brightness->count; i++)
				if (device->brightness->levels[i] == *level) {
					device->brightness->curr = *level;
					return 0;
				}
			/*
			 * BQC returned an invalid level.
			 * Stop using it.
			 */
			ACPI_WARNING((AE_INFO,
				      "%s returned an invalid level",
				      buf));
			device->cap._BQC = device->cap._BCQ = 0;
		} else {
			/*
			 * Fixme:
			 * should we return an error or ignore this failure?
			 * dev->brightness->curr is a cached value which stores
			 * the correct current backlight level in most cases.
			 * ACPI video backlight still works w/ buggy _BQC.
			 * http://bugzilla.kernel.org/show_bug.cgi?id=12233
			 */
			ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
			device->cap._BQC = device->cap._BCQ = 0;
		}
	}

	*level = device->brightness->curr;
	return 0;
}

static int
acpi_video_device_EDID(struct acpi_video_device *device,
		       union acpi_object **edid, ssize_t length)
{
	int status;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *obj;
	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
	struct acpi_object_list args = { 1, &arg0 };


	*edid = NULL;

	if (!device)
		return -ENODEV;
	if (length == 128)
		arg0.integer.value = 1;
	else if (length == 256)
		arg0.integer.value = 2;
	else
		return -EINVAL;

	status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
	if (ACPI_FAILURE(status))
		return -ENODEV;

	obj = buffer.pointer;

	if (obj && obj->type == ACPI_TYPE_BUFFER)
		*edid = obj;
	else {
		printk(KERN_ERR PREFIX "Invalid _DDC data\n");
		status = -EFAULT;
		kfree(obj);
	}

	return status;
}

/* bus */

/*
 *  Arg:
 *	video		: video bus device pointer
 *	bios_flag	:
 *		0.	The system BIOS should NOT automatically switch(toggle)
 *			the active display output.
 *		1.	The system BIOS should automatically switch (toggle) the
 *			active display output. No switch event.
 *		2.	The _DGS value should be locked.
 *		3.	The system BIOS should not automatically switch (toggle) the
 *			active display output, but instead generate the display switch
 *			event notify code.
 *	lcd_flag	:
 *		0.	The system BIOS should automatically control the brightness level
 *			of the LCD when the power changes from AC to DC
 *		1.	The system BIOS should NOT automatically control the brightness
 *			level of the LCD when the power changes from AC to DC.
 *  Return Value:
 *		-EINVAL	wrong arg.
 */

static int
acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
{
	acpi_status status;

	if (!video->cap._DOS)
		return 0;

	if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
		return -EINVAL;
	video->dos_setting = (lcd_flag << 2) | bios_flag;
	status = acpi_execute_simple_method(video->device->handle, "_DOS",
					    (lcd_flag << 2) | bios_flag);
	if (ACPI_FAILURE(status))
		return -EIO;

	return 0;
}

/*
 * Simple comparison function used to sort backlight levels.
 */

static int
acpi_video_cmp_level(const void *a, const void *b)
{
	return *(int *)a - *(int *)b;
}

/*
 * Decides if _BQC/_BCQ for this system is usable
 *
 * We do this by changing the level first and then read out the current
 * brightness level, if the value does not match, find out if it is using
 * index. If not, clear the _BQC/_BCQ capability.
 */
static int acpi_video_bqc_quirk(struct acpi_video_device *device,
				int max_level, int current_level)
{
	struct acpi_video_device_brightness *br = device->brightness;
	int result;
	unsigned long long level;
	int test_level;

	/* don't mess with existing known broken systems */
	if (bqc_offset_aml_bug_workaround)
		return 0;

	/*
	 * Some systems always report current brightness level as maximum
	 * through _BQC, we need to test another value for them. However,
	 * there is a subtlety:
	 *
	 * If the _BCL package ordering is descending, the first level
	 * (br->levels[2]) is likely to be 0, and if the number of levels
	 * matches the number of steps, we might confuse a returned level to
	 * mean the index.
	 *
	 * For example:
	 *
	 *     current_level = max_level = 100
	 *     test_level = 0
	 *     returned level = 100
	 *
	 * In this case 100 means the level, not the index, and _BCM failed.
	 * Still, if the _BCL package ordering is descending, the index of
	 * level 0 is also 100, so we assume _BQC is indexed, when it's not.
	 *
	 * This causes all _BQC calls to return bogus values causing weird
	 * behavior from the user's perspective.  For example:
	 *
	 * xbacklight -set 10; xbacklight -set 20;
	 *
	 * would flash to 90% and then slowly down to the desired level (20).
	 *
	 * The solution is simple; test anything other than the first level
	 * (e.g. 1).
	 */
	test_level = current_level == max_level
		? br->levels[ACPI_VIDEO_FIRST_LEVEL + 1]
		: max_level;

	result = acpi_video_device_lcd_set_level(device, test_level);
	if (result)
		return result;

	result = acpi_video_device_lcd_get_level_current(device, &level, true);
	if (result)
		return result;

	if (level != test_level) {
		/* buggy _BQC found, need to find out if it uses index */
		if (level < br->count) {
			if (br->flags._BCL_reversed)
				level = br->count - ACPI_VIDEO_FIRST_LEVEL - 1 - level;
			if (br->levels[level + ACPI_VIDEO_FIRST_LEVEL] == test_level)
				br->flags._BQC_use_index = 1;
		}

		if (!br->flags._BQC_use_index)
			device->cap._BQC = device->cap._BCQ = 0;
	}

	return 0;
}

int acpi_video_get_levels(struct acpi_device *device,
			  struct acpi_video_device_brightness **dev_br,
			  int *pmax_level)
{
	union acpi_object *obj = NULL;
	int i, max_level = 0, count = 0, level_ac_battery = 0;
	union acpi_object *o;
	struct acpi_video_device_brightness *br = NULL;
	int result = 0;
	u32 value;

	if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device->handle,
								&obj))) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
						"LCD brightness level\n"));
		result = -ENODEV;
		goto out;
	}

	if (obj->package.count < ACPI_VIDEO_FIRST_LEVEL) {
		result = -EINVAL;
		goto out;
	}

	br = kzalloc(sizeof(*br), GFP_KERNEL);
	if (!br) {
		printk(KERN_ERR "can't allocate memory\n");
		result = -ENOMEM;
		goto out;
	}

	/*
	 * Note that we have to reserve 2 extra items (ACPI_VIDEO_FIRST_LEVEL),
	 * in order to account for buggy BIOS which don't export the first two
	 * special levels (see below)
	 */
	br->levels = kmalloc((obj->package.count + ACPI_VIDEO_FIRST_LEVEL) *
	                     sizeof(*br->levels), GFP_KERNEL);
	if (!br->levels) {
		result = -ENOMEM;
		goto out_free;
	}

	for (i = 0; i < obj->package.count; i++) {
		o = (union acpi_object *)&obj->package.elements[i];
		if (o->type != ACPI_TYPE_INTEGER) {
			printk(KERN_ERR PREFIX "Invalid data\n");
			continue;
		}
		value = (u32) o->integer.value;
		/* Skip duplicate entries */
		if (count > ACPI_VIDEO_FIRST_LEVEL
		    && br->levels[count - 1] == value)
			continue;

		br->levels[count] = value;

		if (br->levels[count] > max_level)
			max_level = br->levels[count];
		count++;
	}

	/*
	 * some buggy BIOS don't export the levels
	 * when machine is on AC/Battery in _BCL package.
	 * In this case, the first two elements in _BCL packages
	 * are also supported brightness levels that OS should take care of.
	 */
	for (i = ACPI_VIDEO_FIRST_LEVEL; i < count; i++) {
		if (br->levels[i] == br->levels[ACPI_VIDEO_AC_LEVEL])
			level_ac_battery++;
		if (br->levels[i] == br->levels[ACPI_VIDEO_BATTERY_LEVEL])
			level_ac_battery++;
	}

	if (level_ac_battery < ACPI_VIDEO_FIRST_LEVEL) {
		level_ac_battery = ACPI_VIDEO_FIRST_LEVEL - level_ac_battery;
		br->flags._BCL_no_ac_battery_levels = 1;
		for (i = (count - 1 + level_ac_battery);
		     i >= ACPI_VIDEO_FIRST_LEVEL; i--)
			br->levels[i] = br->levels[i - level_ac_battery];
		count += level_ac_battery;
	} else if (level_ac_battery > ACPI_VIDEO_FIRST_LEVEL)
		ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));

	/* Check if the _BCL package is in a reversed order */
	if (max_level == br->levels[ACPI_VIDEO_FIRST_LEVEL]) {
		br->flags._BCL_reversed = 1;
		sort(&br->levels[ACPI_VIDEO_FIRST_LEVEL],
		     count - ACPI_VIDEO_FIRST_LEVEL,
		     sizeof(br->levels[ACPI_VIDEO_FIRST_LEVEL]),
		     acpi_video_cmp_level, NULL);
	} else if (max_level != br->levels[count - 1])
		ACPI_ERROR((AE_INFO,
			    "Found unordered _BCL package"));

	br->count = count;
	*dev_br = br;
	if (pmax_level)
		*pmax_level = max_level;

out:
	kfree(obj);
	return result;
out_free:
	kfree(br);
	goto out;
}
EXPORT_SYMBOL(acpi_video_get_levels);

/*
 *  Arg:
 *	device	: video output device (LCD, CRT, ..)
 *
 *  Return Value:
 *	Maximum brightness level
 *
 *  Allocate and initialize device->brightness.
 */

static int
acpi_video_init_brightness(struct acpi_video_device *device)
{
	int i, max_level = 0;
	unsigned long long level, level_old;
	struct acpi_video_device_brightness *br = NULL;
	int result = -EINVAL;

	result = acpi_video_get_levels(device->dev, &br, &max_level);
	if (result)
		return result;
	device->brightness = br;

	/* _BQC uses INDEX while _BCL uses VALUE in some laptops */
	br->curr = level = max_level;

	if (!device->cap._BQC)
		goto set_level;

	result = acpi_video_device_lcd_get_level_current(device,
							 &level_old, true);
	if (result)
		goto out_free_levels;

	result = acpi_video_bqc_quirk(device, max_level, level_old);
	if (result)
		goto out_free_levels;
	/*
	 * cap._BQC may get cleared due to _BQC is found to be broken
	 * in acpi_video_bqc_quirk, so check again here.
	 */
	if (!device->cap._BQC)
		goto set_level;

	level = acpi_video_bqc_value_to_level(device, level_old);
	/*
	 * On some buggy laptops, _BQC returns an uninitialized
	 * value when invoked for the first time, i.e.
	 * level_old is invalid (no matter whether it's a level
	 * or an index). Set the backlight to max_level in this case.
	 */
	for (i = ACPI_VIDEO_FIRST_LEVEL; i < br->count; i++)
		if (level == br->levels[i])
			break;
	if (i == br->count || !level)
		level = max_level;

set_level:
	result = acpi_video_device_lcd_set_level(device, level);
	if (result)
		goto out_free_levels;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	                  "found %d brightness levels\n",
	                  br->count - ACPI_VIDEO_FIRST_LEVEL));
	return 0;

out_free_levels:
	kfree(br->levels);
	kfree(br);
	device->brightness = NULL;
	return result;
}

/*
 *  Arg:
 *	device	: video output device (LCD, CRT, ..)
 *
 *  Return Value:
 *	None
 *
 *  Find out all required AML methods defined under the output
 *  device.
 */

static void acpi_video_device_find_cap(struct acpi_video_device *device)
{
	if (acpi_has_method(device->dev->handle, "_ADR"))
		device->cap._ADR = 1;
	if (acpi_has_method(device->dev->handle, "_BCL"))
		device->cap._BCL = 1;
	if (acpi_has_method(device->dev->handle, "_BCM"))
		device->cap._BCM = 1;
	if (acpi_has_method(device->dev->handle, "_BQC")) {
		device->cap._BQC = 1;
	} else if (acpi_has_method(device->dev->handle, "_BCQ")) {
		printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
		device->cap._BCQ = 1;
	}

	if (acpi_has_method(device->dev->handle, "_DDC"))
		device->cap._DDC = 1;
}

/*
 *  Arg:
 *	device	: video output device (VGA)
 *
 *  Return Value:
 *	None
 *
 *  Find out all required AML methods defined under the video bus device.
 */

static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
{
	if (acpi_has_method(video->device->handle, "_DOS"))
		video->cap._DOS = 1;
	if (acpi_has_method(video->device->handle, "_DOD"))
		video->cap._DOD = 1;
	if (acpi_has_method(video->device->handle, "_ROM"))
		video->cap._ROM = 1;
	if (acpi_has_method(video->device->handle, "_GPD"))
		video->cap._GPD = 1;
	if (acpi_has_method(video->device->handle, "_SPD"))
		video->cap._SPD = 1;
	if (acpi_has_method(video->device->handle, "_VPO"))
		video->cap._VPO = 1;
}

/*
 * Check whether the video bus device has required AML method to
 * support the desired features
 */

static int acpi_video_bus_check(struct acpi_video_bus *video)
{
	acpi_status status = -ENOENT;
	struct pci_dev *dev;

	if (!video)
		return -EINVAL;

	dev = acpi_get_pci_dev(video->device->handle);
	if (!dev)
		return -ENODEV;
	pci_dev_put(dev);

	/*
	 * Since there is no HID, CID and so on for VGA driver, we have
	 * to check well known required nodes.
	 */

	/* Does this device support video switching? */
	if (video->cap._DOS || video->cap._DOD) {
		if (!video->cap._DOS) {
			printk(KERN_WARNING FW_BUG
				"ACPI(%s) defines _DOD but not _DOS\n",
				acpi_device_bid(video->device));
		}
		video->flags.multihead = 1;
		status = 0;
	}

	/* Does this device support retrieving a video ROM? */
	if (video->cap._ROM) {
		video->flags.rom = 1;
		status = 0;
	}

	/* Does this device support configuring which video device to POST? */
	if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
		video->flags.post = 1;
		status = 0;
	}

	return status;
}

/*
 * --------------------------------------------------------------------------
 *                               Driver Interface
 * --------------------------------------------------------------------------
 */

/* device interface */
static struct acpi_video_device_attrib *
acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
{
	struct acpi_video_enumerated_device *ids;
	int i;

	for (i = 0; i < video->attached_count; i++) {
		ids = &video->attached_array[i];
		if ((ids->value.int_val & 0xffff) == device_id)
			return &ids->value.attrib;
	}

	return NULL;
}

static int
acpi_video_get_device_type(struct acpi_video_bus *video,
			   unsigned long device_id)
{
	struct acpi_video_enumerated_device *ids;
	int i;

	for (i = 0; i < video->attached_count; i++) {
		ids = &video->attached_array[i];
		if ((ids->value.int_val & 0xffff) == device_id)
			return ids->value.int_val;
	}

	return 0;
}

static int
acpi_video_bus_get_one_device(struct acpi_device *device,
			      struct acpi_video_bus *video)
{
	unsigned long long device_id;
	int status, device_type;
	struct acpi_video_device *data;
	struct acpi_video_device_attrib *attribute;

	status =
	    acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
	/* Some device omits _ADR, we skip them instead of fail */
	if (ACPI_FAILURE(status))
		return 0;

	data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
	device->driver_data = data;

	data->device_id = device_id;
	data->video = video;
	data->dev = device;
	INIT_DELAYED_WORK(&data->switch_brightness_work,
			  acpi_video_switch_brightness);

	attribute = acpi_video_get_device_attr(video, device_id);

	if (attribute && (attribute->device_id_scheme || device_id_scheme)) {
		switch (attribute->display_type) {
		case ACPI_VIDEO_DISPLAY_CRT:
			data->flags.crt = 1;
			break;
		case ACPI_VIDEO_DISPLAY_TV:
			data->flags.tvout = 1;
			break;
		case ACPI_VIDEO_DISPLAY_DVI:
			data->flags.dvi = 1;
			break;
		case ACPI_VIDEO_DISPLAY_LCD:
			data->flags.lcd = 1;
			break;
		default:
			data->flags.unknown = 1;
			break;
		}
		if (attribute->bios_can_detect)
			data->flags.bios = 1;
	} else {
		/* Check for legacy IDs */
		device_type = acpi_video_get_device_type(video, device_id);
		/* Ignore bits 16 and 18-20 */
		switch (device_type & 0xffe2ffff) {
		case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
			data->flags.crt = 1;
			break;
		case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
			data->flags.lcd = 1;
			break;
		case ACPI_VIDEO_DISPLAY_LEGACY_TV:
			data->flags.tvout = 1;
			break;
		default:
			data->flags.unknown = 1;
		}
	}

	acpi_video_device_bind(video, data);
	acpi_video_device_find_cap(data);

	mutex_lock(&video->device_list_lock);
	list_add_tail(&data->entry, &video->video_device_list);
	mutex_unlock(&video->device_list_lock);

	return status;
}

/*
 *  Arg:
 *	video	: video bus device
 *
 *  Return:
 *	none
 *
 *  Enumerate the video device list of the video bus,
 *  bind the ids with the corresponding video devices
 *  under the video bus.
 */

static void acpi_video_device_rebind(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev;

	mutex_lock(&video->device_list_lock);

	list_for_each_entry(dev, &video->video_device_list, entry)
		acpi_video_device_bind(video, dev);

	mutex_unlock(&video->device_list_lock);
}

/*
 *  Arg:
 *	video	: video bus device
 *	device	: video output device under the video
 *		bus
 *
 *  Return:
 *	none
 *
 *  Bind the ids with the corresponding video devices
 *  under the video bus.
 */

static void
acpi_video_device_bind(struct acpi_video_bus *video,
		       struct acpi_video_device *device)
{
	struct acpi_video_enumerated_device *ids;
	int i;

	for (i = 0; i < video->attached_count; i++) {
		ids = &video->attached_array[i];
		if (device->device_id == (ids->value.int_val & 0xffff)) {
			ids->bind_info = device;
			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
		}
	}
}

static bool acpi_video_device_in_dod(struct acpi_video_device *device)
{
	struct acpi_video_bus *video = device->video;
	int i;

	/*
	 * If we have a broken _DOD or we have more than 8 output devices
	 * under the graphics controller node that we can't proper deal with
	 * in the operation region code currently, no need to test.
	 */
	if (!video->attached_count || video->child_count > 8)
		return true;

	for (i = 0; i < video->attached_count; i++) {
		if ((video->attached_array[i].value.int_val & 0xfff) ==
		    (device->device_id & 0xfff))
			return true;
	}

	return false;
}

/*
 *  Arg:
 *	video	: video bus device
 *
 *  Return:
 *	< 0	: error
 *
 *  Call _DOD to enumerate all devices attached to display adapter
 *
 */

static int acpi_video_device_enumerate(struct acpi_video_bus *video)
{
	int status;
	int count;
	int i;
	struct acpi_video_enumerated_device *active_list;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *dod = NULL;
	union acpi_object *obj;

	if (!video->cap._DOD)
		return AE_NOT_EXIST;

	status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
	if (!ACPI_SUCCESS(status)) {
		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
		return status;
	}

	dod = buffer.pointer;
	if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
		ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
		status = -EFAULT;
		goto out;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
			  dod->package.count));

	active_list = kcalloc(1 + dod->package.count,
			      sizeof(struct acpi_video_enumerated_device),
			      GFP_KERNEL);
	if (!active_list) {
		status = -ENOMEM;
		goto out;
	}

	count = 0;
	for (i = 0; i < dod->package.count; i++) {
		obj = &dod->package.elements[i];

		if (obj->type != ACPI_TYPE_INTEGER) {
			printk(KERN_ERR PREFIX
				"Invalid _DOD data in element %d\n", i);
			continue;
		}

		active_list[count].value.int_val = obj->integer.value;
		active_list[count].bind_info = NULL;
		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
				  (int)obj->integer.value));
		count++;
	}

	kfree(video->attached_array);

	video->attached_array = active_list;
	video->attached_count = count;

out:
	kfree(buffer.pointer);
	return status;
}

static int
acpi_video_get_next_level(struct acpi_video_device *device,
			  u32 level_current, u32 event)
{
	int min, max, min_above, max_below, i, l, delta = 255;
	max = max_below = 0;
	min = min_above = 255;
	/* Find closest level to level_current */
	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
		l = device->brightness->levels[i];
		if (abs(l - level_current) < abs(delta)) {
			delta = l - level_current;
			if (!delta)
				break;
		}
	}
	/* Ajust level_current to closest available level */
	level_current += delta;
	for (i = ACPI_VIDEO_FIRST_LEVEL; i < device->brightness->count; i++) {
		l = device->brightness->levels[i];
		if (l < min)
			min = l;
		if (l > max)
			max = l;
		if (l < min_above && l > level_current)
			min_above = l;
		if (l > max_below && l < level_current)
			max_below = l;
	}

	switch (event) {
	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
		return (level_current < max) ? min_above : min;
	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
		return (level_current < max) ? min_above : max;
	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
		return (level_current > min) ? max_below : min;
	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
		return 0;
	default:
		return level_current;
	}
}

static void
acpi_video_switch_brightness(struct work_struct *work)
{
	struct acpi_video_device *device = container_of(to_delayed_work(work),
			     struct acpi_video_device, switch_brightness_work);
	unsigned long long level_current, level_next;
	int event = device->switch_brightness_event;
	int result = -EINVAL;

	/* no warning message if acpi_backlight=vendor or a quirk is used */
	if (!device->backlight)
		return;

	if (!device->brightness)
		goto out;

	result = acpi_video_device_lcd_get_level_current(device,
							 &level_current,
							 false);
	if (result)
		goto out;

	level_next = acpi_video_get_next_level(device, level_current, event);

	result = acpi_video_device_lcd_set_level(device, level_next);

	if (!result)
		backlight_force_update(device->backlight,
				       BACKLIGHT_UPDATE_HOTKEY);

out:
	if (result)
		printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
}

int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
			void **edid)
{
	struct acpi_video_bus *video;
	struct acpi_video_device *video_device;
	union acpi_object *buffer = NULL;
	acpi_status status;
	int i, length;

	if (!device || !acpi_driver_data(device))
		return -EINVAL;

	video = acpi_driver_data(device);

	for (i = 0; i < video->attached_count; i++) {
		video_device = video->attached_array[i].bind_info;
		length = 256;

		if (!video_device)
			continue;

		if (!video_device->cap._DDC)
			continue;

		if (type) {
			switch (type) {
			case ACPI_VIDEO_DISPLAY_CRT:
				if (!video_device->flags.crt)
					continue;
				break;
			case ACPI_VIDEO_DISPLAY_TV:
				if (!video_device->flags.tvout)
					continue;
				break;
			case ACPI_VIDEO_DISPLAY_DVI:
				if (!video_device->flags.dvi)
					continue;
				break;
			case ACPI_VIDEO_DISPLAY_LCD:
				if (!video_device->flags.lcd)
					continue;
				break;
			}
		} else if (video_device->device_id != device_id) {
			continue;
		}

		status = acpi_video_device_EDID(video_device, &buffer, length);

		if (ACPI_FAILURE(status) || !buffer ||
		    buffer->type != ACPI_TYPE_BUFFER) {
			length = 128;
			status = acpi_video_device_EDID(video_device, &buffer,
							length);
			if (ACPI_FAILURE(status) || !buffer ||
			    buffer->type != ACPI_TYPE_BUFFER) {
				continue;
			}
		}

		*edid = buffer->buffer.pointer;
		return length;
	}

	return -ENODEV;
}
EXPORT_SYMBOL(acpi_video_get_edid);

static int
acpi_video_bus_get_devices(struct acpi_video_bus *video,
			   struct acpi_device *device)
{
	int status = 0;
	struct acpi_device *dev;

	/*
	 * There are systems where video module known to work fine regardless
	 * of broken _DOD and ignoring returned value here doesn't cause
	 * any issues later.
	 */
	acpi_video_device_enumerate(video);

	list_for_each_entry(dev, &device->children, node) {

		status = acpi_video_bus_get_one_device(dev, video);
		if (status) {
			dev_err(&dev->dev, "Can't attach device\n");
			break;
		}
		video->child_count++;
	}
	return status;
}

/* acpi_video interface */

/*
 * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
 * preform any automatic brightness change on receiving a notification.
 */
static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
{
	return acpi_video_bus_DOS(video, 0,
				  acpi_osi_is_win8() ? 1 : 0);
}

static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
{
	return acpi_video_bus_DOS(video, 0,
				  acpi_osi_is_win8() ? 0 : 1);
}

static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
{
	struct acpi_video_bus *video = acpi_driver_data(device);
	struct input_dev *input;
	int keycode = 0;

	if (!video || !video->input)
		return;

	input = video->input;

	switch (event) {
	case ACPI_VIDEO_NOTIFY_SWITCH:	/* User requested a switch,
					 * most likely via hotkey. */
		keycode = KEY_SWITCHVIDEOMODE;
		break;

	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
					 * connector. */
		acpi_video_device_enumerate(video);
		acpi_video_device_rebind(video);
		keycode = KEY_SWITCHVIDEOMODE;
		break;

	case ACPI_VIDEO_NOTIFY_CYCLE:	/* Cycle Display output hotkey pressed. */
		keycode = KEY_SWITCHVIDEOMODE;
		break;
	case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:	/* Next Display output hotkey pressed. */
		keycode = KEY_VIDEO_NEXT;
		break;
	case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:	/* previous Display output hotkey pressed. */
		keycode = KEY_VIDEO_PREV;
		break;

	default:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Unsupported event [0x%x]\n", event));
		break;
	}

	if (acpi_notifier_call_chain(device, event, 0))
		/* Something vetoed the keypress. */
		keycode = 0;

	if (keycode && (report_key_events & REPORT_OUTPUT_KEY_EVENTS)) {
		input_report_key(input, keycode, 1);
		input_sync(input);
		input_report_key(input, keycode, 0);
		input_sync(input);
	}

	return;
}

static void brightness_switch_event(struct acpi_video_device *video_device,
				    u32 event)
{
	if (!brightness_switch_enabled)
		return;

	video_device->switch_brightness_event = event;
	schedule_delayed_work(&video_device->switch_brightness_work, HZ / 10);
}

static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
{
	struct acpi_video_device *video_device = data;
	struct acpi_device *device = NULL;
	struct acpi_video_bus *bus;
	struct input_dev *input;
	int keycode = 0;

	if (!video_device)
		return;

	device = video_device->dev;
	bus = video_device->video;
	input = bus->input;

	switch (event) {
	case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:	/* Cycle brightness */
		brightness_switch_event(video_device, event);
		keycode = KEY_BRIGHTNESS_CYCLE;
		break;
	case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:	/* Increase brightness */
		brightness_switch_event(video_device, event);
		keycode = KEY_BRIGHTNESSUP;
		break;
	case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:	/* Decrease brightness */
		brightness_switch_event(video_device, event);
		keycode = KEY_BRIGHTNESSDOWN;
		break;
	case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:	/* zero brightness */
		brightness_switch_event(video_device, event);
		keycode = KEY_BRIGHTNESS_ZERO;
		break;
	case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:	/* display device off */
		brightness_switch_event(video_device, event);
		keycode = KEY_DISPLAY_OFF;
		break;
	default:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
				  "Unsupported event [0x%x]\n", event));
		break;
	}

	acpi_notifier_call_chain(device, event, 0);

	if (keycode && (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS)) {
		input_report_key(input, keycode, 1);
		input_sync(input);
		input_report_key(input, keycode, 0);
		input_sync(input);
	}

	return;
}

static int acpi_video_resume(struct notifier_block *nb,
				unsigned long val, void *ign)
{
	struct acpi_video_bus *video;
	struct acpi_video_device *video_device;
	int i;

	switch (val) {
	case PM_HIBERNATION_PREPARE:
	case PM_SUSPEND_PREPARE:
	case PM_RESTORE_PREPARE:
		return NOTIFY_DONE;
	}

	video = container_of(nb, struct acpi_video_bus, pm_nb);

	dev_info(&video->device->dev, "Restoring backlight state\n");

	for (i = 0; i < video->attached_count; i++) {
		video_device = video->attached_array[i].bind_info;
		if (video_device && video_device->brightness)
			acpi_video_device_lcd_set_level(video_device,
					video_device->brightness->curr);
	}

	return NOTIFY_OK;
}

static acpi_status
acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
			void **return_value)
{
	struct acpi_device *device = context;
	struct acpi_device *sibling;
	int result;

	if (handle == device->handle)
		return AE_CTRL_TERMINATE;

	result = acpi_bus_get_device(handle, &sibling);
	if (result)
		return AE_OK;

	if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
			return AE_ALREADY_EXISTS;

	return AE_OK;
}

static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
{
	struct backlight_properties props;
	struct pci_dev *pdev;
	acpi_handle acpi_parent;
	struct device *parent = NULL;
	int result;
	static int count;
	char *name;

	result = acpi_video_init_brightness(device);
	if (result)
		return;

	if (disable_backlight_sysfs_if > 0)
		return;

	name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
	if (!name)
		return;
	count++;

	acpi_get_parent(device->dev->handle, &acpi_parent);

	pdev = acpi_get_pci_dev(acpi_parent);
	if (pdev) {
		parent = &pdev->dev;
		pci_dev_put(pdev);
	}

	memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_FIRMWARE;
	props.max_brightness =
		device->brightness->count - ACPI_VIDEO_FIRST_LEVEL - 1;
	device->backlight = backlight_device_register(name,
						      parent,
						      device,
						      &acpi_backlight_ops,
						      &props);
	kfree(name);
	if (IS_ERR(device->backlight)) {
		device->backlight = NULL;
		return;
	}

	/*
	 * Save current brightness level in case we have to restore it
	 * before acpi_video_device_lcd_set_level() is called next time.
	 */
	device->backlight->props.brightness =
			acpi_video_get_brightness(device->backlight);

	device->cooling_dev = thermal_cooling_device_register("LCD",
				device->dev, &video_cooling_ops);
	if (IS_ERR(device->cooling_dev)) {
		/*
		 * Set cooling_dev to NULL so we don't crash trying to free it.
		 * Also, why the hell we are returning early and not attempt to
		 * register video output if cooling device registration failed?
		 * -- dtor
		 */
		device->cooling_dev = NULL;
		return;
	}

	dev_info(&device->dev->dev, "registered as cooling_device%d\n",
		 device->cooling_dev->id);
	result = sysfs_create_link(&device->dev->dev.kobj,
			&device->cooling_dev->device.kobj,
			"thermal_cooling");
	if (result)
		printk(KERN_ERR PREFIX "Create sysfs link\n");
	result = sysfs_create_link(&device->cooling_dev->device.kobj,
			&device->dev->dev.kobj, "device");
	if (result)
		printk(KERN_ERR PREFIX "Create sysfs link\n");
}

static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev;
	union acpi_object *levels;

	mutex_lock(&video->device_list_lock);
	list_for_each_entry(dev, &video->video_device_list, entry) {
		if (!acpi_video_device_lcd_query_levels(dev->dev->handle, &levels))
			kfree(levels);
	}
	mutex_unlock(&video->device_list_lock);
}

static bool acpi_video_should_register_backlight(struct acpi_video_device *dev)
{
	/*
	 * Do not create backlight device for video output
	 * device that is not in the enumerated list.
	 */
	if (!acpi_video_device_in_dod(dev)) {
		dev_dbg(&dev->dev->dev, "not in _DOD list, ignore\n");
		return false;
	}

	if (only_lcd)
		return dev->flags.lcd;
	return true;
}

static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev;

	if (video->backlight_registered)
		return 0;

	acpi_video_run_bcl_for_osi(video);

	if (acpi_video_get_backlight_type() != acpi_backlight_video)
		return 0;

	mutex_lock(&video->device_list_lock);
	list_for_each_entry(dev, &video->video_device_list, entry) {
		if (acpi_video_should_register_backlight(dev))
			acpi_video_dev_register_backlight(dev);
	}
	mutex_unlock(&video->device_list_lock);

	video->backlight_registered = true;

	video->pm_nb.notifier_call = acpi_video_resume;
	video->pm_nb.priority = 0;
	return register_pm_notifier(&video->pm_nb);
}

static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
{
	if (device->backlight) {
		backlight_device_unregister(device->backlight);
		device->backlight = NULL;
	}
	if (device->brightness) {
		kfree(device->brightness->levels);
		kfree(device->brightness);
		device->brightness = NULL;
	}
	if (device->cooling_dev) {
		sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
		sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
		thermal_cooling_device_unregister(device->cooling_dev);
		device->cooling_dev = NULL;
	}
}

static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev;
	int error;

	if (!video->backlight_registered)
		return 0;

	error = unregister_pm_notifier(&video->pm_nb);

	mutex_lock(&video->device_list_lock);
	list_for_each_entry(dev, &video->video_device_list, entry)
		acpi_video_dev_unregister_backlight(dev);
	mutex_unlock(&video->device_list_lock);

	video->backlight_registered = false;

	return error;
}

static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
{
	acpi_status status;
	struct acpi_device *adev = device->dev;

	status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
					     acpi_video_device_notify, device);
	if (ACPI_FAILURE(status))
		dev_err(&adev->dev, "Error installing notify handler\n");
	else
		device->flags.notify = 1;
}

static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
{
	struct input_dev *input;
	struct acpi_video_device *dev;
	int error;

	video->input = input = input_allocate_device();
	if (!input) {
		error = -ENOMEM;
		goto out;
	}

	error = acpi_video_bus_start_devices(video);
	if (error)
		goto err_free_input;

	snprintf(video->phys, sizeof(video->phys),
			"%s/video/input0", acpi_device_hid(video->device));

	input->name = acpi_device_name(video->device);
	input->phys = video->phys;
	input->id.bustype = BUS_HOST;
	input->id.product = 0x06;
	input->dev.parent = &video->device->dev;
	input->evbit[0] = BIT(EV_KEY);
	set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
	set_bit(KEY_VIDEO_NEXT, input->keybit);
	set_bit(KEY_VIDEO_PREV, input->keybit);
	set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
	set_bit(KEY_BRIGHTNESSUP, input->keybit);
	set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
	set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
	set_bit(KEY_DISPLAY_OFF, input->keybit);

	error = input_register_device(input);
	if (error)
		goto err_stop_dev;

	mutex_lock(&video->device_list_lock);
	list_for_each_entry(dev, &video->video_device_list, entry)
		acpi_video_dev_add_notify_handler(dev);
	mutex_unlock(&video->device_list_lock);

	return 0;

err_stop_dev:
	acpi_video_bus_stop_devices(video);
err_free_input:
	input_free_device(input);
	video->input = NULL;
out:
	return error;
}

static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
{
	if (dev->flags.notify) {
		acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
					   acpi_video_device_notify);
		dev->flags.notify = 0;
	}
}

static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev;

	mutex_lock(&video->device_list_lock);
	list_for_each_entry(dev, &video->video_device_list, entry)
		acpi_video_dev_remove_notify_handler(dev);
	mutex_unlock(&video->device_list_lock);

	acpi_video_bus_stop_devices(video);
	input_unregister_device(video->input);
	video->input = NULL;
}

static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
{
	struct acpi_video_device *dev, *next;

	mutex_lock(&video->device_list_lock);
	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
		list_del(&dev->entry);
		kfree(dev);
	}
	mutex_unlock(&video->device_list_lock);

	return 0;
}

static int instance;

static int acpi_video_bus_add(struct acpi_device *device)
{
	struct acpi_video_bus *video;
	int error;
	acpi_status status;

	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
				device->parent->handle, 1,
				acpi_video_bus_match, NULL,
				device, NULL);
	if (status == AE_ALREADY_EXISTS) {
		printk(KERN_WARNING FW_BUG
			"Duplicate ACPI video bus devices for the"
			" same VGA controller, please try module "
			"parameter \"video.allow_duplicates=1\""
			"if the current driver doesn't work.\n");
		if (!allow_duplicates)
			return -ENODEV;
	}

	video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
	if (!video)
		return -ENOMEM;

	/* a hack to fix the duplicate name "VID" problem on T61 */
	if (!strcmp(device->pnp.bus_id, "VID")) {
		if (instance)
			device->pnp.bus_id[3] = '0' + instance;
		instance++;
	}
	/* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
	if (!strcmp(device->pnp.bus_id, "VGA")) {
		if (instance)
			device->pnp.bus_id[3] = '0' + instance;
		instance++;
	}

	video->device = device;
	strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
	strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
	device->driver_data = video;

	acpi_video_bus_find_cap(video);
	error = acpi_video_bus_check(video);
	if (error)
		goto err_free_video;

	mutex_init(&video->device_list_lock);
	INIT_LIST_HEAD(&video->video_device_list);

	error = acpi_video_bus_get_devices(video, device);
	if (error)
		goto err_put_video;

	printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
	       ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
	       video->flags.multihead ? "yes" : "no",
	       video->flags.rom ? "yes" : "no",
	       video->flags.post ? "yes" : "no");
	mutex_lock(&video_list_lock);
	list_add_tail(&video->entry, &video_bus_head);
	mutex_unlock(&video_list_lock);

	acpi_video_bus_register_backlight(video);
	acpi_video_bus_add_notify_handler(video);

	return 0;

err_put_video:
	acpi_video_bus_put_devices(video);
	kfree(video->attached_array);
err_free_video:
	kfree(video);
	device->driver_data = NULL;

	return error;
}

static int acpi_video_bus_remove(struct acpi_device *device)
{
	struct acpi_video_bus *video = NULL;


	if (!device || !acpi_driver_data(device))
		return -EINVAL;

	video = acpi_driver_data(device);

	acpi_video_bus_remove_notify_handler(video);
	acpi_video_bus_unregister_backlight(video);
	acpi_video_bus_put_devices(video);

	mutex_lock(&video_list_lock);
	list_del(&video->entry);
	mutex_unlock(&video_list_lock);

	kfree(video->attached_array);
	kfree(video);

	return 0;
}

static int __init is_i740(struct pci_dev *dev)
{
	if (dev->device == 0x00D1)
		return 1;
	if (dev->device == 0x7000)
		return 1;
	return 0;
}

static int __init intel_opregion_present(void)
{
	int opregion = 0;
	struct pci_dev *dev = NULL;
	u32 address;

	for_each_pci_dev(dev) {
		if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
			continue;
		if (dev->vendor != PCI_VENDOR_ID_INTEL)
			continue;
		/* We don't want to poke around undefined i740 registers */
		if (is_i740(dev))
			continue;
		pci_read_config_dword(dev, 0xfc, &address);
		if (!address)
			continue;
		opregion = 1;
	}
	return opregion;
}

int acpi_video_register(void)
{
	int ret = 0;

	mutex_lock(&register_count_mutex);
	if (register_count) {
		/*
		 * if the function of acpi_video_register is already called,
		 * don't register the acpi_vide_bus again and return no error.
		 */
		goto leave;
	}

	dmi_check_system(video_dmi_table);

	ret = acpi_bus_register_driver(&acpi_video_bus);
	if (ret)
		goto leave;

	/*
	 * When the acpi_video_bus is loaded successfully, increase
	 * the counter reference.
	 */
	register_count = 1;

leave:
	mutex_unlock(&register_count_mutex);
	return ret;
}
EXPORT_SYMBOL(acpi_video_register);

void acpi_video_unregister(void)
{
	mutex_lock(&register_count_mutex);
	if (register_count) {
		acpi_bus_unregister_driver(&acpi_video_bus);
		register_count = 0;
	}
	mutex_unlock(&register_count_mutex);
}
EXPORT_SYMBOL(acpi_video_unregister);

void acpi_video_unregister_backlight(void)
{
	struct acpi_video_bus *video;

	mutex_lock(&register_count_mutex);
	if (register_count) {
		mutex_lock(&video_list_lock);
		list_for_each_entry(video, &video_bus_head, entry)
			acpi_video_bus_unregister_backlight(video);
		mutex_unlock(&video_list_lock);
	}
	mutex_unlock(&register_count_mutex);
}

bool acpi_video_handles_brightness_key_presses(void)
{
	bool have_video_busses;

	mutex_lock(&video_list_lock);
	have_video_busses = !list_empty(&video_bus_head);
	mutex_unlock(&video_list_lock);

	return have_video_busses &&
	       (report_key_events & REPORT_BRIGHTNESS_KEY_EVENTS);
}
EXPORT_SYMBOL(acpi_video_handles_brightness_key_presses);

/*
 * This is kind of nasty. Hardware using Intel chipsets may require
 * the video opregion code to be run first in order to initialise
 * state before any ACPI video calls are made. To handle this we defer
 * registration of the video class until the opregion code has run.
 */

static int __init acpi_video_init(void)
{
	/*
	 * Let the module load even if ACPI is disabled (e.g. due to
	 * a broken BIOS) so that i915.ko can still be loaded on such
	 * old systems without an AcpiOpRegion.
	 *
	 * acpi_video_register() will report -ENODEV later as well due
	 * to acpi_disabled when i915.ko tries to register itself afterwards.
	 */
	if (acpi_disabled)
		return 0;

	if (intel_opregion_present())
		return 0;

	return acpi_video_register();
}

static void __exit acpi_video_exit(void)
{
	acpi_video_detect_exit();
	acpi_video_unregister();

	return;
}

module_init(acpi_video_init);
module_exit(acpi_video_exit);