summaryrefslogtreecommitdiffstats
path: root/src/modules/alsa/alsa-sink.c
blob: 9116a69fc20662a179cae93bafd7f37771aeeddd (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
/***
  This file is part of PulseAudio.

  Copyright 2004-2008 Lennart Poettering
  Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB

  PulseAudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2.1 of the License,
  or (at your option) any later version.

  PulseAudio 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.

  You should have received a copy of the GNU Lesser General Public License
  along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>

#include <asoundlib.h>

#ifdef HAVE_VALGRIND_MEMCHECK_H
#include <valgrind/memcheck.h>
#endif

#include <pulse/i18n.h>
#include <pulse/rtclock.h>
#include <pulse/timeval.h>
#include <pulse/util.h>
#include <pulse/xmalloc.h>

#include <pulsecore/core.h>
#include <pulsecore/module.h>
#include <pulsecore/memchunk.h>
#include <pulsecore/sink.h>
#include <pulsecore/modargs.h>
#include <pulsecore/core-rtclock.h>
#include <pulsecore/core-util.h>
#include <pulsecore/sample-util.h>
#include <pulsecore/log.h>
#include <pulsecore/macro.h>
#include <pulsecore/thread.h>
#include <pulsecore/core-error.h>
#include <pulsecore/thread-mq.h>
#include <pulsecore/rtpoll.h>
#include <pulsecore/time-smoother.h>

#include <modules/reserve-wrap.h>

#include "alsa-util.h"
#include "alsa-sink.h"

/* #define DEBUG_TIMING */

#define DEFAULT_DEVICE "default"
#define DEFAULT_TSCHED_BUFFER_USEC (2*PA_USEC_PER_SEC)            /* 2s   -- Overall buffer size */
#define DEFAULT_TSCHED_WATERMARK_USEC (20*PA_USEC_PER_MSEC)       /* 20ms -- Fill up when only this much is left in the buffer */
#define TSCHED_WATERMARK_STEP_USEC (10*PA_USEC_PER_MSEC)          /* 10ms -- On underrun, increase watermark by this */
#define TSCHED_MIN_SLEEP_USEC (10*PA_USEC_PER_MSEC)               /* 10ms -- Sleep at least 10ms on each iteration */
#define TSCHED_MIN_WAKEUP_USEC (4*PA_USEC_PER_MSEC)               /* 4ms  -- Wakeup at least this long before the buffer runs empty*/

struct userdata {
    pa_core *core;
    pa_module *module;
    pa_sink *sink;

    pa_thread *thread;
    pa_thread_mq thread_mq;
    pa_rtpoll *rtpoll;

    snd_pcm_t *pcm_handle;

    pa_alsa_fdlist *mixer_fdl;
    snd_mixer_t *mixer_handle;
    pa_alsa_path_set *mixer_path_set;
    pa_alsa_path *mixer_path;

    pa_cvolume hardware_volume;

    size_t
        frame_size,
        fragment_size,
        hwbuf_size,
        tsched_watermark,
        hwbuf_unused,
        min_sleep,
        min_wakeup,
        watermark_step;

    unsigned nfragments;
    pa_memchunk memchunk;

    char *device_name;  /* name of the PCM device */
    char *control_device; /* name of the control device */

    pa_bool_t use_mmap:1, use_tsched:1;

    pa_bool_t first, after_rewind;

    pa_rtpoll_item *alsa_rtpoll_item;

    snd_mixer_selem_channel_id_t mixer_map[SND_MIXER_SCHN_LAST];

    pa_smoother *smoother;
    uint64_t write_count;
    uint64_t since_start;

    pa_reserve_wrapper *reserve;
    pa_hook_slot *reserve_slot;
    pa_reserve_monitor_wrapper *monitor;
    pa_hook_slot *monitor_slot;
};

static void userdata_free(struct userdata *u);

static pa_hook_result_t reserve_cb(pa_reserve_wrapper *r, void *forced, struct userdata *u) {
    pa_assert(r);
    pa_assert(u);

    if (pa_sink_suspend(u->sink, TRUE, PA_SUSPEND_APPLICATION) < 0)
        return PA_HOOK_CANCEL;

    return PA_HOOK_OK;
}

static void reserve_done(struct userdata *u) {
    pa_assert(u);

    if (u->reserve_slot) {
        pa_hook_slot_free(u->reserve_slot);
        u->reserve_slot = NULL;
    }

    if (u->reserve) {
        pa_reserve_wrapper_unref(u->reserve);
        u->reserve = NULL;
    }
}

static void reserve_update(struct userdata *u) {
    const char *description;
    pa_assert(u);

    if (!u->sink || !u->reserve)
        return;

    if ((description = pa_proplist_gets(u->sink->proplist, PA_PROP_DEVICE_DESCRIPTION)))
        pa_reserve_wrapper_set_application_device_name(u->reserve, description);
}

static int reserve_init(struct userdata *u, const char *dname) {
    char *rname;

    pa_assert(u);
    pa_assert(dname);

    if (u->reserve)
        return 0;

    if (pa_in_system_mode())
        return 0;

    /* We are resuming, try to lock the device */
    if (!(rname = pa_alsa_get_reserve_name(dname)))
        return 0;

    u->reserve = pa_reserve_wrapper_get(u->core, rname);
    pa_xfree(rname);

    if (!(u->reserve))
        return -1;

    reserve_update(u);

    pa_assert(!u->reserve_slot);
    u->reserve_slot = pa_hook_connect(pa_reserve_wrapper_hook(u->reserve), PA_HOOK_NORMAL, (pa_hook_cb_t) reserve_cb, u);

    return 0;
}

static pa_hook_result_t monitor_cb(pa_reserve_monitor_wrapper *w, void* busy, struct userdata *u) {
    pa_bool_t b;

    pa_assert(w);
    pa_assert(u);

    b = PA_PTR_TO_UINT(busy) && !u->reserve;

    pa_sink_suspend(u->sink, b, PA_SUSPEND_APPLICATION);
    return PA_HOOK_OK;
}

static void monitor_done(struct userdata *u) {
    pa_assert(u);

    if (u->monitor_slot) {
        pa_hook_slot_free(u->monitor_slot);
        u->monitor_slot = NULL;
    }

    if (u->monitor) {
        pa_reserve_monitor_wrapper_unref(u->monitor);
        u->monitor = NULL;
    }
}

static int reserve_monitor_init(struct userdata *u, const char *dname) {
    char *rname;

    pa_assert(u);
    pa_assert(dname);

    if (pa_in_system_mode())
        return 0;

    /* We are resuming, try to lock the device */
    if (!(rname = pa_alsa_get_reserve_name(dname)))
        return 0;

    u->monitor = pa_reserve_monitor_wrapper_get(u->core, rname);
    pa_xfree(rname);

    if (!(u->monitor))
        return -1;

    pa_assert(!u->monitor_slot);
    u->monitor_slot = pa_hook_connect(pa_reserve_monitor_wrapper_hook(u->monitor), PA_HOOK_NORMAL, (pa_hook_cb_t) monitor_cb, u);

    return 0;
}

static void fix_min_sleep_wakeup(struct userdata *u) {
    size_t max_use, max_use_2;

    pa_assert(u);

    max_use = u->hwbuf_size - u->hwbuf_unused;
    max_use_2 = pa_frame_align(max_use/2, &u->sink->sample_spec);

    u->min_sleep = pa_usec_to_bytes(TSCHED_MIN_SLEEP_USEC, &u->sink->sample_spec);
    u->min_sleep = PA_CLAMP(u->min_sleep, u->frame_size, max_use_2);

    u->min_wakeup = pa_usec_to_bytes(TSCHED_MIN_WAKEUP_USEC, &u->sink->sample_spec);
    u->min_wakeup = PA_CLAMP(u->min_wakeup, u->frame_size, max_use_2);
}

static void fix_tsched_watermark(struct userdata *u) {
    size_t max_use;
    pa_assert(u);

    max_use = u->hwbuf_size - u->hwbuf_unused;

    if (u->tsched_watermark > max_use - u->min_sleep)
        u->tsched_watermark = max_use - u->min_sleep;

    if (u->tsched_watermark < u->min_wakeup)
        u->tsched_watermark = u->min_wakeup;
}

static void adjust_after_underrun(struct userdata *u) {
    size_t old_watermark;
    pa_usec_t old_min_latency, new_min_latency;

    pa_assert(u);
    pa_assert(u->use_tsched);

    /* First, just try to increase the watermark */
    old_watermark = u->tsched_watermark;
    u->tsched_watermark = PA_MIN(u->tsched_watermark * 2, u->tsched_watermark + u->watermark_step);
    fix_tsched_watermark(u);

    if (old_watermark != u->tsched_watermark) {
        pa_log_notice("Increasing wakeup watermark to %0.2f ms",
                      (double) pa_bytes_to_usec(u->tsched_watermark, &u->sink->sample_spec) / PA_USEC_PER_MSEC);
        return;
    }

    /* Hmm, we cannot increase the watermark any further, hence let's raise the latency */
    old_min_latency = u->sink->thread_info.min_latency;
    new_min_latency = PA_MIN(old_min_latency * 2, old_min_latency + TSCHED_WATERMARK_STEP_USEC);
    new_min_latency = PA_MIN(new_min_latency, u->sink->thread_info.max_latency);

    if (old_min_latency != new_min_latency) {
        pa_log_notice("Increasing minimal latency to %0.2f ms",
                      (double) new_min_latency / PA_USEC_PER_MSEC);

        pa_sink_set_latency_range_within_thread(u->sink, new_min_latency, u->sink->thread_info.max_latency);
        return;
    }

    /* When we reach this we're officialy fucked! */
}

static void hw_sleep_time(struct userdata *u, pa_usec_t *sleep_usec, pa_usec_t*process_usec) {
    pa_usec_t usec, wm;

    pa_assert(sleep_usec);
    pa_assert(process_usec);

    pa_assert(u);

    usec = pa_sink_get_requested_latency_within_thread(u->sink);

    if (usec == (pa_usec_t) -1)
        usec = pa_bytes_to_usec(u->hwbuf_size, &u->sink->sample_spec);

    wm = pa_bytes_to_usec(u->tsched_watermark, &u->sink->sample_spec);

    if (wm > usec)
        wm = usec/2;

    *sleep_usec = usec - wm;
    *process_usec = wm;

#ifdef DEBUG_TIMING
    pa_log_debug("Buffer time: %lu ms; Sleep time: %lu ms; Process time: %lu ms",
                 (unsigned long) (usec / PA_USEC_PER_MSEC),
                 (unsigned long) (*sleep_usec / PA_USEC_PER_MSEC),
                 (unsigned long) (*process_usec / PA_USEC_PER_MSEC));
#endif
}

static int try_recover(struct userdata *u, const char *call, int err) {
    pa_assert(u);
    pa_assert(call);
    pa_assert(err < 0);

    pa_log_debug("%s: %s", call, pa_alsa_strerror(err));

    pa_assert(err != -EAGAIN);

    if (err == -EPIPE)
        pa_log_debug("%s: Buffer underrun!", call);

    if ((err = snd_pcm_recover(u->pcm_handle, err, 1)) < 0) {
        pa_log("%s: %s", call, pa_alsa_strerror(err));
        return -1;
    }

    u->first = TRUE;
    u->since_start = 0;
    return 0;
}

static size_t check_left_to_play(struct userdata *u, size_t n_bytes) {
    size_t left_to_play;

    /* We use <= instead of < for this check here because an underrun
     * only happens after the last sample was processed, not already when
     * it is removed from the buffer. This is particularly important
     * when block transfer is used. */

    if (n_bytes <= u->hwbuf_size) {
        left_to_play = u->hwbuf_size - n_bytes;

#ifdef DEBUG_TIMING
        pa_log_debug("%0.2f ms left to play", (double) pa_bytes_to_usec(left_to_play, &u->sink->sample_spec) / PA_USEC_PER_MSEC);
#endif

    } else {
        left_to_play = 0;

#ifdef DEBUG_TIMING
        PA_DEBUG_TRAP;
#endif

        if (!u->first && !u->after_rewind) {

            if (pa_log_ratelimit())
                pa_log_info("Underrun!");

            if (u->use_tsched)
                adjust_after_underrun(u);
        }
    }

    return left_to_play;
}

static int mmap_write(struct userdata *u, pa_usec_t *sleep_usec, pa_bool_t polled) {
    pa_bool_t work_done = TRUE;
    pa_usec_t max_sleep_usec = 0, process_usec = 0;
    size_t left_to_play;
    unsigned j = 0;

    pa_assert(u);
    pa_sink_assert_ref(u->sink);

    if (u->use_tsched)
        hw_sleep_time(u, &max_sleep_usec, &process_usec);

    for (;;) {
        snd_pcm_sframes_t n;
        size_t n_bytes;
        int r;

        /* First we determine how many samples are missing to fill the
         * buffer up to 100% */

        if (PA_UNLIKELY((n = pa_alsa_safe_avail(u->pcm_handle, u->hwbuf_size, &u->sink->sample_spec)) < 0)) {

            if ((r = try_recover(u, "snd_pcm_avail", (int) n)) == 0)
                continue;

            return r;
        }

        n_bytes = (size_t) n * u->frame_size;

#ifdef DEBUG_TIMING
        pa_log_debug("avail: %lu", (unsigned long) n_bytes);
#endif

        left_to_play = check_left_to_play(u, n_bytes);

        if (u->use_tsched)

            /* We won't fill up the playback buffer before at least
            * half the sleep time is over because otherwise we might
            * ask for more data from the clients then they expect. We
            * need to guarantee that clients only have to keep around
            * a single hw buffer length. */

            if (!polled &&
                pa_bytes_to_usec(left_to_play, &u->sink->sample_spec) > process_usec+max_sleep_usec/2) {
#ifdef DEBUG_TIMING
                pa_log_debug("Not filling up, because too early.");
#endif
                break;
            }

        if (PA_UNLIKELY(n_bytes <= u->hwbuf_unused)) {

            if (polled)
                PA_ONCE_BEGIN {
                    char *dn = pa_alsa_get_driver_name_by_pcm(u->pcm_handle);
                    pa_log(_("ALSA woke us up to write new data to the device, but there was actually nothing to write!\n"
                             "Most likely this is a bug in the ALSA driver '%s'. Please report this issue to the ALSA developers.\n"
                             "We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail."),
                           pa_strnull(dn));
                    pa_xfree(dn);
                } PA_ONCE_END;

#ifdef DEBUG_TIMING
            pa_log_debug("Not filling up, because not necessary.");
#endif
            break;
        }


        if (++j > 10) {
#ifdef DEBUG_TIMING
            pa_log_debug("Not filling up, because already too many iterations.");
#endif

            break;
        }

        n_bytes -= u->hwbuf_unused;
        polled = FALSE;

#ifdef DEBUG_TIMING
        pa_log_debug("Filling up");
#endif

        for (;;) {
            pa_memchunk chunk;
            void *p;
            int err;
            const snd_pcm_channel_area_t *areas;
            snd_pcm_uframes_t offset, frames;
            snd_pcm_sframes_t sframes;

            frames = (snd_pcm_uframes_t) (n_bytes / u->frame_size);
/*             pa_log_debug("%lu frames to write", (unsigned long) frames); */

            if (PA_UNLIKELY((err = pa_alsa_safe_mmap_begin(u->pcm_handle, &areas, &offset, &frames, u->hwbuf_size, &u->sink->sample_spec)) < 0)) {

                if ((r = try_recover(u, "snd_pcm_mmap_begin", err)) == 0)
                    continue;

                return r;
            }

            /* Make sure that if these memblocks need to be copied they will fit into one slot */
            if (frames > pa_mempool_block_size_max(u->sink->core->mempool)/u->frame_size)
                frames = pa_mempool_block_size_max(u->sink->core->mempool)/u->frame_size;

            /* Check these are multiples of 8 bit */
            pa_assert((areas[0].first & 7) == 0);
            pa_assert((areas[0].step & 7)== 0);

            /* We assume a single interleaved memory buffer */
            pa_assert((areas[0].first >> 3) == 0);
            pa_assert((areas[0].step >> 3) == u->frame_size);

            p = (uint8_t*) areas[0].addr + (offset * u->frame_size);

            chunk.memblock = pa_memblock_new_fixed(u->core->mempool, p, frames * u->frame_size, TRUE);
            chunk.length = pa_memblock_get_length(chunk.memblock);
            chunk.index = 0;

            pa_sink_render_into_full(u->sink, &chunk);
            pa_memblock_unref_fixed(chunk.memblock);

            if (PA_UNLIKELY((sframes = snd_pcm_mmap_commit(u->pcm_handle, offset, frames)) < 0)) {

                if ((r = try_recover(u, "snd_pcm_mmap_commit", (int) sframes)) == 0)
                    continue;

                return r;
            }

            work_done = TRUE;

            u->write_count += frames * u->frame_size;
            u->since_start += frames * u->frame_size;

#ifdef DEBUG_TIMING
            pa_log_debug("Wrote %lu bytes (of possible %lu bytes)", (unsigned long) (frames * u->frame_size), (unsigned long) n_bytes);
#endif

            if ((size_t) frames * u->frame_size >= n_bytes)
                break;

            n_bytes -= (size_t) frames * u->frame_size;
        }
    }

    *sleep_usec = pa_bytes_to_usec(left_to_play, &u->sink->sample_spec);

    if (*sleep_usec > process_usec)
        *sleep_usec -= process_usec;
    else
        *sleep_usec = 0;

    return work_done ? 1 : 0;
}

static int unix_write(struct userdata *u, pa_usec_t *sleep_usec, pa_bool_t polled) {
    pa_bool_t work_done = FALSE;
    pa_usec_t max_sleep_usec = 0, process_usec = 0;
    size_t left_to_play;
    unsigned j = 0;

    pa_assert(u);
    pa_sink_assert_ref(u->sink);

    if (u->use_tsched)
        hw_sleep_time(u, &max_sleep_usec, &process_usec);

    for (;;) {
        snd_pcm_sframes_t n;
        size_t n_bytes;
        int r;

        if (PA_UNLIKELY((n = pa_alsa_safe_avail(u->pcm_handle, u->hwbuf_size, &u->sink->sample_spec)) < 0)) {

            if ((r = try_recover(u, "snd_pcm_avail", (int) n)) == 0)
                continue;

            return r;
        }

        n_bytes = (size_t) n * u->frame_size;
        left_to_play = check_left_to_play(u, n_bytes);

        if (u->use_tsched)

            /* We won't fill up the playback buffer before at least
            * half the sleep time is over because otherwise we might
            * ask for more data from the clients then they expect. We
            * need to guarantee that clients only have to keep around
            * a single hw buffer length. */

            if (!polled &&
                pa_bytes_to_usec(left_to_play, &u->sink->sample_spec) > process_usec+max_sleep_usec/2)
                break;

        if (PA_UNLIKELY(n_bytes <= u->hwbuf_unused)) {

            if (polled)
                PA_ONCE_BEGIN {
                    char *dn = pa_alsa_get_driver_name_by_pcm(u->pcm_handle);
                    pa_log(_("ALSA woke us up to write new data to the device, but there was actually nothing to write!\n"
                             "Most likely this is a bug in the ALSA driver '%s'. Please report this issue to the ALSA developers.\n"
                             "We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail."),
                           pa_strnull(dn));
                    pa_xfree(dn);
                } PA_ONCE_END;

            break;
        }

        if (++j > 10) {
#ifdef DEBUG_TIMING
            pa_log_debug("Not filling up, because already too many iterations.");
#endif

            break;
        }

        n_bytes -= u->hwbuf_unused;
        polled = FALSE;

        for (;;) {
            snd_pcm_sframes_t frames;
            void *p;

/*         pa_log_debug("%lu frames to write", (unsigned long) frames); */

            if (u->memchunk.length <= 0)
                pa_sink_render(u->sink, n_bytes, &u->memchunk);

            pa_assert(u->memchunk.length > 0);

            frames = (snd_pcm_sframes_t) (u->memchunk.length / u->frame_size);

            if (frames > (snd_pcm_sframes_t) (n_bytes/u->frame_size))
                frames = (snd_pcm_sframes_t) (n_bytes/u->frame_size);

            p = pa_memblock_acquire(u->memchunk.memblock);
            frames = snd_pcm_writei(u->pcm_handle, (const uint8_t*) p + u->memchunk.index, (snd_pcm_uframes_t) frames);
            pa_memblock_release(u->memchunk.memblock);

            pa_assert(frames != 0);

            if (PA_UNLIKELY(frames < 0)) {

                if ((r = try_recover(u, "snd_pcm_writei", (int) frames)) == 0)
                    continue;

                return r;
            }

            u->memchunk.index += (size_t) frames * u->frame_size;
            u->memchunk.length -= (size_t) frames * u->frame_size;

            if (u->memchunk.length <= 0) {
                pa_memblock_unref(u->memchunk.memblock);
                pa_memchunk_reset(&u->memchunk);
            }

            work_done = TRUE;

            u->write_count += frames * u->frame_size;
            u->since_start += frames * u->frame_size;

/*         pa_log_debug("wrote %lu frames", (unsigned long) frames); */

            if ((size_t) frames * u->frame_size >= n_bytes)
                break;

            n_bytes -= (size_t) frames * u->frame_size;
        }
    }

    *sleep_usec = pa_bytes_to_usec(left_to_play, &u->sink->sample_spec);

    if (*sleep_usec > process_usec)
        *sleep_usec -= process_usec;
    else
        *sleep_usec = 0;

    return work_done ? 1 : 0;
}

static void update_smoother(struct userdata *u) {
    snd_pcm_sframes_t delay = 0;
    int64_t position;
    int err;
    pa_usec_t now1 = 0, now2;
    snd_pcm_status_t *status;

    snd_pcm_status_alloca(&status);

    pa_assert(u);
    pa_assert(u->pcm_handle);

    /* Let's update the time smoother */

    if (PA_UNLIKELY((err = pa_alsa_safe_delay(u->pcm_handle, &delay, u->hwbuf_size, &u->sink->sample_spec)) < 0)) {
        pa_log_warn("Failed to query DSP status data: %s", pa_alsa_strerror(err));
        return;
    }

    if (PA_UNLIKELY((err = snd_pcm_status(u->pcm_handle, status)) < 0))
        pa_log_warn("Failed to get timestamp: %s", pa_alsa_strerror(err));
    else {
        snd_htimestamp_t htstamp = { 0, 0 };
        snd_pcm_status_get_htstamp(status, &htstamp);
        now1 = pa_timespec_load(&htstamp);
    }

    position = (int64_t) u->write_count - ((int64_t) delay * (int64_t) u->frame_size);

    if (PA_UNLIKELY(position < 0))
        position = 0;

    /* Hmm, if the timestamp is 0, then it wasn't set and we take the current time */
    if (now1 <= 0)
        now1 = pa_rtclock_now();

    now2 = pa_bytes_to_usec((uint64_t) position, &u->sink->sample_spec);

    pa_smoother_put(u->smoother, now1, now2);
}

static pa_usec_t sink_get_latency(struct userdata *u) {
    pa_usec_t r;
    int64_t delay;
    pa_usec_t now1, now2;

    pa_assert(u);

    now1 = pa_rtclock_now();
    now2 = pa_smoother_get(u->smoother, now1);

    delay = (int64_t) pa_bytes_to_usec(u->write_count, &u->sink->sample_spec) - (int64_t) now2;

    r = delay >= 0 ? (pa_usec_t) delay : 0;

    if (u->memchunk.memblock)
        r += pa_bytes_to_usec(u->memchunk.length, &u->sink->sample_spec);

    return r;
}

static int build_pollfd(struct userdata *u) {
    pa_assert(u);
    pa_assert(u->pcm_handle);

    if (u->alsa_rtpoll_item)
        pa_rtpoll_item_free(u->alsa_rtpoll_item);

    if (!(u->alsa_rtpoll_item = pa_alsa_build_pollfd(u->pcm_handle, u->rtpoll)))
        return -1;

    return 0;
}

/* Called from IO context */
static int suspend(struct userdata *u) {
    pa_assert(u);
    pa_assert(u->pcm_handle);

    pa_smoother_pause(u->smoother, pa_rtclock_now());

    /* Let's suspend -- we don't call snd_pcm_drain() here since that might
     * take awfully long with our long buffer sizes today. */
    snd_pcm_close(u->pcm_handle);
    u->pcm_handle = NULL;

    if (u->alsa_rtpoll_item) {
        pa_rtpoll_item_free(u->alsa_rtpoll_item);
        u->alsa_rtpoll_item = NULL;
    }

    pa_log_info("Device suspended...");

    return 0;
}

/* Called from IO context */
static int update_sw_params(struct userdata *u) {
    snd_pcm_uframes_t avail_min;
    int err;

    pa_assert(u);

    /* Use the full buffer if noone asked us for anything specific */
    u->hwbuf_unused = 0;

    if (u->use_tsched) {
        pa_usec_t latency;

        if ((latency = pa_sink_get_requested_latency_within_thread(u->sink)) != (pa_usec_t) -1) {
            size_t b;

            pa_log_debug("Latency set to %0.2fms", (double) latency / PA_USEC_PER_MSEC);

            b = pa_usec_to_bytes(latency, &u->sink->sample_spec);

            /* We need at least one sample in our buffer */

            if (PA_UNLIKELY(b < u->frame_size))
                b = u->frame_size;

            u->hwbuf_unused = PA_LIKELY(b < u->hwbuf_size) ? (u->hwbuf_size - b) : 0;
        }

        fix_min_sleep_wakeup(u);
        fix_tsched_watermark(u);
    }

    pa_log_debug("hwbuf_unused=%lu", (unsigned long) u->hwbuf_unused);

    /* We need at last one frame in the used part of the buffer */
    avail_min = (snd_pcm_uframes_t) u->hwbuf_unused / u->frame_size + 1;

    if (u->use_tsched) {
        pa_usec_t sleep_usec, process_usec;

        hw_sleep_time(u, &sleep_usec, &process_usec);
        avail_min += pa_usec_to_bytes(sleep_usec, &u->sink->sample_spec) / u->frame_size;
    }

    pa_log_debug("setting avail_min=%lu", (unsigned long) avail_min);

    if ((err = pa_alsa_set_sw_params(u->pcm_handle, avail_min)) < 0) {
        pa_log("Failed to set software parameters: %s", pa_alsa_strerror(err));
        return err;
    }

    pa_sink_set_max_request_within_thread(u->sink, u->hwbuf_size - u->hwbuf_unused);

    return 0;
}

/* Called from IO context */
static int unsuspend(struct userdata *u) {
    pa_sample_spec ss;
    int err;
    pa_bool_t b, d;
    unsigned nfrags;
    snd_pcm_uframes_t period_size;

    pa_assert(u);
    pa_assert(!u->pcm_handle);

    pa_log_info("Trying resume...");

    if ((err = snd_pcm_open(&u->pcm_handle, u->device_name, SND_PCM_STREAM_PLAYBACK,
                            /*SND_PCM_NONBLOCK|*/
                            SND_PCM_NO_AUTO_RESAMPLE|
                            SND_PCM_NO_AUTO_CHANNELS|
                            SND_PCM_NO_AUTO_FORMAT)) < 0) {
        pa_log("Error opening PCM device %s: %s", u->device_name, pa_alsa_strerror(err));
        goto fail;
    }

    ss = u->sink->sample_spec;
    nfrags = u->nfragments;
    period_size = u->fragment_size / u->frame_size;
    b = u->use_mmap;
    d = u->use_tsched;

    if ((err = pa_alsa_set_hw_params(u->pcm_handle, &ss, &nfrags, &period_size, u->hwbuf_size / u->frame_size, &b, &d, TRUE)) < 0) {
        pa_log("Failed to set hardware parameters: %s", pa_alsa_strerror(err));
        goto fail;
    }

    if (b != u->use_mmap || d != u->use_tsched) {
        pa_log_warn("Resume failed, couldn't get original access mode.");
        goto fail;
    }

    if (!pa_sample_spec_equal(&ss, &u->sink->sample_spec)) {
        pa_log_warn("Resume failed, couldn't restore original sample settings.");
        goto fail;
    }

    if (nfrags != u->nfragments || period_size*u->frame_size != u->fragment_size) {
        pa_log_warn("Resume failed, couldn't restore original fragment settings. (Old: %lu*%lu, New %lu*%lu)",
                    (unsigned long) u->nfragments, (unsigned long) u->fragment_size,
                    (unsigned long) nfrags, period_size * u->frame_size);
        goto fail;
    }

    if (update_sw_params(u) < 0)
        goto fail;

    if (build_pollfd(u) < 0)
        goto fail;

    u->first = TRUE;
    u->since_start = 0;

    pa_log_info("Resumed successfully...");

    return 0;

fail:
    if (u->pcm_handle) {
        snd_pcm_close(u->pcm_handle);
        u->pcm_handle = NULL;
    }

    return -1;
}

/* Called from IO context */
static int sink_process_msg(pa_msgobject *o, int code, void *data, int64_t offset, pa_memchunk *chunk) {
    struct userdata *u = PA_SINK(o)->userdata;

    switch (code) {

        case PA_SINK_MESSAGE_GET_LATENCY: {
            pa_usec_t r = 0;

            if (u->pcm_handle)
                r = sink_get_latency(u);

            *((pa_usec_t*) data) = r;

            return 0;
        }

        case PA_SINK_MESSAGE_SET_STATE:

            switch ((pa_sink_state_t) PA_PTR_TO_UINT(data)) {

                case PA_SINK_SUSPENDED:
                    pa_assert(PA_SINK_IS_OPENED(u->sink->thread_info.state));

                    if (suspend(u) < 0)
                        return -1;

                    break;

                case PA_SINK_IDLE:
                case PA_SINK_RUNNING:

                    if (u->sink->thread_info.state == PA_SINK_INIT) {
                        if (build_pollfd(u) < 0)
                            return -1;
                    }

                    if (u->sink->thread_info.state == PA_SINK_SUSPENDED) {
                        if (unsuspend(u) < 0)
                            return -1;
                    }

                    break;

                case PA_SINK_UNLINKED:
                case PA_SINK_INIT:
                case PA_SINK_INVALID_STATE:
                    ;
            }

            break;
    }

    return pa_sink_process_msg(o, code, data, offset, chunk);
}

/* Called from main context */
static int sink_set_state_cb(pa_sink *s, pa_sink_state_t new_state) {
    pa_sink_state_t old_state;
    struct userdata *u;

    pa_sink_assert_ref(s);
    pa_assert_se(u = s->userdata);

    old_state = pa_sink_get_state(u->sink);

    if (PA_SINK_IS_OPENED(old_state) && new_state == PA_SINK_SUSPENDED)
        reserve_done(u);
    else if (old_state == PA_SINK_SUSPENDED && PA_SINK_IS_OPENED(new_state))
        if (reserve_init(u, u->device_name) < 0)
            return -1;

    return 0;
}

static int mixer_callback(snd_mixer_elem_t *elem, unsigned int mask) {
    struct userdata *u = snd_mixer_elem_get_callback_private(elem);

    pa_assert(u);
    pa_assert(u->mixer_handle);

    if (mask == SND_CTL_EVENT_MASK_REMOVE)
        return 0;

    if (mask & SND_CTL_EVENT_MASK_VALUE) {
        pa_sink_get_volume(u->sink, TRUE, FALSE);
        pa_sink_get_mute(u->sink, TRUE);
    }

    return 0;
}

static void sink_get_volume_cb(pa_sink *s) {
    struct userdata *u = s->userdata;
    pa_cvolume r;
    char t[PA_CVOLUME_SNPRINT_MAX];

    pa_assert(u);
    pa_assert(u->mixer_path);
    pa_assert(u->mixer_handle);

    if (pa_alsa_path_get_volume(u->mixer_path, u->mixer_handle, &s->channel_map, &r) < 0)
        return;

    /* Shift down by the base volume, so that 0dB becomes maximum volume */
    pa_sw_cvolume_multiply_scalar(&r, &r, s->base_volume);

    pa_log_debug("Read hardware volume: %s", pa_cvolume_snprint(t, sizeof(t), &r));

    if (pa_cvolume_equal(&u->hardware_volume, &r))
        return;

    s->virtual_volume = u->hardware_volume = r;

    if (u->mixer_path->has_dB) {
        pa_cvolume reset;

        /* Hmm, so the hardware volume changed, let's reset our software volume */
        pa_cvolume_reset(&reset, s->sample_spec.channels);
        pa_sink_set_soft_volume(s, &reset);
    }
}

static void sink_set_volume_cb(pa_sink *s) {
    struct userdata *u = s->userdata;
    pa_cvolume r;
    char t[PA_CVOLUME_SNPRINT_MAX];

    pa_assert(u);
    pa_assert(u->mixer_path);
    pa_assert(u->mixer_handle);

    /* Shift up by the base volume */
    pa_sw_cvolume_divide_scalar(&r, &s->virtual_volume, s->base_volume);

    if (pa_alsa_path_set_volume(u->mixer_path, u->mixer_handle, &s->channel_map, &r) < 0)
        return;

    /* Shift down by the base volume, so that 0dB becomes maximum volume */
    pa_sw_cvolume_multiply_scalar(&r, &r, s->base_volume);

    u->hardware_volume = r;

    if (u->mixer_path->has_dB) {

        /* Match exactly what the user requested by software */
        pa_sw_cvolume_divide(&s->soft_volume, &s->virtual_volume, &u->hardware_volume);

        pa_log_debug("Requested volume: %s", pa_cvolume_snprint(t, sizeof(t), &s->virtual_volume));
        pa_log_debug("Got hardware volume: %s", pa_cvolume_snprint(t, sizeof(t), &u->hardware_volume));
        pa_log_debug("Calculated software volume: %s", pa_cvolume_snprint(t, sizeof(t), &s->soft_volume));

    } else {
        pa_log_debug("Wrote hardware volume: %s", pa_cvolume_snprint(t, sizeof(t), &r));

        /* We can't match exactly what the user requested, hence let's
         * at least tell the user about it */

        s->virtual_volume = r;
    }
}

static void sink_get_mute_cb(pa_sink *s) {
    struct userdata *u = s->userdata;
    pa_bool_t b;

    pa_assert(u);
    pa_assert(u->mixer_path);
    pa_assert(u->mixer_handle);

    if (pa_alsa_path_get_mute(u->mixer_path, u->mixer_handle, &b) < 0)
        return;

    s->muted = b;
}

static void sink_set_mute_cb(pa_sink *s) {
    struct userdata *u = s->userdata;

    pa_assert(u);
    pa_assert(u->mixer_path);
    pa_assert(u->mixer_handle);

    pa_alsa_path_set_mute(u->mixer_path, u->mixer_handle, s->muted);
}

static int sink_set_port_cb(pa_sink *s, pa_device_port *p) {
    struct userdata *u = s->userdata;
    pa_alsa_port_data *data;

    pa_assert(u);
    pa_assert(p);
    pa_assert(u->mixer_handle);

    data = PA_DEVICE_PORT_DATA(p);

    pa_assert_se(u->mixer_path = data->path);
    pa_alsa_path_select(u->mixer_path, u->mixer_handle);

    if (u->mixer_path->has_volume && u->mixer_path->has_dB) {
        s->base_volume = pa_sw_volume_from_dB(-u->mixer_path->max_dB);
        s->n_volume_steps = PA_VOLUME_NORM+1;

        if (u->mixer_path->max_dB > 0.0)
            pa_log_info("Fixing base volume to %0.2f dB", pa_sw_volume_to_dB(s->base_volume));
        else
            pa_log_info("No particular base volume set, fixing to 0 dB");
    } else {
        s->base_volume = PA_VOLUME_NORM;
        s->n_volume_steps = u->mixer_path->max_volume - u->mixer_path->min_volume + 1;
    }

    if (data->setting)
        pa_alsa_setting_select(data->setting, u->mixer_handle);

    if (s->set_mute)
        s->set_mute(s);
    if (s->set_volume)
        s->set_volume(s);

    return 0;
}

static void sink_update_requested_latency_cb(pa_sink *s) {
    struct userdata *u = s->userdata;
    size_t before;
    pa_assert(u);

    if (!u->pcm_handle)
        return;

    before = u->hwbuf_unused;
    update_sw_params(u);

    /* Let's check whether we now use only a smaller part of the
    buffer then before. If so, we need to make sure that subsequent
    rewinds are relative to the new maximum fill level and not to the
    current fill level. Thus, let's do a full rewind once, to clear
    things up. */

    if (u->hwbuf_unused > before) {
        pa_log_debug("Requesting rewind due to latency change.");
        pa_sink_request_rewind(s, (size_t) -1);
    }
}

static int process_rewind(struct userdata *u) {
    snd_pcm_sframes_t unused;
    size_t rewind_nbytes, unused_nbytes, limit_nbytes;
    pa_assert(u);

    /* Figure out how much we shall rewind and reset the counter */
    rewind_nbytes = u->sink->thread_info.rewind_nbytes;

    pa_log_debug("Requested to rewind %lu bytes.", (unsigned long) rewind_nbytes);

    if (PA_UNLIKELY((unused = pa_alsa_safe_avail(u->pcm_handle, u->hwbuf_size, &u->sink->sample_spec)) < 0)) {
        pa_log("snd_pcm_avail() failed: %s", pa_alsa_strerror((int) unused));
        return -1;
    }

    unused_nbytes = u->tsched_watermark + (size_t) unused * u->frame_size;

    if (u->hwbuf_size > unused_nbytes)
        limit_nbytes = u->hwbuf_size - unused_nbytes;
    else
        limit_nbytes = 0;

    if (rewind_nbytes > limit_nbytes)
        rewind_nbytes = limit_nbytes;

    if (rewind_nbytes > 0) {
        snd_pcm_sframes_t in_frames, out_frames;

        pa_log_debug("Limited to %lu bytes.", (unsigned long) rewind_nbytes);

        in_frames = (snd_pcm_sframes_t) (rewind_nbytes / u->frame_size);
        pa_log_debug("before: %lu", (unsigned long) in_frames);
        if ((out_frames = snd_pcm_rewind(u->pcm_handle, (snd_pcm_uframes_t) in_frames)) < 0) {
            pa_log("snd_pcm_rewind() failed: %s", pa_alsa_strerror((int) out_frames));
            return -1;
        }
        pa_log_debug("after: %lu", (unsigned long) out_frames);

        rewind_nbytes = (size_t) out_frames * u->frame_size;

        if (rewind_nbytes <= 0)
            pa_log_info("Tried rewind, but was apparently not possible.");
        else {
            u->write_count -= out_frames * u->frame_size;
            pa_log_debug("Rewound %lu bytes.", (unsigned long) rewind_nbytes);
            pa_sink_process_rewind(u->sink, rewind_nbytes);

            u->after_rewind = TRUE;
            return 0;
        }
    } else
        pa_log_debug("Mhmm, actually there is nothing to rewind.");

    pa_sink_process_rewind(u->sink, 0);
    return 0;
}

static void thread_func(void *userdata) {
    struct userdata *u = userdata;
    unsigned short revents = 0;

    pa_assert(u);

    pa_log_debug("Thread starting up");

    if (u->core->realtime_scheduling)
        pa_make_realtime(u->core->realtime_priority);

    pa_thread_mq_install(&u->thread_mq);
    pa_rtpoll_install(u->rtpoll);

    for (;;) {
        int ret;

#ifdef DEBUG_TIMING
        pa_log_debug("Loop");
#endif

        /* Render some data and write it to the dsp */
        if (PA_SINK_IS_OPENED(u->sink->thread_info.state)) {
            int work_done;
            pa_usec_t sleep_usec = 0;

            if (PA_UNLIKELY(u->sink->thread_info.rewind_requested))
                if (process_rewind(u) < 0)
                        goto fail;

            if (u->use_mmap)
                work_done = mmap_write(u, &sleep_usec, revents & POLLOUT);
            else
                work_done = unix_write(u, &sleep_usec, revents & POLLOUT);

            if (work_done < 0)
                goto fail;

/*             pa_log_debug("work_done = %i", work_done); */

            if (work_done) {

                if (u->first) {
                    pa_log_info("Starting playback.");
                    snd_pcm_start(u->pcm_handle);

                    pa_smoother_resume(u->smoother, pa_rtclock_now(), TRUE);
                }

                update_smoother(u);
            }

            if (u->use_tsched) {
                pa_usec_t cusec;

                if (u->since_start <= u->hwbuf_size) {

                    /* USB devices on ALSA seem to hit a buffer
                     * underrun during the first iterations much
                     * quicker then we calculate here, probably due to
                     * the transport latency. To accommodate for that
                     * we artificially decrease the sleep time until
                     * we have filled the buffer at least once
                     * completely.*/

                    pa_log_debug("Cutting sleep time for the initial iterations by half.");
                    sleep_usec /= 2;
                }

                /* OK, the playback buffer is now full, let's
                 * calculate when to wake up next */
/*                 pa_log_debug("Waking up in %0.2fms (sound card clock).", (double) sleep_usec / PA_USEC_PER_MSEC); */

                /* Convert from the sound card time domain to the
                 * system time domain */
                cusec = pa_smoother_translate(u->smoother, pa_rtclock_now(), sleep_usec);

/*                 pa_log_debug("Waking up in %0.2fms (system clock).", (double) cusec / PA_USEC_PER_MSEC); */

                /* We don't trust the conversion, so we wake up whatever comes first */
                pa_rtpoll_set_timer_relative(u->rtpoll, PA_MIN(sleep_usec, cusec));
            }

            u->first = FALSE;
            u->after_rewind = FALSE;

        } else if (u->use_tsched)

            /* OK, we're in an invalid state, let's disable our timers */
            pa_rtpoll_set_timer_disabled(u->rtpoll);

        /* Hmm, nothing to do. Let's sleep */
        if ((ret = pa_rtpoll_run(u->rtpoll, TRUE)) < 0)
            goto fail;

        if (ret == 0)
            goto finish;

        /* Tell ALSA about this and process its response */
        if (PA_SINK_IS_OPENED(u->sink->thread_info.state)) {
            struct pollfd *pollfd;
            int err;
            unsigned n;

            pollfd = pa_rtpoll_item_get_pollfd(u->alsa_rtpoll_item, &n);

            if ((err = snd_pcm_poll_descriptors_revents(u->pcm_handle, pollfd, n, &revents)) < 0) {
                pa_log("snd_pcm_poll_descriptors_revents() failed: %s", pa_alsa_strerror(err));
                goto fail;
            }

            if (revents & ~POLLOUT) {
                if (pa_alsa_recover_from_poll(u->pcm_handle, revents) < 0)
                    goto fail;

                u->first = TRUE;
                u->since_start = 0;
            } else if (revents && u->use_tsched && pa_log_ratelimit())
                pa_log_debug("Wakeup from ALSA!");

        } else
            revents = 0;
    }

fail:
    /* If this was no regular exit from the loop we have to continue
     * processing messages until we received PA_MESSAGE_SHUTDOWN */
    pa_asyncmsgq_post(u->thread_mq.outq, PA_MSGOBJECT(u->core), PA_CORE_MESSAGE_UNLOAD_MODULE, u->module, 0, NULL, NULL);
    pa_asyncmsgq_wait_for(u->thread_mq.inq, PA_MESSAGE_SHUTDOWN);

finish:
    pa_log_debug("Thread shutting down");
}

static void set_sink_name(pa_sink_new_data *data, pa_modargs *ma, const char *device_id, const char *device_name, pa_alsa_mapping *mapping) {
    const char *n;
    char *t;

    pa_assert(data);
    pa_assert(ma);
    pa_assert(device_name);

    if ((n = pa_modargs_get_value(ma, "sink_name", NULL))) {
        pa_sink_new_data_set_name(data, n);
        data->namereg_fail = TRUE;
        return;
    }

    if ((n = pa_modargs_get_value(ma, "name", NULL)))
        data->namereg_fail = TRUE;
    else {
        n = device_id ? device_id : device_name;
        data->namereg_fail = FALSE;
    }

    if (mapping)
        t = pa_sprintf_malloc("alsa_output.%s.%s", n, mapping->name);
    else
        t = pa_sprintf_malloc("alsa_output.%s", n);

    pa_sink_new_data_set_name(data, t);
    pa_xfree(t);
}

static void find_mixer(struct userdata *u, pa_alsa_mapping *mapping, const char *element, pa_bool_t ignore_dB) {

    if (!mapping && !element)
        return;

    if (!(u->mixer_handle = pa_alsa_open_mixer_for_pcm(u->pcm_handle, &u->control_device))) {
        pa_log_info("Failed to find a working mixer device.");
        return;
    }

    if (element) {

        if (!(u->mixer_path = pa_alsa_path_synthesize(element, PA_ALSA_DIRECTION_OUTPUT)))
            goto fail;

        if (pa_alsa_path_probe(u->mixer_path, u->mixer_handle, ignore_dB) < 0)
            goto fail;

        pa_log_debug("Probed mixer path %s:", u->mixer_path->name);
        pa_alsa_path_dump(u->mixer_path);
    } else {

        if (!(u->mixer_path_set = pa_alsa_path_set_new(mapping, PA_ALSA_DIRECTION_OUTPUT)))
            goto fail;

        pa_alsa_path_set_probe(u->mixer_path_set, u->mixer_handle, ignore_dB);

        pa_log_debug("Probed mixer paths:");
        pa_alsa_path_set_dump(u->mixer_path_set);
    }

    return;

fail:

    if (u->mixer_path_set) {
        pa_alsa_path_set_free(u->mixer_path_set);
        u->mixer_path_set = NULL;
    } else if (u->mixer_path) {
        pa_alsa_path_free(u->mixer_path);
        u->mixer_path = NULL;
    }

    if (u->mixer_handle) {
        snd_mixer_close(u->mixer_handle);
        u->mixer_handle = NULL;
    }
}

static int setup_mixer(struct userdata *u, pa_bool_t ignore_dB) {
    pa_assert(u);

    if (!u->mixer_handle)
        return 0;

    if (u->sink->active_port) {
        pa_alsa_port_data *data;

        /* We have a list of supported paths, so let's activate the
         * one that has been chosen as active */

        data = PA_DEVICE_PORT_DATA(u->sink->active_port);
        u->mixer_path = data->path;

        pa_alsa_path_select(data->path, u->mixer_handle);

        if (data->setting)
            pa_alsa_setting_select(data->setting, u->mixer_handle);

    } else {

        if (!u->mixer_path && u->mixer_path_set)
            u->mixer_path = u->mixer_path_set->paths;

        if (u->mixer_path) {
            /* Hmm, we have only a single path, then let's activate it */

            pa_alsa_path_select(u->mixer_path, u->mixer_handle);

            if (u->mixer_path->settings)
                pa_alsa_setting_select(u->mixer_path->settings, u->mixer_handle);
        } else
            return 0;
    }

    if (!u->mixer_path->has_volume)
        pa_log_info("Driver does not support hardware volume control, falling back to software volume control.");
    else {

        if (u->mixer_path->has_dB) {
            pa_log_info("Hardware volume ranges from %0.2f dB to %0.2f dB.", u->mixer_path->min_dB, u->mixer_path->max_dB);

            u->sink->base_volume = pa_sw_volume_from_dB(-u->mixer_path->max_dB);
            u->sink->n_volume_steps = PA_VOLUME_NORM+1;

            if (u->mixer_path->max_dB > 0.0)
                pa_log_info("Fixing base volume to %0.2f dB", pa_sw_volume_to_dB(u->sink->base_volume));
            else
                pa_log_info("No particular base volume set, fixing to 0 dB");

        } else {
            pa_log_info("Hardware volume ranges from %li to %li.", u->mixer_path->min_volume, u->mixer_path->max_volume);
            u->sink->base_volume = PA_VOLUME_NORM;
            u->sink->n_volume_steps = u->mixer_path->max_volume - u->mixer_path->min_volume + 1;
        }

        u->sink->get_volume = sink_get_volume_cb;
        u->sink->set_volume = sink_set_volume_cb;

        u->sink->flags |= PA_SINK_HW_VOLUME_CTRL | (u->mixer_path->has_dB ? PA_SINK_DECIBEL_VOLUME : 0);
        pa_log_info("Using hardware volume control. Hardware dB scale %s.", u->mixer_path->has_dB ? "supported" : "not supported");
    }

    if (!u->mixer_path->has_mute) {
        pa_log_info("Driver does not support hardware mute control, falling back to software mute control.");
    } else {
        u->sink->get_mute = sink_get_mute_cb;
        u->sink->set_mute = sink_set_mute_cb;
        u->sink->flags |= PA_SINK_HW_MUTE_CTRL;
        pa_log_info("Using hardware mute control.");
    }

    u->mixer_fdl = pa_alsa_fdlist_new();

    if (pa_alsa_fdlist_set_mixer(u->mixer_fdl, u->mixer_handle, u->core->mainloop) < 0) {
        pa_log("Failed to initialize file descriptor monitoring");
        return -1;
    }

    if (u->mixer_path_set)
        pa_alsa_path_set_set_callback(u->mixer_path_set, u->mixer_handle, mixer_callback, u);
    else
        pa_alsa_path_set_callback(u->mixer_path, u->mixer_handle, mixer_callback, u);

    return 0;
}

pa_sink *pa_alsa_sink_new(pa_module *m, pa_modargs *ma, const char*driver, pa_card *card, pa_alsa_mapping *mapping) {

    struct userdata *u = NULL;
    const char *dev_id = NULL;
    pa_sample_spec ss, requested_ss;
    pa_channel_map map;
    uint32_t nfrags, hwbuf_size, frag_size, tsched_size, tsched_watermark;
    snd_pcm_uframes_t period_frames, tsched_frames;
    size_t frame_size;
    pa_bool_t use_mmap = TRUE, b, use_tsched = TRUE, d, ignore_dB = FALSE;
    pa_sink_new_data data;
    pa_alsa_profile_set *profile_set = NULL;

    pa_assert(m);
    pa_assert(ma);

    ss = m->core->default_sample_spec;
    map = m->core->default_channel_map;
    if (pa_modargs_get_sample_spec_and_channel_map(ma, &ss, &map, PA_CHANNEL_MAP_ALSA) < 0) {
        pa_log("Failed to parse sample specification and channel map");
        goto fail;
    }

    requested_ss = ss;
    frame_size = pa_frame_size(&ss);

    nfrags = m->core->default_n_fragments;
    frag_size = (uint32_t) pa_usec_to_bytes(m->core->default_fragment_size_msec*PA_USEC_PER_MSEC, &ss);
    if (frag_size <= 0)
        frag_size = (uint32_t) frame_size;
    tsched_size = (uint32_t) pa_usec_to_bytes(DEFAULT_TSCHED_BUFFER_USEC, &ss);
    tsched_watermark = (uint32_t) pa_usec_to_bytes(DEFAULT_TSCHED_WATERMARK_USEC, &ss);

    if (pa_modargs_get_value_u32(ma, "fragments", &nfrags) < 0 ||
        pa_modargs_get_value_u32(ma, "fragment_size", &frag_size) < 0 ||
        pa_modargs_get_value_u32(ma, "tsched_buffer_size", &tsched_size) < 0 ||
        pa_modargs_get_value_u32(ma, "tsched_buffer_watermark", &tsched_watermark) < 0) {
        pa_log("Failed to parse buffer metrics");
        goto fail;
    }

    hwbuf_size = frag_size * nfrags;
    period_frames = frag_size/frame_size;
    tsched_frames = tsched_size/frame_size;

    if (pa_modargs_get_value_boolean(ma, "mmap", &use_mmap) < 0) {
        pa_log("Failed to parse mmap argument.");
        goto fail;
    }

    if (pa_modargs_get_value_boolean(ma, "tsched", &use_tsched) < 0) {
        pa_log("Failed to parse tsched argument.");
        goto fail;
    }

    if (pa_modargs_get_value_boolean(ma, "ignore_dB", &ignore_dB) < 0) {
        pa_log("Failed to parse ignore_dB argument.");
        goto fail;
    }

    if (use_tsched && !pa_rtclock_hrtimer()) {
        pa_log_notice("Disabling timer-based scheduling because high-resolution timers are not available from the kernel.");
        use_tsched = FALSE;
    }

    u = pa_xnew0(struct userdata, 1);
    u->core = m->core;
    u->module = m;
    u->use_mmap = use_mmap;
    u->use_tsched = use_tsched;
    u->first = TRUE;
    u->rtpoll = pa_rtpoll_new();
    pa_thread_mq_init(&u->thread_mq, m->core->mainloop, u->rtpoll);

    u->smoother = pa_smoother_new(
            DEFAULT_TSCHED_BUFFER_USEC*2,
            DEFAULT_TSCHED_BUFFER_USEC*2,
            TRUE,
            TRUE,
            5,
            pa_rtclock_now(),
            TRUE);

    dev_id = pa_modargs_get_value(
            ma, "device_id",
            pa_modargs_get_value(ma, "device", DEFAULT_DEVICE));

    if (reserve_init(u, dev_id) < 0)
        goto fail;

    if (reserve_monitor_init(u, dev_id) < 0)
        goto fail;

    b = use_mmap;
    d = use_tsched;

    if (mapping) {

        if (!(dev_id = pa_modargs_get_value(ma, "device_id", NULL))) {
            pa_log("device_id= not set");
            goto fail;
        }

        if (!(u->pcm_handle = pa_alsa_open_by_device_id_mapping(
                      dev_id,
                      &u->device_name,
                      &ss, &map,
                      SND_PCM_STREAM_PLAYBACK,
                      &nfrags, &period_frames, tsched_frames,
                      &b, &d, mapping)))

            goto fail;

    } else if ((dev_id = pa_modargs_get_value(ma, "device_id", NULL))) {

        if (!(profile_set = pa_alsa_profile_set_new(NULL, &map)))
            goto fail;

        if (!(u->pcm_handle = pa_alsa_open_by_device_id_auto(
                      dev_id,
                      &u->device_name,
                      &ss, &map,
                      SND_PCM_STREAM_PLAYBACK,
                      &nfrags, &period_frames, tsched_frames,
                      &b, &d, profile_set, &mapping)))

            goto fail;

    } else {

        if (!(u->pcm_handle = pa_alsa_open_by_device_string(
                      pa_modargs_get_value(ma, "device", DEFAULT_DEVICE),
                      &u->device_name,
                      &ss, &map,
                      SND_PCM_STREAM_PLAYBACK,
                      &nfrags, &period_frames, tsched_frames,
                      &b, &d, FALSE)))
            goto fail;
    }

    pa_assert(u->device_name);
    pa_log_info("Successfully opened device %s.", u->device_name);

    if (pa_alsa_pcm_is_modem(u->pcm_handle)) {
        pa_log_notice("Device %s is modem, refusing further initialization.", u->device_name);
        goto fail;
    }

    if (mapping)
        pa_log_info("Selected mapping '%s' (%s).", mapping->description, mapping->name);

    if (use_mmap && !b) {
        pa_log_info("Device doesn't support mmap(), falling back to UNIX read/write mode.");
        u->use_mmap = use_mmap = FALSE;
    }

    if (use_tsched && (!b || !d)) {
        pa_log_info("Cannot enable timer-based scheduling, falling back to sound IRQ scheduling.");
        u->use_tsched = use_tsched = FALSE;
    }

    if (use_tsched && !pa_alsa_pcm_is_hw(u->pcm_handle)) {
        pa_log_info("Device is not a hardware device, disabling timer-based scheduling.");
        u->use_tsched = use_tsched = FALSE;
    }

    if (u->use_mmap)
        pa_log_info("Successfully enabled mmap() mode.");

    if (u->use_tsched)
        pa_log_info("Successfully enabled timer-based scheduling mode.");

    /* ALSA might tweak the sample spec, so recalculate the frame size */
    frame_size = pa_frame_size(&ss);

    find_mixer(u, mapping, pa_modargs_get_value(ma, "control", NULL), ignore_dB);

    pa_sink_new_data_init(&data);
    data.driver = driver;
    data.module = m;
    data.card = card;
    set_sink_name(&data, ma, dev_id, u->device_name, mapping);
    pa_sink_new_data_set_sample_spec(&data, &ss);
    pa_sink_new_data_set_channel_map(&data, &map);

    pa_alsa_init_proplist_pcm(m->core, data.proplist, u->pcm_handle);
    pa_proplist_sets(data.proplist, PA_PROP_DEVICE_STRING, u->device_name);
    pa_proplist_setf(data.proplist, PA_PROP_DEVICE_BUFFERING_BUFFER_SIZE, "%lu", (unsigned long) (period_frames * frame_size * nfrags));
    pa_proplist_setf(data.proplist, PA_PROP_DEVICE_BUFFERING_FRAGMENT_SIZE, "%lu", (unsigned long) (period_frames * frame_size));
    pa_proplist_sets(data.proplist, PA_PROP_DEVICE_ACCESS_MODE, u->use_tsched ? "mmap+timer" : (u->use_mmap ? "mmap" : "serial"));

    if (mapping) {
        pa_proplist_sets(data.proplist, PA_PROP_DEVICE_PROFILE_NAME, mapping->name);
        pa_proplist_sets(data.proplist, PA_PROP_DEVICE_PROFILE_DESCRIPTION, mapping->description);
    }

    pa_alsa_init_description(data.proplist);

    if (u->control_device)
        pa_alsa_init_proplist_ctl(data.proplist, u->control_device);

    if (pa_modargs_get_proplist(ma, "sink_properties", data.proplist, PA_UPDATE_REPLACE) < 0) {
        pa_log("Invalid properties");
        pa_sink_new_data_done(&data);
        goto fail;
    }

    if (u->mixer_path_set)
        pa_alsa_add_ports(&data.ports, u->mixer_path_set);

    u->sink = pa_sink_new(m->core, &data, PA_SINK_HARDWARE|PA_SINK_LATENCY|(u->use_tsched ? PA_SINK_DYNAMIC_LATENCY : 0));
    pa_sink_new_data_done(&data);

    if (!u->sink) {
        pa_log("Failed to create sink object");
        goto fail;
    }

    u->sink->parent.process_msg = sink_process_msg;
    u->sink->update_requested_latency = sink_update_requested_latency_cb;
    u->sink->set_state = sink_set_state_cb;
    u->sink->set_port = sink_set_port_cb;
    u->sink->userdata = u;

    pa_sink_set_asyncmsgq(u->sink, u->thread_mq.inq);
    pa_sink_set_rtpoll(u->sink, u->rtpoll);

    u->frame_size = frame_size;
    u->fragment_size = frag_size = (uint32_t) (period_frames * frame_size);
    u->nfragments = nfrags;
    u->hwbuf_size = u->fragment_size * nfrags;
    u->tsched_watermark = pa_usec_to_bytes_round_up(pa_bytes_to_usec_round_up(tsched_watermark, &requested_ss), &u->sink->sample_spec);
    pa_cvolume_mute(&u->hardware_volume, u->sink->sample_spec.channels);

    pa_log_info("Using %u fragments of size %lu bytes, buffer time is %0.2fms",
                nfrags, (long unsigned) u->fragment_size,
                (double) pa_bytes_to_usec(u->hwbuf_size, &ss) / PA_USEC_PER_MSEC);

    pa_sink_set_max_request(u->sink, u->hwbuf_size);
    pa_sink_set_max_rewind(u->sink, u->hwbuf_size);

    if (u->use_tsched) {
        u->watermark_step = pa_usec_to_bytes(TSCHED_WATERMARK_STEP_USEC, &u->sink->sample_spec);

        fix_min_sleep_wakeup(u);
        fix_tsched_watermark(u);

        pa_sink_set_latency_range(u->sink,
                                  0,
                                  pa_bytes_to_usec(u->hwbuf_size, &ss));

        pa_log_info("Time scheduling watermark is %0.2fms",
                    (double) pa_bytes_to_usec(u->tsched_watermark, &ss) / PA_USEC_PER_MSEC);
    } else
        pa_sink_set_fixed_latency(u->sink, pa_bytes_to_usec(u->hwbuf_size, &ss));

    reserve_update(u);

    if (update_sw_params(u) < 0)
        goto fail;

    if (setup_mixer(u, ignore_dB) < 0)
        goto fail;

    pa_alsa_dump(PA_LOG_DEBUG, u->pcm_handle);

    if (!(u->thread = pa_thread_new(thread_func, u))) {
        pa_log("Failed to create thread.");
        goto fail;
    }

    /* Get initial mixer settings */
    if (data.volume_is_set) {
        if (u->sink->set_volume)
            u->sink->set_volume(u->sink);
    } else {
        if (u->sink->get_volume)
            u->sink->get_volume(u->sink);
    }

    if (data.muted_is_set) {
        if (u->sink->set_mute)
            u->sink->set_mute(u->sink);
    } else {
        if (u->sink->get_mute)
            u->sink->get_mute(u->sink);
    }

    pa_sink_put(u->sink);

    if (profile_set)
        pa_alsa_profile_set_free(profile_set);

    return u->sink;

fail:

    if (u)
        userdata_free(u);

    if (profile_set)
        pa_alsa_profile_set_free(profile_set);

    return NULL;
}

static void userdata_free(struct userdata *u) {
    pa_assert(u);

    if (u->sink)
        pa_sink_unlink(u->sink);

    if (u->thread) {
        pa_asyncmsgq_send(u->thread_mq.inq, NULL, PA_MESSAGE_SHUTDOWN, NULL, 0, NULL);
        pa_thread_free(u->thread);
    }

    pa_thread_mq_done(&u->thread_mq);

    if (u->sink)
        pa_sink_unref(u->sink);

    if (u->memchunk.memblock)
        pa_memblock_unref(u->memchunk.memblock);

    if (u->alsa_rtpoll_item)
        pa_rtpoll_item_free(u->alsa_rtpoll_item);

    if (u->rtpoll)
        pa_rtpoll_free(u->rtpoll);

    if (u->pcm_handle) {
        snd_pcm_drop(u->pcm_handle);
        snd_pcm_close(u->pcm_handle);
    }

    if (u->mixer_fdl)
        pa_alsa_fdlist_free(u->mixer_fdl);

    if (u->mixer_path_set)
        pa_alsa_path_set_free(u->mixer_path_set);
    else if (u->mixer_path)
        pa_alsa_path_free(u->mixer_path);

    if (u->mixer_handle)
        snd_mixer_close(u->mixer_handle);

    if (u->smoother)
        pa_smoother_free(u->smoother);

    reserve_done(u);
    monitor_done(u);

    pa_xfree(u->device_name);
    pa_xfree(u->control_device);
    pa_xfree(u);
}

void pa_alsa_sink_free(pa_sink *s) {
    struct userdata *u;

    pa_sink_assert_ref(s);
    pa_assert_se(u = s->userdata);

    userdata_free(u);
}