summaryrefslogtreecommitdiff
path: root/sound/usb/quirks.c
blob: fca72730a802ec617f267e858390babe37c56053 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/midi.h>
#include <linux/bits.h>

#include <sound/control.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>

#include "usbaudio.h"
#include "card.h"
#include "mixer.h"
#include "mixer_quirks.h"
#include "midi.h"
#include "quirks.h"
#include "helper.h"
#include "endpoint.h"
#include "pcm.h"
#include "clock.h"
#include "stream.h"

/*
 * handle the quirks for the contained interfaces
 */
static int create_composite_quirk(struct snd_usb_audio *chip,
				  struct usb_interface *iface,
				  struct usb_driver *driver,
				  const struct snd_usb_audio_quirk *quirk_comp)
{
	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
	const struct snd_usb_audio_quirk *quirk;
	int err;

	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
		if (!iface)
			continue;
		if (quirk->ifnum != probed_ifnum &&
		    usb_interface_claimed(iface))
			continue;
		err = snd_usb_create_quirk(chip, iface, driver, quirk);
		if (err < 0)
			return err;
	}

	for (quirk = quirk_comp->data; quirk->ifnum >= 0; ++quirk) {
		iface = usb_ifnum_to_if(chip->dev, quirk->ifnum);
		if (!iface)
			continue;
		if (quirk->ifnum != probed_ifnum &&
		    !usb_interface_claimed(iface))
			usb_driver_claim_interface(driver, iface, (void *)-1L);
	}

	return 0;
}

static int ignore_interface_quirk(struct snd_usb_audio *chip,
				  struct usb_interface *iface,
				  struct usb_driver *driver,
				  const struct snd_usb_audio_quirk *quirk)
{
	return 0;
}


/*
 * Allow alignment on audio sub-slot (channel samples) rather than
 * on audio slots (audio frames)
 */
static int create_align_transfer_quirk(struct snd_usb_audio *chip,
				       struct usb_interface *iface,
				       struct usb_driver *driver,
				       const struct snd_usb_audio_quirk *quirk)
{
	chip->txfr_quirk = 1;
	return 1;	/* Continue with creating streams and mixer */
}

static int create_any_midi_quirk(struct snd_usb_audio *chip,
				 struct usb_interface *intf,
				 struct usb_driver *driver,
				 const struct snd_usb_audio_quirk *quirk)
{
	return snd_usbmidi_create(chip->card, intf, &chip->midi_list, quirk);
}

/*
 * create a stream for an interface with proper descriptors
 */
static int create_standard_audio_quirk(struct snd_usb_audio *chip,
				       struct usb_interface *iface,
				       struct usb_driver *driver,
				       const struct snd_usb_audio_quirk *quirk)
{
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	int err;

	if (chip->usb_id == USB_ID(0x1686, 0x00dd)) /* Zoom R16/24 */
		chip->tx_length_quirk = 1;

	alts = &iface->altsetting[0];
	altsd = get_iface_desc(alts);
	err = snd_usb_parse_audio_interface(chip, altsd->bInterfaceNumber);
	if (err < 0) {
		usb_audio_err(chip, "cannot setup if %d: error %d\n",
			   altsd->bInterfaceNumber, err);
		return err;
	}
	/* reset the current interface */
	usb_set_interface(chip->dev, altsd->bInterfaceNumber, 0);
	return 0;
}

/*
 * create a stream for an endpoint/altsetting without proper descriptors
 */
static int create_fixed_stream_quirk(struct snd_usb_audio *chip,
				     struct usb_interface *iface,
				     struct usb_driver *driver,
				     const struct snd_usb_audio_quirk *quirk)
{
	struct audioformat *fp;
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	int stream, err;
	unsigned *rate_table = NULL;

	fp = kmemdup(quirk->data, sizeof(*fp), GFP_KERNEL);
	if (!fp)
		return -ENOMEM;

	INIT_LIST_HEAD(&fp->list);
	if (fp->nr_rates > MAX_NR_RATES) {
		kfree(fp);
		return -EINVAL;
	}
	if (fp->nr_rates > 0) {
		rate_table = kmemdup(fp->rate_table,
				     sizeof(int) * fp->nr_rates, GFP_KERNEL);
		if (!rate_table) {
			kfree(fp);
			return -ENOMEM;
		}
		fp->rate_table = rate_table;
	}

	stream = (fp->endpoint & USB_DIR_IN)
		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
	err = snd_usb_add_audio_stream(chip, stream, fp);
	if (err < 0)
		goto error;
	if (fp->iface != get_iface_desc(&iface->altsetting[0])->bInterfaceNumber ||
	    fp->altset_idx >= iface->num_altsetting) {
		err = -EINVAL;
		goto error;
	}
	alts = &iface->altsetting[fp->altset_idx];
	altsd = get_iface_desc(alts);
	if (altsd->bNumEndpoints < 1) {
		err = -EINVAL;
		goto error;
	}

	fp->protocol = altsd->bInterfaceProtocol;

	if (fp->datainterval == 0)
		fp->datainterval = snd_usb_parse_datainterval(chip, alts);
	if (fp->maxpacksize == 0)
		fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
	usb_set_interface(chip->dev, fp->iface, 0);
	snd_usb_init_pitch(chip, fp->iface, alts, fp);
	snd_usb_init_sample_rate(chip, fp->iface, alts, fp, fp->rate_max);
	return 0;

 error:
	list_del(&fp->list); /* unlink for avoiding double-free */
	kfree(fp);
	kfree(rate_table);
	return err;
}

static int create_auto_pcm_quirk(struct snd_usb_audio *chip,
				 struct usb_interface *iface,
				 struct usb_driver *driver)
{
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	struct usb_endpoint_descriptor *epd;
	struct uac1_as_header_descriptor *ashd;
	struct uac_format_type_i_discrete_descriptor *fmtd;

	/*
	 * Most Roland/Yamaha audio streaming interfaces have more or less
	 * standard descriptors, but older devices might lack descriptors, and
	 * future ones might change, so ensure that we fail silently if the
	 * interface doesn't look exactly right.
	 */

	/* must have a non-zero altsetting for streaming */
	if (iface->num_altsetting < 2)
		return -ENODEV;
	alts = &iface->altsetting[1];
	altsd = get_iface_desc(alts);

	/* must have an isochronous endpoint for streaming */
	if (altsd->bNumEndpoints < 1)
		return -ENODEV;
	epd = get_endpoint(alts, 0);
	if (!usb_endpoint_xfer_isoc(epd))
		return -ENODEV;

	/* must have format descriptors */
	ashd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
				       UAC_AS_GENERAL);
	fmtd = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
				       UAC_FORMAT_TYPE);
	if (!ashd || ashd->bLength < 7 ||
	    !fmtd || fmtd->bLength < 8)
		return -ENODEV;

	return create_standard_audio_quirk(chip, iface, driver, NULL);
}

static int create_yamaha_midi_quirk(struct snd_usb_audio *chip,
				    struct usb_interface *iface,
				    struct usb_driver *driver,
				    struct usb_host_interface *alts)
{
	static const struct snd_usb_audio_quirk yamaha_midi_quirk = {
		.type = QUIRK_MIDI_YAMAHA
	};
	struct usb_midi_in_jack_descriptor *injd;
	struct usb_midi_out_jack_descriptor *outjd;

	/* must have some valid jack descriptors */
	injd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
				       NULL, USB_MS_MIDI_IN_JACK);
	outjd = snd_usb_find_csint_desc(alts->extra, alts->extralen,
					NULL, USB_MS_MIDI_OUT_JACK);
	if (!injd && !outjd)
		return -ENODEV;
	if ((injd && !snd_usb_validate_midi_desc(injd)) ||
	    (outjd && !snd_usb_validate_midi_desc(outjd)))
		return -ENODEV;
	if (injd && (injd->bLength < 5 ||
		     (injd->bJackType != USB_MS_EMBEDDED &&
		      injd->bJackType != USB_MS_EXTERNAL)))
		return -ENODEV;
	if (outjd && (outjd->bLength < 6 ||
		      (outjd->bJackType != USB_MS_EMBEDDED &&
		       outjd->bJackType != USB_MS_EXTERNAL)))
		return -ENODEV;
	return create_any_midi_quirk(chip, iface, driver, &yamaha_midi_quirk);
}

static int create_roland_midi_quirk(struct snd_usb_audio *chip,
				    struct usb_interface *iface,
				    struct usb_driver *driver,
				    struct usb_host_interface *alts)
{
	static const struct snd_usb_audio_quirk roland_midi_quirk = {
		.type = QUIRK_MIDI_ROLAND
	};
	u8 *roland_desc = NULL;

	/* might have a vendor-specific descriptor <06 24 F1 02 ...> */
	for (;;) {
		roland_desc = snd_usb_find_csint_desc(alts->extra,
						      alts->extralen,
						      roland_desc, 0xf1);
		if (!roland_desc)
			return -ENODEV;
		if (roland_desc[0] < 6 || roland_desc[3] != 2)
			continue;
		return create_any_midi_quirk(chip, iface, driver,
					     &roland_midi_quirk);
	}
}

static int create_std_midi_quirk(struct snd_usb_audio *chip,
				 struct usb_interface *iface,
				 struct usb_driver *driver,
				 struct usb_host_interface *alts)
{
	struct usb_ms_header_descriptor *mshd;
	struct usb_ms_endpoint_descriptor *msepd;

	/* must have the MIDIStreaming interface header descriptor*/
	mshd = (struct usb_ms_header_descriptor *)alts->extra;
	if (alts->extralen < 7 ||
	    mshd->bLength < 7 ||
	    mshd->bDescriptorType != USB_DT_CS_INTERFACE ||
	    mshd->bDescriptorSubtype != USB_MS_HEADER)
		return -ENODEV;
	/* must have the MIDIStreaming endpoint descriptor*/
	msepd = (struct usb_ms_endpoint_descriptor *)alts->endpoint[0].extra;
	if (alts->endpoint[0].extralen < 4 ||
	    msepd->bLength < 4 ||
	    msepd->bDescriptorType != USB_DT_CS_ENDPOINT ||
	    msepd->bDescriptorSubtype != UAC_MS_GENERAL ||
	    msepd->bNumEmbMIDIJack < 1 ||
	    msepd->bNumEmbMIDIJack > 16)
		return -ENODEV;

	return create_any_midi_quirk(chip, iface, driver, NULL);
}

static int create_auto_midi_quirk(struct snd_usb_audio *chip,
				  struct usb_interface *iface,
				  struct usb_driver *driver)
{
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	struct usb_endpoint_descriptor *epd;
	int err;

	alts = &iface->altsetting[0];
	altsd = get_iface_desc(alts);

	/* must have at least one bulk/interrupt endpoint for streaming */
	if (altsd->bNumEndpoints < 1)
		return -ENODEV;
	epd = get_endpoint(alts, 0);
	if (!usb_endpoint_xfer_bulk(epd) &&
	    !usb_endpoint_xfer_int(epd))
		return -ENODEV;

	switch (USB_ID_VENDOR(chip->usb_id)) {
	case 0x0499: /* Yamaha */
		err = create_yamaha_midi_quirk(chip, iface, driver, alts);
		if (err != -ENODEV)
			return err;
		break;
	case 0x0582: /* Roland */
		err = create_roland_midi_quirk(chip, iface, driver, alts);
		if (err != -ENODEV)
			return err;
		break;
	}

	return create_std_midi_quirk(chip, iface, driver, alts);
}

static int create_autodetect_quirk(struct snd_usb_audio *chip,
				   struct usb_interface *iface,
				   struct usb_driver *driver)
{
	int err;

	err = create_auto_pcm_quirk(chip, iface, driver);
	if (err == -ENODEV)
		err = create_auto_midi_quirk(chip, iface, driver);
	return err;
}

static int create_autodetect_quirks(struct snd_usb_audio *chip,
				    struct usb_interface *iface,
				    struct usb_driver *driver,
				    const struct snd_usb_audio_quirk *quirk)
{
	int probed_ifnum = get_iface_desc(iface->altsetting)->bInterfaceNumber;
	int ifcount, ifnum, err;

	err = create_autodetect_quirk(chip, iface, driver);
	if (err < 0)
		return err;

	/*
	 * ALSA PCM playback/capture devices cannot be registered in two steps,
	 * so we have to claim the other corresponding interface here.
	 */
	ifcount = chip->dev->actconfig->desc.bNumInterfaces;
	for (ifnum = 0; ifnum < ifcount; ifnum++) {
		if (ifnum == probed_ifnum || quirk->ifnum >= 0)
			continue;
		iface = usb_ifnum_to_if(chip->dev, ifnum);
		if (!iface ||
		    usb_interface_claimed(iface) ||
		    get_iface_desc(iface->altsetting)->bInterfaceClass !=
							USB_CLASS_VENDOR_SPEC)
			continue;

		err = create_autodetect_quirk(chip, iface, driver);
		if (err >= 0)
			usb_driver_claim_interface(driver, iface, (void *)-1L);
	}

	return 0;
}

/*
 * Create a stream for an Edirol UA-700/UA-25/UA-4FX interface.  
 * The only way to detect the sample rate is by looking at wMaxPacketSize.
 */
static int create_uaxx_quirk(struct snd_usb_audio *chip,
			     struct usb_interface *iface,
			     struct usb_driver *driver,
			     const struct snd_usb_audio_quirk *quirk)
{
	static const struct audioformat ua_format = {
		.formats = SNDRV_PCM_FMTBIT_S24_3LE,
		.channels = 2,
		.fmt_type = UAC_FORMAT_TYPE_I,
		.altsetting = 1,
		.altset_idx = 1,
		.rates = SNDRV_PCM_RATE_CONTINUOUS,
	};
	struct usb_host_interface *alts;
	struct usb_interface_descriptor *altsd;
	struct audioformat *fp;
	int stream, err;

	/* both PCM and MIDI interfaces have 2 or more altsettings */
	if (iface->num_altsetting < 2)
		return -ENXIO;
	alts = &iface->altsetting[1];
	altsd = get_iface_desc(alts);

	if (altsd->bNumEndpoints == 2) {
		static const struct snd_usb_midi_endpoint_info ua700_ep = {
			.out_cables = 0x0003,
			.in_cables  = 0x0003
		};
		static const struct snd_usb_audio_quirk ua700_quirk = {
			.type = QUIRK_MIDI_FIXED_ENDPOINT,
			.data = &ua700_ep
		};
		static const struct snd_usb_midi_endpoint_info uaxx_ep = {
			.out_cables = 0x0001,
			.in_cables  = 0x0001
		};
		static const struct snd_usb_audio_quirk uaxx_quirk = {
			.type = QUIRK_MIDI_FIXED_ENDPOINT,
			.data = &uaxx_ep
		};
		const struct snd_usb_audio_quirk *quirk =
			chip->usb_id == USB_ID(0x0582, 0x002b)
			? &ua700_quirk : &uaxx_quirk;
		return __snd_usbmidi_create(chip->card, iface,
					  &chip->midi_list, quirk,
					  chip->usb_id);
	}

	if (altsd->bNumEndpoints != 1)
		return -ENXIO;

	fp = kmemdup(&ua_format, sizeof(*fp), GFP_KERNEL);
	if (!fp)
		return -ENOMEM;

	fp->iface = altsd->bInterfaceNumber;
	fp->endpoint = get_endpoint(alts, 0)->bEndpointAddress;
	fp->ep_attr = get_endpoint(alts, 0)->bmAttributes;
	fp->datainterval = 0;
	fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize);
	INIT_LIST_HEAD(&fp->list);

	switch (fp->maxpacksize) {
	case 0x120:
		fp->rate_max = fp->rate_min = 44100;
		break;
	case 0x138:
	case 0x140:
		fp->rate_max = fp->rate_min = 48000;
		break;
	case 0x258:
	case 0x260:
		fp->rate_max = fp->rate_min = 96000;
		break;
	default:
		usb_audio_err(chip, "unknown sample rate\n");
		kfree(fp);
		return -ENXIO;
	}

	stream = (fp->endpoint & USB_DIR_IN)
		? SNDRV_PCM_STREAM_CAPTURE : SNDRV_PCM_STREAM_PLAYBACK;
	err = snd_usb_add_audio_stream(chip, stream, fp);
	if (err < 0) {
		list_del(&fp->list); /* unlink for avoiding double-free */
		kfree(fp);
		return err;
	}
	usb_set_interface(chip->dev, fp->iface, 0);
	return 0;
}

/*
 * Create a standard mixer for the specified interface.
 */
static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
				       struct usb_interface *iface,
				       struct usb_driver *driver,
				       const struct snd_usb_audio_quirk *quirk)
{
	if (quirk->ifnum < 0)
		return 0;

	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
}


static int setup_fmt_after_resume_quirk(struct snd_usb_audio *chip,
				       struct usb_interface *iface,
				       struct usb_driver *driver,
				       const struct snd_usb_audio_quirk *quirk)
{
	chip->setup_fmt_after_resume_quirk = 1;
	return 1;	/* Continue with creating streams and mixer */
}

/*
 * audio-interface quirks
 *
 * returns zero if no standard audio/MIDI parsing is needed.
 * returns a positive value if standard audio/midi interfaces are parsed
 * after this.
 * returns a negative value at error.
 */
int snd_usb_create_quirk(struct snd_usb_audio *chip,
			 struct usb_interface *iface,
			 struct usb_driver *driver,
			 const struct snd_usb_audio_quirk *quirk)
{
	typedef int (*quirk_func_t)(struct snd_usb_audio *,
				    struct usb_interface *,
				    struct usb_driver *,
				    const struct snd_usb_audio_quirk *);
	static const quirk_func_t quirk_funcs[] = {
		[QUIRK_IGNORE_INTERFACE] = ignore_interface_quirk,
		[QUIRK_COMPOSITE] = create_composite_quirk,
		[QUIRK_AUTODETECT] = create_autodetect_quirks,
		[QUIRK_MIDI_STANDARD_INTERFACE] = create_any_midi_quirk,
		[QUIRK_MIDI_FIXED_ENDPOINT] = create_any_midi_quirk,
		[QUIRK_MIDI_YAMAHA] = create_any_midi_quirk,
		[QUIRK_MIDI_ROLAND] = create_any_midi_quirk,
		[QUIRK_MIDI_MIDIMAN] = create_any_midi_quirk,
		[QUIRK_MIDI_NOVATION] = create_any_midi_quirk,
		[QUIRK_MIDI_RAW_BYTES] = create_any_midi_quirk,
		[QUIRK_MIDI_EMAGIC] = create_any_midi_quirk,
		[QUIRK_MIDI_CME] = create_any_midi_quirk,
		[QUIRK_MIDI_AKAI] = create_any_midi_quirk,
		[QUIRK_MIDI_FTDI] = create_any_midi_quirk,
		[QUIRK_MIDI_CH345] = create_any_midi_quirk,
		[QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
		[QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
		[QUIRK_AUDIO_EDIROL_UAXX] = create_uaxx_quirk,
		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
		[QUIRK_SETUP_FMT_AFTER_RESUME] = setup_fmt_after_resume_quirk,
	};

	if (quirk->type < QUIRK_TYPE_COUNT) {
		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
	} else {
		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
		return -ENXIO;
	}
}

/*
 * boot quirks
 */

#define EXTIGY_FIRMWARE_SIZE_OLD 794
#define EXTIGY_FIRMWARE_SIZE_NEW 483

static int snd_usb_extigy_boot_quirk(struct usb_device *dev, struct usb_interface *intf)
{
	struct usb_host_config *config = dev->actconfig;
	int err;

	if (le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_OLD ||
	    le16_to_cpu(get_cfg_desc(config)->wTotalLength) == EXTIGY_FIRMWARE_SIZE_NEW) {
		dev_dbg(&dev->dev, "sending Extigy boot sequence...\n");
		/* Send message to force it to reconnect with full interface. */
		err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev,0),
				      0x10, 0x43, 0x0001, 0x000a, NULL, 0);
		if (err < 0)
			dev_dbg(&dev->dev, "error sending boot message: %d\n", err);
		err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
				&dev->descriptor, sizeof(dev->descriptor));
		config = dev->actconfig;
		if (err < 0)
			dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);
		err = usb_reset_configuration(dev);
		if (err < 0)
			dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
		dev_dbg(&dev->dev, "extigy_boot: new boot length = %d\n",
			    le16_to_cpu(get_cfg_desc(config)->wTotalLength));
		return -ENODEV; /* quit this anyway */
	}
	return 0;
}

static int snd_usb_audigy2nx_boot_quirk(struct usb_device *dev)
{
	u8 buf = 1;

	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), 0x2a,
			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
			0, 0, &buf, 1);
	if (buf == 0) {
		snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0x29,
				USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_OTHER,
				1, 2000, NULL, 0);
		return -ENODEV;
	}
	return 0;
}

static int snd_usb_fasttrackpro_boot_quirk(struct usb_device *dev)
{
	int err;

	if (dev->actconfig->desc.bConfigurationValue == 1) {
		dev_info(&dev->dev,
			   "Fast Track Pro switching to config #2\n");
		/* This function has to be available by the usb core module.
		 * if it is not avialable the boot quirk has to be left out
		 * and the configuration has to be set by udev or hotplug
		 * rules
		 */
		err = usb_driver_set_configuration(dev, 2);
		if (err < 0)
			dev_dbg(&dev->dev,
				"error usb_driver_set_configuration: %d\n",
				err);
		/* Always return an error, so that we stop creating a device
		   that will just be destroyed and recreated with a new
		   configuration */
		return -ENODEV;
	} else
		dev_info(&dev->dev, "Fast Track Pro config OK\n");

	return 0;
}

/*
 * C-Media CM106/CM106+ have four 16-bit internal registers that are nicely
 * documented in the device's data sheet.
 */
static int snd_usb_cm106_write_int_reg(struct usb_device *dev, int reg, u16 value)
{
	u8 buf[4];
	buf[0] = 0x20;
	buf[1] = value & 0xff;
	buf[2] = (value >> 8) & 0xff;
	buf[3] = reg;
	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), USB_REQ_SET_CONFIGURATION,
			       USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
			       0, 0, &buf, 4);
}

static int snd_usb_cm106_boot_quirk(struct usb_device *dev)
{
	/*
	 * Enable line-out driver mode, set headphone source to front
	 * channels, enable stereo mic.
	 */
	return snd_usb_cm106_write_int_reg(dev, 2, 0x8004);
}

/*
 * CM6206 registers from the CM6206 datasheet rev 2.1
 */
#define CM6206_REG0_DMA_MASTER BIT(15)
#define CM6206_REG0_SPDIFO_RATE_48K (2 << 12)
#define CM6206_REG0_SPDIFO_RATE_96K (7 << 12)
/* Bit 4 thru 11 is the S/PDIF category code */
#define CM6206_REG0_SPDIFO_CAT_CODE_GENERAL (0 << 4)
#define CM6206_REG0_SPDIFO_EMPHASIS_CD BIT(3)
#define CM6206_REG0_SPDIFO_COPYRIGHT_NA BIT(2)
#define CM6206_REG0_SPDIFO_NON_AUDIO BIT(1)
#define CM6206_REG0_SPDIFO_PRO_FORMAT BIT(0)

#define CM6206_REG1_TEST_SEL_CLK BIT(14)
#define CM6206_REG1_PLLBIN_EN BIT(13)
#define CM6206_REG1_SOFT_MUTE_EN BIT(12)
#define CM6206_REG1_GPIO4_OUT BIT(11)
#define CM6206_REG1_GPIO4_OE BIT(10)
#define CM6206_REG1_GPIO3_OUT BIT(9)
#define CM6206_REG1_GPIO3_OE BIT(8)
#define CM6206_REG1_GPIO2_OUT BIT(7)
#define CM6206_REG1_GPIO2_OE BIT(6)
#define CM6206_REG1_GPIO1_OUT BIT(5)
#define CM6206_REG1_GPIO1_OE BIT(4)
#define CM6206_REG1_SPDIFO_INVALID BIT(3)
#define CM6206_REG1_SPDIF_LOOP_EN BIT(2)
#define CM6206_REG1_SPDIFO_DIS BIT(1)
#define CM6206_REG1_SPDIFI_MIX BIT(0)

#define CM6206_REG2_DRIVER_ON BIT(15)
#define CM6206_REG2_HEADP_SEL_SIDE_CHANNELS (0 << 13)
#define CM6206_REG2_HEADP_SEL_SURROUND_CHANNELS (1 << 13)
#define CM6206_REG2_HEADP_SEL_CENTER_SUBW (2 << 13)
#define CM6206_REG2_HEADP_SEL_FRONT_CHANNELS (3 << 13)
#define CM6206_REG2_MUTE_HEADPHONE_RIGHT BIT(12)
#define CM6206_REG2_MUTE_HEADPHONE_LEFT BIT(11)
#define CM6206_REG2_MUTE_REAR_SURROUND_RIGHT BIT(10)
#define CM6206_REG2_MUTE_REAR_SURROUND_LEFT BIT(9)
#define CM6206_REG2_MUTE_SIDE_SURROUND_RIGHT BIT(8)
#define CM6206_REG2_MUTE_SIDE_SURROUND_LEFT BIT(7)
#define CM6206_REG2_MUTE_SUBWOOFER BIT(6)
#define CM6206_REG2_MUTE_CENTER BIT(5)
#define CM6206_REG2_MUTE_RIGHT_FRONT BIT(3)
#define CM6206_REG2_MUTE_LEFT_FRONT BIT(3)
#define CM6206_REG2_EN_BTL BIT(2)
#define CM6206_REG2_MCUCLKSEL_1_5_MHZ (0)
#define CM6206_REG2_MCUCLKSEL_3_MHZ (1)
#define CM6206_REG2_MCUCLKSEL_6_MHZ (2)
#define CM6206_REG2_MCUCLKSEL_12_MHZ (3)

/* Bit 11..13 sets the sensitivity to FLY tuner volume control VP/VD signal */
#define CM6206_REG3_FLYSPEED_DEFAULT (2 << 11)
#define CM6206_REG3_VRAP25EN BIT(10)
#define CM6206_REG3_MSEL1 BIT(9)
#define CM6206_REG3_SPDIFI_RATE_44_1K BIT(0 << 7)
#define CM6206_REG3_SPDIFI_RATE_48K BIT(2 << 7)
#define CM6206_REG3_SPDIFI_RATE_32K BIT(3 << 7)
#define CM6206_REG3_PINSEL BIT(6)
#define CM6206_REG3_FOE BIT(5)
#define CM6206_REG3_ROE BIT(4)
#define CM6206_REG3_CBOE BIT(3)
#define CM6206_REG3_LOSE BIT(2)
#define CM6206_REG3_HPOE BIT(1)
#define CM6206_REG3_SPDIFI_CANREC BIT(0)

#define CM6206_REG5_DA_RSTN BIT(13)
#define CM6206_REG5_AD_RSTN BIT(12)
#define CM6206_REG5_SPDIFO_AD2SPDO BIT(12)
#define CM6206_REG5_SPDIFO_SEL_FRONT (0 << 9)
#define CM6206_REG5_SPDIFO_SEL_SIDE_SUR (1 << 9)
#define CM6206_REG5_SPDIFO_SEL_CEN_LFE (2 << 9)
#define CM6206_REG5_SPDIFO_SEL_REAR_SUR (3 << 9)
#define CM6206_REG5_CODECM BIT(8)
#define CM6206_REG5_EN_HPF BIT(7)
#define CM6206_REG5_T_SEL_DSDA4 BIT(6)
#define CM6206_REG5_T_SEL_DSDA3 BIT(5)
#define CM6206_REG5_T_SEL_DSDA2 BIT(4)
#define CM6206_REG5_T_SEL_DSDA1 BIT(3)
#define CM6206_REG5_T_SEL_DSDAD_NORMAL 0
#define CM6206_REG5_T_SEL_DSDAD_FRONT 4
#define CM6206_REG5_T_SEL_DSDAD_S_SURROUND 5
#define CM6206_REG5_T_SEL_DSDAD_CEN_LFE 6
#define CM6206_REG5_T_SEL_DSDAD_R_SURROUND 7

static int snd_usb_cm6206_boot_quirk(struct usb_device *dev)
{
	int err  = 0, reg;
	int val[] = {
		/*
		 * Values here are chosen based on sniffing USB traffic
		 * under Windows.
		 *
		 * REG0: DAC is master, sample rate 48kHz, no copyright
		 */
		CM6206_REG0_SPDIFO_RATE_48K |
		CM6206_REG0_SPDIFO_COPYRIGHT_NA,
		/*
		 * REG1: PLL binary search enable, soft mute enable.
		 */
		CM6206_REG1_PLLBIN_EN |
		CM6206_REG1_SOFT_MUTE_EN,
		/*
		 * REG2: enable output drivers,
		 * select front channels to the headphone output,
		 * then mute the headphone channels, run the MCU
		 * at 1.5 MHz.
		 */
		CM6206_REG2_DRIVER_ON |
		CM6206_REG2_HEADP_SEL_FRONT_CHANNELS |
		CM6206_REG2_MUTE_HEADPHONE_RIGHT |
		CM6206_REG2_MUTE_HEADPHONE_LEFT,
		/*
		 * REG3: default flyspeed, set 2.5V mic bias
		 * enable all line out ports and enable SPDIF
		 */
		CM6206_REG3_FLYSPEED_DEFAULT |
		CM6206_REG3_VRAP25EN |
		CM6206_REG3_FOE |
		CM6206_REG3_ROE |
		CM6206_REG3_CBOE |
		CM6206_REG3_LOSE |
		CM6206_REG3_HPOE |
		CM6206_REG3_SPDIFI_CANREC,
		/* REG4 is just a bunch of GPIO lines */
		0x0000,
		/* REG5: de-assert AD/DA reset signals */
		CM6206_REG5_DA_RSTN |
		CM6206_REG5_AD_RSTN };

	for (reg = 0; reg < ARRAY_SIZE(val); reg++) {
		err = snd_usb_cm106_write_int_reg(dev, reg, val[reg]);
		if (err < 0)
			return err;
	}

	return err;
}

/* quirk for Plantronics GameCom 780 with CM6302 chip */
static int snd_usb_gamecon780_boot_quirk(struct usb_device *dev)
{
	/* set the initial volume and don't change; other values are either
	 * too loud or silent due to firmware bug (bko#65251)
	 */
	u8 buf[2] = { 0x74, 0xe3 };
	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
			USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_OUT,
			UAC_FU_VOLUME << 8, 9 << 8, buf, 2);
}

/*
 * Novation Twitch DJ controller
 * Focusrite Novation Saffire 6 USB audio card
 */
static int snd_usb_novation_boot_quirk(struct usb_device *dev)
{
	/* preemptively set up the device because otherwise the
	 * raw MIDI endpoints are not active */
	usb_set_interface(dev, 0, 1);
	return 0;
}

/*
 * This call will put the synth in "USB send" mode, i.e it will send MIDI
 * messages through USB (this is disabled at startup). The synth will
 * acknowledge by sending a sysex on endpoint 0x85 and by displaying a USB
 * sign on its LCD. Values here are chosen based on sniffing USB traffic
 * under Windows.
 */
static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
{
	int err, actual_length;
	/* "midi send" enable */
	static const u8 seq[] = { 0x4e, 0x73, 0x52, 0x01 };
	void *buf;

	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x05)))
		return -EINVAL;
	buf = kmemdup(seq, ARRAY_SIZE(seq), GFP_KERNEL);
	if (!buf)
		return -ENOMEM;
	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x05), buf,
			ARRAY_SIZE(seq), &actual_length, 1000);
	kfree(buf);
	if (err < 0)
		return err;

	return 0;
}

/*
 * Some sound cards from Native Instruments are in fact compliant to the USB
 * audio standard of version 2 and other approved USB standards, even though
 * they come up as vendor-specific device when first connected.
 *
 * However, they can be told to come up with a new set of descriptors
 * upon their next enumeration, and the interfaces announced by the new
 * descriptors will then be handled by the kernel's class drivers. As the
 * product ID will also change, no further checks are required.
 */

static int snd_usb_nativeinstruments_boot_quirk(struct usb_device *dev)
{
	int ret;

	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
		return -EINVAL;
	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
				  0xaf, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
				  1, 0, NULL, 0, 1000);

	if (ret < 0)
		return ret;

	usb_reset_device(dev);

	/* return -EAGAIN, so the creation of an audio interface for this
	 * temporary device is aborted. The device will reconnect with a
	 * new product ID */
	return -EAGAIN;
}

static void mbox2_setup_48_24_magic(struct usb_device *dev)
{
	u8 srate[3];
	u8 temp[12];

	/* Choose 48000Hz permanently */
	srate[0] = 0x80;
	srate[1] = 0xbb;
	srate[2] = 0x00;

	/* Send the magic! */
	snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
		0x01, 0x22, 0x0100, 0x0085, &temp, 0x0003);
	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
		0x81, 0xa2, 0x0100, 0x0085, &srate, 0x0003);
	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
		0x81, 0xa2, 0x0100, 0x0086, &srate, 0x0003);
	snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
		0x81, 0xa2, 0x0100, 0x0003, &srate, 0x0003);
	return;
}

/* Digidesign Mbox 2 needs to load firmware onboard
 * and driver must wait a few seconds for initialisation.
 */

#define MBOX2_FIRMWARE_SIZE    646
#define MBOX2_BOOT_LOADING     0x01 /* Hard coded into the device */
#define MBOX2_BOOT_READY       0x02 /* Hard coded into the device */

static int snd_usb_mbox2_boot_quirk(struct usb_device *dev)
{
	struct usb_host_config *config = dev->actconfig;
	int err;
	u8 bootresponse[0x12];
	int fwsize;
	int count;

	fwsize = le16_to_cpu(get_cfg_desc(config)->wTotalLength);

	if (fwsize != MBOX2_FIRMWARE_SIZE) {
		dev_err(&dev->dev, "Invalid firmware size=%d.\n", fwsize);
		return -ENODEV;
	}

	dev_dbg(&dev->dev, "Sending Digidesign Mbox 2 boot sequence...\n");

	count = 0;
	bootresponse[0] = MBOX2_BOOT_LOADING;
	while ((bootresponse[0] == MBOX2_BOOT_LOADING) && (count < 10)) {
		msleep(500); /* 0.5 second delay */
		snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
			/* Control magic - load onboard firmware */
			0x85, 0xc0, 0x0001, 0x0000, &bootresponse, 0x0012);
		if (bootresponse[0] == MBOX2_BOOT_READY)
			break;
		dev_dbg(&dev->dev, "device not ready, resending boot sequence...\n");
		count++;
	}

	if (bootresponse[0] != MBOX2_BOOT_READY) {
		dev_err(&dev->dev, "Unknown bootresponse=%d, or timed out, ignoring device.\n", bootresponse[0]);
		return -ENODEV;
	}

	dev_dbg(&dev->dev, "device initialised!\n");

	err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
		&dev->descriptor, sizeof(dev->descriptor));
	config = dev->actconfig;
	if (err < 0)
		dev_dbg(&dev->dev, "error usb_get_descriptor: %d\n", err);

	err = usb_reset_configuration(dev);
	if (err < 0)
		dev_dbg(&dev->dev, "error usb_reset_configuration: %d\n", err);
	dev_dbg(&dev->dev, "mbox2_boot: new boot length = %d\n",
		le16_to_cpu(get_cfg_desc(config)->wTotalLength));

	mbox2_setup_48_24_magic(dev);

	dev_info(&dev->dev, "Digidesign Mbox 2: 24bit 48kHz");

	return 0; /* Successful boot */
}

static int snd_usb_axefx3_boot_quirk(struct usb_device *dev)
{
	int err;

	dev_dbg(&dev->dev, "Waiting for Axe-Fx III to boot up...\n");

	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
		return -EINVAL;
	/* If the Axe-Fx III has not fully booted, it will timeout when trying
	 * to enable the audio streaming interface. A more generous timeout is
	 * used here to detect when the Axe-Fx III has finished booting as the
	 * set interface message will be acked once it has
	 */
	err = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
				USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
				1, 1, NULL, 0, 120000);
	if (err < 0) {
		dev_err(&dev->dev,
			"failed waiting for Axe-Fx III to boot: %d\n", err);
		return err;
	}

	dev_dbg(&dev->dev, "Axe-Fx III is now ready\n");

	err = usb_set_interface(dev, 1, 0);
	if (err < 0)
		dev_dbg(&dev->dev,
			"error stopping Axe-Fx III interface: %d\n", err);

	return 0;
}


#define MICROBOOK_BUF_SIZE 128

static int snd_usb_motu_microbookii_communicate(struct usb_device *dev, u8 *buf,
						int buf_size, int *length)
{
	int err, actual_length;

	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x01)))
		return -EINVAL;
	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x01), buf, *length,
				&actual_length, 1000);
	if (err < 0)
		return err;

	print_hex_dump(KERN_DEBUG, "MicroBookII snd: ", DUMP_PREFIX_NONE, 16, 1,
		       buf, actual_length, false);

	memset(buf, 0, buf_size);

	if (snd_usb_pipe_sanity_check(dev, usb_rcvintpipe(dev, 0x82)))
		return -EINVAL;
	err = usb_interrupt_msg(dev, usb_rcvintpipe(dev, 0x82), buf, buf_size,
				&actual_length, 1000);
	if (err < 0)
		return err;

	print_hex_dump(KERN_DEBUG, "MicroBookII rcv: ", DUMP_PREFIX_NONE, 16, 1,
		       buf, actual_length, false);

	*length = actual_length;
	return 0;
}

static int snd_usb_motu_microbookii_boot_quirk(struct usb_device *dev)
{
	int err, actual_length, poll_attempts = 0;
	static const u8 set_samplerate_seq[] = { 0x00, 0x00, 0x00, 0x00,
						 0x00, 0x00, 0x0b, 0x14,
						 0x00, 0x00, 0x00, 0x01 };
	static const u8 poll_ready_seq[] = { 0x00, 0x04, 0x00, 0x00,
					     0x00, 0x00, 0x0b, 0x18 };
	u8 *buf = kzalloc(MICROBOOK_BUF_SIZE, GFP_KERNEL);

	if (!buf)
		return -ENOMEM;

	dev_info(&dev->dev, "Waiting for MOTU Microbook II to boot up...\n");

	/* First we tell the device which sample rate to use. */
	memcpy(buf, set_samplerate_seq, sizeof(set_samplerate_seq));
	actual_length = sizeof(set_samplerate_seq);
	err = snd_usb_motu_microbookii_communicate(dev, buf, MICROBOOK_BUF_SIZE,
						   &actual_length);

	if (err < 0) {
		dev_err(&dev->dev,
			"failed setting the sample rate for Motu MicroBook II: %d\n",
			err);
		goto free_buf;
	}

	/* Then we poll every 100 ms until the device informs of its readiness. */
	while (true) {
		if (++poll_attempts > 100) {
			dev_err(&dev->dev,
				"failed booting Motu MicroBook II: timeout\n");
			err = -ENODEV;
			goto free_buf;
		}

		memset(buf, 0, MICROBOOK_BUF_SIZE);
		memcpy(buf, poll_ready_seq, sizeof(poll_ready_seq));

		actual_length = sizeof(poll_ready_seq);
		err = snd_usb_motu_microbookii_communicate(
			dev, buf, MICROBOOK_BUF_SIZE, &actual_length);
		if (err < 0) {
			dev_err(&dev->dev,
				"failed booting Motu MicroBook II: communication error %d\n",
				err);
			goto free_buf;
		}

		/* the device signals its readiness through a message of the
		 * form
		 *           XX 06 00 00 00 00 0b 18  00 00 00 01
		 * If the device is not yet ready to accept audio data, the
		 * last byte of that sequence is 00.
		 */
		if (actual_length == 12 && buf[actual_length - 1] == 1)
			break;

		msleep(100);
	}

	dev_info(&dev->dev, "MOTU MicroBook II ready\n");

free_buf:
	kfree(buf);
	return err;
}

static int snd_usb_motu_m_series_boot_quirk(struct usb_device *dev)
{
	int ret;

	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
		return -EINVAL;
	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			      1, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      0x0, 0, NULL, 0, 1000);

	if (ret < 0)
		return ret;

	msleep(2000);

	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			      1, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			      0x20, 0, NULL, 0, 1000);

	if (ret < 0)
		return ret;

	return 0;
}

/*
 * Setup quirks
 */
#define MAUDIO_SET		0x01 /* parse device_setup */
#define MAUDIO_SET_COMPATIBLE	0x80 /* use only "win-compatible" interfaces */
#define MAUDIO_SET_DTS		0x02 /* enable DTS Digital Output */
#define MAUDIO_SET_96K		0x04 /* 48-96KHz rate if set, 8-48KHz otherwise */
#define MAUDIO_SET_24B		0x08 /* 24bits sample if set, 16bits otherwise */
#define MAUDIO_SET_DI		0x10 /* enable Digital Input */
#define MAUDIO_SET_MASK		0x1f /* bit mask for setup value */
#define MAUDIO_SET_24B_48K_DI	 0x19 /* 24bits+48KHz+Digital Input */
#define MAUDIO_SET_24B_48K_NOTDI 0x09 /* 24bits+48KHz+No Digital Input */
#define MAUDIO_SET_16B_48K_DI	 0x11 /* 16bits+48KHz+Digital Input */
#define MAUDIO_SET_16B_48K_NOTDI 0x01 /* 16bits+48KHz+No Digital Input */

static int quattro_skip_setting_quirk(struct snd_usb_audio *chip,
				      int iface, int altno)
{
	/* Reset ALL ifaces to 0 altsetting.
	 * Call it for every possible altsetting of every interface.
	 */
	usb_set_interface(chip->dev, iface, 0);
	if (chip->setup & MAUDIO_SET) {
		if (chip->setup & MAUDIO_SET_COMPATIBLE) {
			if (iface != 1 && iface != 2)
				return 1; /* skip all interfaces but 1 and 2 */
		} else {
			unsigned int mask;
			if (iface == 1 || iface == 2)
				return 1; /* skip interfaces 1 and 2 */
			if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
				return 1; /* skip this altsetting */
			mask = chip->setup & MAUDIO_SET_MASK;
			if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
				return 1; /* skip this altsetting */
			if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
				return 1; /* skip this altsetting */
			if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 4)
				return 1; /* skip this altsetting */
		}
	}
	usb_audio_dbg(chip,
		    "using altsetting %d for interface %d config %d\n",
		    altno, iface, chip->setup);
	return 0; /* keep this altsetting */
}

static int audiophile_skip_setting_quirk(struct snd_usb_audio *chip,
					 int iface,
					 int altno)
{
	/* Reset ALL ifaces to 0 altsetting.
	 * Call it for every possible altsetting of every interface.
	 */
	usb_set_interface(chip->dev, iface, 0);

	if (chip->setup & MAUDIO_SET) {
		unsigned int mask;
		if ((chip->setup & MAUDIO_SET_DTS) && altno != 6)
			return 1; /* skip this altsetting */
		if ((chip->setup & MAUDIO_SET_96K) && altno != 1)
			return 1; /* skip this altsetting */
		mask = chip->setup & MAUDIO_SET_MASK;
		if (mask == MAUDIO_SET_24B_48K_DI && altno != 2)
			return 1; /* skip this altsetting */
		if (mask == MAUDIO_SET_24B_48K_NOTDI && altno != 3)
			return 1; /* skip this altsetting */
		if (mask == MAUDIO_SET_16B_48K_DI && altno != 4)
			return 1; /* skip this altsetting */
		if (mask == MAUDIO_SET_16B_48K_NOTDI && altno != 5)
			return 1; /* skip this altsetting */
	}

	return 0; /* keep this altsetting */
}

static int fasttrackpro_skip_setting_quirk(struct snd_usb_audio *chip,
					   int iface, int altno)
{
	/* Reset ALL ifaces to 0 altsetting.
	 * Call it for every possible altsetting of every interface.
	 */
	usb_set_interface(chip->dev, iface, 0);

	/* possible configuration where both inputs and only one output is
	 *used is not supported by the current setup
	 */
	if (chip->setup & (MAUDIO_SET | MAUDIO_SET_24B)) {
		if (chip->setup & MAUDIO_SET_96K) {
			if (altno != 3 && altno != 6)
				return 1;
		} else if (chip->setup & MAUDIO_SET_DI) {
			if (iface == 4)
				return 1; /* no analog input */
			if (altno != 2 && altno != 5)
				return 1; /* enable only altsets 2 and 5 */
		} else {
			if (iface == 5)
				return 1; /* disable digialt input */
			if (altno != 2 && altno != 5)
				return 1; /* enalbe only altsets 2 and 5 */
		}
	} else {
		/* keep only 16-Bit mode */
		if (altno != 1)
			return 1;
	}

	usb_audio_dbg(chip,
		    "using altsetting %d for interface %d config %d\n",
		    altno, iface, chip->setup);
	return 0; /* keep this altsetting */
}

static int s1810c_skip_setting_quirk(struct snd_usb_audio *chip,
					   int iface, int altno)
{
	/*
	 * Altno settings:
	 *
	 * Playback (Interface 1):
	 * 1: 6 Analog + 2 S/PDIF
	 * 2: 6 Analog + 2 S/PDIF
	 * 3: 6 Analog
	 *
	 * Capture (Interface 2):
	 * 1: 8 Analog + 2 S/PDIF + 8 ADAT
	 * 2: 8 Analog + 2 S/PDIF + 4 ADAT
	 * 3: 8 Analog
	 */

	/*
	 * I'll leave 2 as the default one and
	 * use device_setup to switch to the
	 * other two.
	 */
	if ((chip->setup == 0 || chip->setup > 2) && altno != 2)
		return 1;
	else if (chip->setup == 1 && altno != 1)
		return 1;
	else if (chip->setup == 2 && altno != 3)
		return 1;

	return 0;
}

int snd_usb_apply_interface_quirk(struct snd_usb_audio *chip,
				  int iface,
				  int altno)
{
	/* audiophile usb: skip altsets incompatible with device_setup */
	if (chip->usb_id == USB_ID(0x0763, 0x2003))
		return audiophile_skip_setting_quirk(chip, iface, altno);
	/* quattro usb: skip altsets incompatible with device_setup */
	if (chip->usb_id == USB_ID(0x0763, 0x2001))
		return quattro_skip_setting_quirk(chip, iface, altno);
	/* fasttrackpro usb: skip altsets incompatible with device_setup */
	if (chip->usb_id == USB_ID(0x0763, 0x2012))
		return fasttrackpro_skip_setting_quirk(chip, iface, altno);
	/* presonus studio 1810c: skip altsets incompatible with device_setup */
	if (chip->usb_id == USB_ID(0x0194f, 0x010c))
		return s1810c_skip_setting_quirk(chip, iface, altno);


	return 0;
}

int snd_usb_apply_boot_quirk(struct usb_device *dev,
			     struct usb_interface *intf,
			     const struct snd_usb_audio_quirk *quirk,
			     unsigned int id)
{
	switch (id) {
	case USB_ID(0x041e, 0x3000):
		/* SB Extigy needs special boot-up sequence */
		/* if more models come, this will go to the quirk list. */
		return snd_usb_extigy_boot_quirk(dev, intf);

	case USB_ID(0x041e, 0x3020):
		/* SB Audigy 2 NX needs its own boot-up magic, too */
		return snd_usb_audigy2nx_boot_quirk(dev);

	case USB_ID(0x10f5, 0x0200):
		/* C-Media CM106 / Turtle Beach Audio Advantage Roadie */
		return snd_usb_cm106_boot_quirk(dev);

	case USB_ID(0x0d8c, 0x0102):
		/* C-Media CM6206 / CM106-Like Sound Device */
	case USB_ID(0x0ccd, 0x00b1): /* Terratec Aureon 7.1 USB */
		return snd_usb_cm6206_boot_quirk(dev);

	case USB_ID(0x0dba, 0x3000):
		/* Digidesign Mbox 2 */
		return snd_usb_mbox2_boot_quirk(dev);

	case USB_ID(0x1235, 0x0010): /* Focusrite Novation Saffire 6 USB */
	case USB_ID(0x1235, 0x0018): /* Focusrite Novation Twitch */
		return snd_usb_novation_boot_quirk(dev);

	case USB_ID(0x133e, 0x0815):
		/* Access Music VirusTI Desktop */
		return snd_usb_accessmusic_boot_quirk(dev);

	case USB_ID(0x17cc, 0x1000): /* Komplete Audio 6 */
	case USB_ID(0x17cc, 0x1010): /* Traktor Audio 6 */
	case USB_ID(0x17cc, 0x1020): /* Traktor Audio 10 */
		return snd_usb_nativeinstruments_boot_quirk(dev);
	case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
		return snd_usb_fasttrackpro_boot_quirk(dev);
	case USB_ID(0x047f, 0xc010): /* Plantronics Gamecom 780 */
		return snd_usb_gamecon780_boot_quirk(dev);
	case USB_ID(0x2466, 0x8010): /* Fractal Audio Axe-Fx 3 */
		return snd_usb_axefx3_boot_quirk(dev);
	case USB_ID(0x07fd, 0x0004): /* MOTU MicroBook II */
		/*
		 * For some reason interface 3 with vendor-spec class is
		 * detected on MicroBook IIc.
		 */
		if (get_iface_desc(intf->altsetting)->bInterfaceClass ==
		    USB_CLASS_VENDOR_SPEC &&
		    get_iface_desc(intf->altsetting)->bInterfaceNumber < 3)
			return snd_usb_motu_microbookii_boot_quirk(dev);
		break;
	}

	return 0;
}

int snd_usb_apply_boot_quirk_once(struct usb_device *dev,
				  struct usb_interface *intf,
				  const struct snd_usb_audio_quirk *quirk,
				  unsigned int id)
{
	switch (id) {
	case USB_ID(0x07fd, 0x0008): /* MOTU M Series */
		return snd_usb_motu_m_series_boot_quirk(dev);
	}

	return 0;
}

/*
 * check if the device uses big-endian samples
 */
int snd_usb_is_big_endian_format(struct snd_usb_audio *chip, struct audioformat *fp)
{
	/* it depends on altsetting whether the device is big-endian or not */
	switch (chip->usb_id) {
	case USB_ID(0x0763, 0x2001): /* M-Audio Quattro: captured data only */
		if (fp->altsetting == 2 || fp->altsetting == 3 ||
			fp->altsetting == 5 || fp->altsetting == 6)
			return 1;
		break;
	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
		if (chip->setup == 0x00 ||
			fp->altsetting == 1 || fp->altsetting == 2 ||
			fp->altsetting == 3)
			return 1;
		break;
	case USB_ID(0x0763, 0x2012): /* M-Audio Fast Track Pro */
		if (fp->altsetting == 2 || fp->altsetting == 3 ||
			fp->altsetting == 5 || fp->altsetting == 6)
			return 1;
		break;
	}
	return 0;
}

/*
 * For E-Mu 0404USB/0202USB/TrackerPre/0204 sample rate should be set for device,
 * not for interface.
 */

enum {
	EMU_QUIRK_SR_44100HZ = 0,
	EMU_QUIRK_SR_48000HZ,
	EMU_QUIRK_SR_88200HZ,
	EMU_QUIRK_SR_96000HZ,
	EMU_QUIRK_SR_176400HZ,
	EMU_QUIRK_SR_192000HZ
};

static void set_format_emu_quirk(struct snd_usb_substream *subs,
				 struct audioformat *fmt)
{
	unsigned char emu_samplerate_id = 0;

	/* When capture is active
	 * sample rate shouldn't be changed
	 * by playback substream
	 */
	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
		if (subs->stream->substream[SNDRV_PCM_STREAM_CAPTURE].interface != -1)
			return;
	}

	switch (fmt->rate_min) {
	case 48000:
		emu_samplerate_id = EMU_QUIRK_SR_48000HZ;
		break;
	case 88200:
		emu_samplerate_id = EMU_QUIRK_SR_88200HZ;
		break;
	case 96000:
		emu_samplerate_id = EMU_QUIRK_SR_96000HZ;
		break;
	case 176400:
		emu_samplerate_id = EMU_QUIRK_SR_176400HZ;
		break;
	case 192000:
		emu_samplerate_id = EMU_QUIRK_SR_192000HZ;
		break;
	default:
		emu_samplerate_id = EMU_QUIRK_SR_44100HZ;
		break;
	}
	snd_emuusb_set_samplerate(subs->stream->chip, emu_samplerate_id);
	subs->pkt_offset_adj = (emu_samplerate_id >= EMU_QUIRK_SR_176400HZ) ? 4 : 0;
}


/*
 * Pioneer DJ DJM-900NXS2
 * Device needs to know the sample rate each time substream is started
 */
static int pioneer_djm_set_format_quirk(struct snd_usb_substream *subs)
{

	/* Convert sample rate value to little endian */
	u8 sr[3];

	sr[0] = subs->cur_rate & 0xff;
	sr[1] = (subs->cur_rate >> 8) & 0xff;
	sr[2] = (subs->cur_rate >> 16) & 0xff;

	/* Configure device */
	usb_set_interface(subs->dev, 0, 1);
	snd_usb_ctl_msg(subs->stream->chip->dev,
		usb_rcvctrlpipe(subs->stream->chip->dev, 0),
		0x01, 0x22, 0x0100, 0x0082, &sr, 0x0003);

	return 0;
}

void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
			      struct audioformat *fmt)
{
	switch (subs->stream->chip->usb_id) {
	case USB_ID(0x041e, 0x3f02): /* E-Mu 0202 USB */
	case USB_ID(0x041e, 0x3f04): /* E-Mu 0404 USB */
	case USB_ID(0x041e, 0x3f0a): /* E-Mu Tracker Pre */
	case USB_ID(0x041e, 0x3f19): /* E-Mu 0204 USB */
		set_format_emu_quirk(subs, fmt);
		break;
	case USB_ID(0x2b73, 0x000a): /* Pioneer DJ DJM-900NXS2 */
		pioneer_djm_set_format_quirk(subs);
		break;
	}
}

bool snd_usb_get_sample_rate_quirk(struct snd_usb_audio *chip)
{
	/* devices which do not support reading the sample rate. */
	switch (chip->usb_id) {
	case USB_ID(0x041e, 0x4080): /* Creative Live Cam VF0610 */
	case USB_ID(0x04d8, 0xfeea): /* Benchmark DAC1 Pre */
	case USB_ID(0x0556, 0x0014): /* Phoenix Audio TMX320VC */
	case USB_ID(0x05a3, 0x9420): /* ELP HD USB Camera */
	case USB_ID(0x05a7, 0x1020): /* Bose Companion 5 */
	case USB_ID(0x074d, 0x3553): /* Outlaw RR2150 (Micronas UAC3553B) */
	case USB_ID(0x1395, 0x740a): /* Sennheiser DECT */
	case USB_ID(0x1901, 0x0191): /* GE B850V3 CP2114 audio interface */
	case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
	case USB_ID(0x2912, 0x30c8): /* Audioengine D1 */
		return true;
	}

	/* devices of these vendors don't support reading rate, either */
	switch (USB_ID_VENDOR(chip->usb_id)) {
	case 0x045e: /* MS Lifecam */
	case 0x047f: /* Plantronics */
	case 0x1de7: /* Phoenix Audio */
		return true;
	}

	return false;
}

/* ITF-USB DSD based DACs need a vendor cmd to switch
 * between PCM and native DSD mode
 */
static bool is_itf_usb_dsd_dac(unsigned int id)
{
	switch (id) {
	case USB_ID(0x154e, 0x1002): /* Denon DCD-1500RE */
	case USB_ID(0x154e, 0x1003): /* Denon DA-300USB */
	case USB_ID(0x154e, 0x3005): /* Marantz HD-DAC1 */
	case USB_ID(0x154e, 0x3006): /* Marantz SA-14S1 */
	case USB_ID(0x1852, 0x5065): /* Luxman DA-06 */
	case USB_ID(0x0644, 0x8043): /* TEAC UD-501/UD-501V2/UD-503/NT-503 */
	case USB_ID(0x0644, 0x8044): /* Esoteric D-05X */
	case USB_ID(0x0644, 0x804a): /* TEAC UD-301 */
		return true;
	}
	return false;
}

int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
			      struct audioformat *fmt)
{
	struct usb_device *dev = subs->dev;
	int err;

	if (is_itf_usb_dsd_dac(subs->stream->chip->usb_id)) {
		/* First switch to alt set 0, otherwise the mode switch cmd
		 * will not be accepted by the DAC
		 */
		err = usb_set_interface(dev, fmt->iface, 0);
		if (err < 0)
			return err;

		msleep(20); /* Delay needed after setting the interface */

		/* Vendor mode switch cmd is required. */
		if (fmt->formats & SNDRV_PCM_FMTBIT_DSD_U32_BE) {
			/* DSD mode (DSD_U32) requested */
			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
					      1, 1, NULL, 0);
			if (err < 0)
				return err;

		} else {
			/* PCM or DOP mode (S32) requested */
			/* PCM mode (S16) requested */
			err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
					      USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
					      0, 1, NULL, 0);
			if (err < 0)
				return err;

		}
		msleep(20);
	}
	return 0;
}

void snd_usb_endpoint_start_quirk(struct snd_usb_endpoint *ep)
{
	/*
	 * "Playback Design" products send bogus feedback data at the start
	 * of the stream. Ignore them.
	 */
	if (USB_ID_VENDOR(ep->chip->usb_id) == 0x23ba &&
	    ep->type == SND_USB_ENDPOINT_TYPE_SYNC)
		ep->skip_packets = 4;

	/*
	 * M-Audio Fast Track C400/C600 - when packets are not skipped, real
	 * world latency varies by approx. +/- 50 frames (at 96KHz) each time
	 * the stream is (re)started. When skipping packets 16 at endpoint
	 * start up, the real world latency is stable within +/- 1 frame (also
	 * across power cycles).
	 */
	if ((ep->chip->usb_id == USB_ID(0x0763, 0x2030) ||
	     ep->chip->usb_id == USB_ID(0x0763, 0x2031)) &&
	    ep->type == SND_USB_ENDPOINT_TYPE_DATA)
		ep->skip_packets = 16;

	/* Work around devices that report unreasonable feedback data */
	if ((ep->chip->usb_id == USB_ID(0x0644, 0x8038) ||  /* TEAC UD-H01 */
	     ep->chip->usb_id == USB_ID(0x1852, 0x5034)) && /* T+A Dac8 */
	    ep->syncmaxsize == 4)
		ep->tenor_fb_quirk = 1;
}

void snd_usb_set_interface_quirk(struct usb_device *dev)
{
	struct snd_usb_audio *chip = dev_get_drvdata(&dev->dev);

	if (!chip)
		return;
	/*
	 * "Playback Design" products need a 50ms delay after setting the
	 * USB interface.
	 */
	switch (USB_ID_VENDOR(chip->usb_id)) {
	case 0x23ba: /* Playback Design */
	case 0x0644: /* TEAC Corp. */
		msleep(50);
		break;
	}
}

/* quirk applied after snd_usb_ctl_msg(); not applied during boot quirks */
void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
			   __u8 request, __u8 requesttype, __u16 value,
			   __u16 index, void *data, __u16 size)
{
	struct snd_usb_audio *chip = dev_get_drvdata(&dev->dev);

	if (!chip)
		return;
	/*
	 * "Playback Design" products need a 20ms delay after each
	 * class compliant request
	 */
	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
		msleep(20);

	/*
	 * "TEAC Corp." products need a 20ms delay after each
	 * class compliant request
	 */
	if (USB_ID_VENDOR(chip->usb_id) == 0x0644 &&
	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
		msleep(20);

	/* ITF-USB DSD based DACs functionality need a delay
	 * after each class compliant request
	 */
	if (is_itf_usb_dsd_dac(chip->usb_id)
	    && (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
		msleep(20);

	/* Zoom R16/24, Logitech H650e, Jabra 550a, Kingston HyperX needs a tiny
	 * delay here, otherwise requests like get/set frequency return as
	 * failed despite actually succeeding.
	 */
	if ((chip->usb_id == USB_ID(0x1686, 0x00dd) ||
	     chip->usb_id == USB_ID(0x046d, 0x0a46) ||
	     chip->usb_id == USB_ID(0x0b0e, 0x0349) ||
	     chip->usb_id == USB_ID(0x0951, 0x16ad)) &&
	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
		usleep_range(1000, 2000);

	/*
	 * Samsung USBC Headset (AKG) need a tiny delay after each
	 * class compliant request. (Model number: AAM625R or AAM627R)
	 */
	if (chip->usb_id == USB_ID(0x04e8, 0xa051) &&
	    (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
		usleep_range(5000, 6000);
}

/*
 * snd_usb_interface_dsd_format_quirks() is called from format.c to
 * augment the PCM format bit-field for DSD types. The UAC standards
 * don't have a designated bit field to denote DSD-capable interfaces,
 * hence all hardware that is known to support this format has to be
 * listed here.
 */
u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
					struct audioformat *fp,
					unsigned int sample_bytes)
{
	struct usb_interface *iface;

	/* Playback Designs */
	if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
	    USB_ID_PRODUCT(chip->usb_id) < 0x0110) {
		switch (fp->altsetting) {
		case 1:
			fp->dsd_dop = true;
			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
		case 2:
			fp->dsd_bitrev = true;
			return SNDRV_PCM_FMTBIT_DSD_U8;
		case 3:
			fp->dsd_bitrev = true;
			return SNDRV_PCM_FMTBIT_DSD_U16_LE;
		}
	}

	/* XMOS based USB DACs */
	switch (chip->usb_id) {
	case USB_ID(0x1511, 0x0037): /* AURALiC VEGA */
	case USB_ID(0x2522, 0x0012): /* LH Labs VI DAC Infinity */
	case USB_ID(0x2772, 0x0230): /* Pro-Ject Pre Box S2 Digital */
		if (fp->altsetting == 2)
			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
		break;

	case USB_ID(0x0d8c, 0x0316): /* Hegel HD12 DSD */
	case USB_ID(0x10cb, 0x0103): /* The Bit Opus #3; with fp->dsd_raw */
	case USB_ID(0x16d0, 0x06b2): /* NuPrime DAC-10 */
	case USB_ID(0x16d0, 0x09dd): /* Encore mDSD */
	case USB_ID(0x16d0, 0x0733): /* Furutech ADL Stratos */
	case USB_ID(0x16d0, 0x09db): /* NuPrime Audio DAC-9 */
	case USB_ID(0x1db5, 0x0003): /* Bryston BDA3 */
	case USB_ID(0x22e1, 0xca01): /* HDTA Serenade DSD */
	case USB_ID(0x249c, 0x9326): /* M2Tech Young MkIII */
	case USB_ID(0x2616, 0x0106): /* PS Audio NuWave DAC */
	case USB_ID(0x2622, 0x0041): /* Audiolab M-DAC+ */
	case USB_ID(0x27f7, 0x3002): /* W4S DAC-2v2SE */
	case USB_ID(0x29a2, 0x0086): /* Mutec MC3+ USB */
	case USB_ID(0x6b42, 0x0042): /* MSB Technology */
		if (fp->altsetting == 3)
			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
		break;

	/* Amanero Combo384 USB based DACs with native DSD support */
	case USB_ID(0x16d0, 0x071a):  /* Amanero - Combo384 */
	case USB_ID(0x2ab6, 0x0004):  /* T+A DAC8DSD-V2.0, MP1000E-V2.0, MP2000R-V2.0, MP2500R-V2.0, MP3100HV-V2.0 */
	case USB_ID(0x2ab6, 0x0005):  /* T+A USB HD Audio 1 */
	case USB_ID(0x2ab6, 0x0006):  /* T+A USB HD Audio 2 */
		if (fp->altsetting == 2) {
			switch (le16_to_cpu(chip->dev->descriptor.bcdDevice)) {
			case 0x199:
				return SNDRV_PCM_FMTBIT_DSD_U32_LE;
			case 0x19b:
			case 0x203:
				return SNDRV_PCM_FMTBIT_DSD_U32_BE;
			default:
				break;
			}
		}
		break;
	case USB_ID(0x16d0, 0x0a23):
		if (fp->altsetting == 2)
			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
		break;

	default:
		break;
	}

	/* ITF-USB DSD based DACs */
	if (is_itf_usb_dsd_dac(chip->usb_id)) {
		iface = usb_ifnum_to_if(chip->dev, fp->iface);

		/* Altsetting 2 support native DSD if the num of altsets is
		 * three (0-2),
		 * Altsetting 3 support native DSD if the num of altsets is
		 * four (0-3).
		 */
		if (fp->altsetting == iface->num_altsetting - 1)
			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
	}

	/* Mostly generic method to detect many DSD-capable implementations -
	 * from XMOS/Thesycon
	 */
	switch (USB_ID_VENDOR(chip->usb_id)) {
	case 0x152a:  /* Thesycon devices */
	case 0x20b1:  /* XMOS based devices */
	case 0x22d9:  /* Oppo */
	case 0x23ba:  /* Playback Designs */
	case 0x25ce:  /* Mytek devices */
	case 0x278b:  /* Rotel? */
	case 0x292b:  /* Gustard/Ess based devices */
	case 0x2ab6:  /* T+A devices */
	case 0x3842:  /* EVGA */
	case 0xc502:  /* HiBy devices */
		if (fp->dsd_raw)
			return SNDRV_PCM_FMTBIT_DSD_U32_BE;
		break;
	default:
		break;

	}

	return 0;
}

void snd_usb_audioformat_attributes_quirk(struct snd_usb_audio *chip,
					  struct audioformat *fp,
					  int stream)
{
	switch (chip->usb_id) {
	case USB_ID(0x0a92, 0x0053): /* AudioTrak Optoplay */
		/* Optoplay sets the sample rate attribute although
		 * it seems not supporting it in fact.
		 */
		fp->attributes &= ~UAC_EP_CS_ATTR_SAMPLE_RATE;
		break;
	case USB_ID(0x041e, 0x3020): /* Creative SB Audigy 2 NX */
	case USB_ID(0x0763, 0x2003): /* M-Audio Audiophile USB */
		/* doesn't set the sample rate attribute, but supports it */
		fp->attributes |= UAC_EP_CS_ATTR_SAMPLE_RATE;
		break;
	case USB_ID(0x0763, 0x2001):  /* M-Audio Quattro USB */
	case USB_ID(0x0763, 0x2012):  /* M-Audio Fast Track Pro USB */
	case USB_ID(0x047f, 0x0ca1): /* plantronics headset */
	case USB_ID(0x077d, 0x07af): /* Griffin iMic (note that there is
					an older model 77d:223) */
	/*
	 * plantronics headset and Griffin iMic have set adaptive-in
	 * although it's really not...
	 */
		fp->ep_attr &= ~USB_ENDPOINT_SYNCTYPE;
		if (stream == SNDRV_PCM_STREAM_PLAYBACK)
			fp->ep_attr |= USB_ENDPOINT_SYNC_ADAPTIVE;
		else
			fp->ep_attr |= USB_ENDPOINT_SYNC_SYNC;
		break;
	case USB_ID(0x07fd, 0x0004):  /* MOTU MicroBook IIc */
		/*
		 * MaxPacketsOnly attribute is erroneously set in endpoint
		 * descriptors. As a result this card produces noise with
		 * all sample rates other than 96 KHz.
		 */
		fp->attributes &= ~UAC_EP_CS_ATTR_FILL_MAX;
		break;
	}
}

/*
 * registration quirk:
 * the registration is skipped if a device matches with the given ID,
 * unless the interface reaches to the defined one.  This is for delaying
 * the registration until the last known interface, so that the card and
 * devices appear at the same time.
 */

struct registration_quirk {
	unsigned int usb_id;	/* composed via USB_ID() */
	unsigned int interface;	/* the interface to trigger register */
};

#define REG_QUIRK_ENTRY(vendor, product, iface) \
	{ .usb_id = USB_ID(vendor, product), .interface = (iface) }

static const struct registration_quirk registration_quirks[] = {
	REG_QUIRK_ENTRY(0x0951, 0x16d8, 2),	/* Kingston HyperX AMP */
	REG_QUIRK_ENTRY(0x0951, 0x16ed, 2),	/* Kingston HyperX Cloud Alpha S */
	REG_QUIRK_ENTRY(0x0951, 0x16ea, 2),	/* Kingston HyperX Cloud Flight S */
	{ 0 }					/* terminator */
};

/* return true if skipping registration */
bool snd_usb_registration_quirk(struct snd_usb_audio *chip, int iface)
{
	const struct registration_quirk *q;

	for (q = registration_quirks; q->usb_id; q++)
		if (chip->usb_id == q->usb_id)
			return iface != q->interface;

	/* Register as normal */
	return false;
}