xref: /freebsd/sys/dev/sound/pcm/channel.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
5  * Portions Copyright (c) Ryan Beasley <ryan.beasley@gmail.com> - GSoC 2006
6  * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
7  * Portions Copyright (c) Luigi Rizzo <luigi@FreeBSD.org> - 1997-99
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include "opt_isa.h"
33 
34 #ifdef HAVE_KERNEL_OPTION_HEADERS
35 #include "opt_snd.h"
36 #endif
37 
38 #include <dev/sound/pcm/sound.h>
39 #include <dev/sound/pcm/vchan.h>
40 
41 #include "feeder_if.h"
42 
43 SND_DECLARE_FILE("$FreeBSD$");
44 
45 int report_soft_formats = 1;
46 SYSCTL_INT(_hw_snd, OID_AUTO, report_soft_formats, CTLFLAG_RW,
47 	&report_soft_formats, 0, "report software-emulated formats");
48 
49 int report_soft_matrix = 1;
50 SYSCTL_INT(_hw_snd, OID_AUTO, report_soft_matrix, CTLFLAG_RW,
51 	&report_soft_matrix, 0, "report software-emulated channel matrixing");
52 
53 int chn_latency = CHN_LATENCY_DEFAULT;
54 
55 static int
56 sysctl_hw_snd_latency(SYSCTL_HANDLER_ARGS)
57 {
58 	int err, val;
59 
60 	val = chn_latency;
61 	err = sysctl_handle_int(oidp, &val, 0, req);
62 	if (err != 0 || req->newptr == NULL)
63 		return err;
64 	if (val < CHN_LATENCY_MIN || val > CHN_LATENCY_MAX)
65 		err = EINVAL;
66 	else
67 		chn_latency = val;
68 
69 	return err;
70 }
71 SYSCTL_PROC(_hw_snd, OID_AUTO, latency, CTLTYPE_INT | CTLFLAG_RWTUN,
72 	0, sizeof(int), sysctl_hw_snd_latency, "I",
73 	"buffering latency (0=low ... 10=high)");
74 
75 int chn_latency_profile = CHN_LATENCY_PROFILE_DEFAULT;
76 
77 static int
78 sysctl_hw_snd_latency_profile(SYSCTL_HANDLER_ARGS)
79 {
80 	int err, val;
81 
82 	val = chn_latency_profile;
83 	err = sysctl_handle_int(oidp, &val, 0, req);
84 	if (err != 0 || req->newptr == NULL)
85 		return err;
86 	if (val < CHN_LATENCY_PROFILE_MIN || val > CHN_LATENCY_PROFILE_MAX)
87 		err = EINVAL;
88 	else
89 		chn_latency_profile = val;
90 
91 	return err;
92 }
93 SYSCTL_PROC(_hw_snd, OID_AUTO, latency_profile, CTLTYPE_INT | CTLFLAG_RWTUN,
94 	0, sizeof(int), sysctl_hw_snd_latency_profile, "I",
95 	"buffering latency profile (0=aggressive 1=safe)");
96 
97 static int chn_timeout = CHN_TIMEOUT;
98 
99 static int
100 sysctl_hw_snd_timeout(SYSCTL_HANDLER_ARGS)
101 {
102 	int err, val;
103 
104 	val = chn_timeout;
105 	err = sysctl_handle_int(oidp, &val, 0, req);
106 	if (err != 0 || req->newptr == NULL)
107 		return err;
108 	if (val < CHN_TIMEOUT_MIN || val > CHN_TIMEOUT_MAX)
109 		err = EINVAL;
110 	else
111 		chn_timeout = val;
112 
113 	return err;
114 }
115 SYSCTL_PROC(_hw_snd, OID_AUTO, timeout, CTLTYPE_INT | CTLFLAG_RWTUN,
116 	0, sizeof(int), sysctl_hw_snd_timeout, "I",
117 	"interrupt timeout (1 - 10) seconds");
118 
119 static int chn_vpc_autoreset = 1;
120 SYSCTL_INT(_hw_snd, OID_AUTO, vpc_autoreset, CTLFLAG_RWTUN,
121 	&chn_vpc_autoreset, 0, "automatically reset channels volume to 0db");
122 
123 static int chn_vol_0db_pcm = SND_VOL_0DB_PCM;
124 
125 static void
126 chn_vpc_proc(int reset, int db)
127 {
128 	struct snddev_info *d;
129 	struct pcm_channel *c;
130 	int i;
131 
132 	for (i = 0; pcm_devclass != NULL &&
133 	    i < devclass_get_maxunit(pcm_devclass); i++) {
134 		d = devclass_get_softc(pcm_devclass, i);
135 		if (!PCM_REGISTERED(d))
136 			continue;
137 		PCM_LOCK(d);
138 		PCM_WAIT(d);
139 		PCM_ACQUIRE(d);
140 		CHN_FOREACH(c, d, channels.pcm) {
141 			CHN_LOCK(c);
142 			CHN_SETVOLUME(c, SND_VOL_C_PCM, SND_CHN_T_VOL_0DB, db);
143 			if (reset != 0)
144 				chn_vpc_reset(c, SND_VOL_C_PCM, 1);
145 			CHN_UNLOCK(c);
146 		}
147 		PCM_RELEASE(d);
148 		PCM_UNLOCK(d);
149 	}
150 }
151 
152 static int
153 sysctl_hw_snd_vpc_0db(SYSCTL_HANDLER_ARGS)
154 {
155 	int err, val;
156 
157 	val = chn_vol_0db_pcm;
158 	err = sysctl_handle_int(oidp, &val, 0, req);
159 	if (err != 0 || req->newptr == NULL)
160 		return (err);
161 	if (val < SND_VOL_0DB_MIN || val > SND_VOL_0DB_MAX)
162 		return (EINVAL);
163 
164 	chn_vol_0db_pcm = val;
165 	chn_vpc_proc(0, val);
166 
167 	return (0);
168 }
169 SYSCTL_PROC(_hw_snd, OID_AUTO, vpc_0db, CTLTYPE_INT | CTLFLAG_RWTUN,
170 	0, sizeof(int), sysctl_hw_snd_vpc_0db, "I",
171 	"0db relative level");
172 
173 static int
174 sysctl_hw_snd_vpc_reset(SYSCTL_HANDLER_ARGS)
175 {
176 	int err, val;
177 
178 	val = 0;
179 	err = sysctl_handle_int(oidp, &val, 0, req);
180 	if (err != 0 || req->newptr == NULL || val == 0)
181 		return (err);
182 
183 	chn_vol_0db_pcm = SND_VOL_0DB_PCM;
184 	chn_vpc_proc(1, SND_VOL_0DB_PCM);
185 
186 	return (0);
187 }
188 SYSCTL_PROC(_hw_snd, OID_AUTO, vpc_reset, CTLTYPE_INT | CTLFLAG_RW,
189 	0, sizeof(int), sysctl_hw_snd_vpc_reset, "I",
190 	"reset volume on all channels");
191 
192 static int chn_usefrags = 0;
193 static int chn_syncdelay = -1;
194 
195 SYSCTL_INT(_hw_snd, OID_AUTO, usefrags, CTLFLAG_RWTUN,
196 	&chn_usefrags, 0, "prefer setfragments() over setblocksize()");
197 SYSCTL_INT(_hw_snd, OID_AUTO, syncdelay, CTLFLAG_RWTUN,
198 	&chn_syncdelay, 0,
199 	"append (0-1000) millisecond trailing buffer delay on each sync");
200 
201 /**
202  * @brief Channel sync group lock
203  *
204  * Clients should acquire this lock @b without holding any channel locks
205  * before touching syncgroups or the main syncgroup list.
206  */
207 struct mtx snd_pcm_syncgroups_mtx;
208 MTX_SYSINIT(pcm_syncgroup, &snd_pcm_syncgroups_mtx, "PCM channel sync group lock", MTX_DEF);
209 /**
210  * @brief syncgroups' master list
211  *
212  * Each time a channel syncgroup is created, it's added to this list.  This
213  * list should only be accessed with @sa snd_pcm_syncgroups_mtx held.
214  *
215  * See SNDCTL_DSP_SYNCGROUP for more information.
216  */
217 struct pcm_synclist snd_pcm_syncgroups = SLIST_HEAD_INITIALIZER(snd_pcm_syncgroups);
218 
219 static void
220 chn_lockinit(struct pcm_channel *c, int dir)
221 {
222 	switch (dir) {
223 	case PCMDIR_PLAY:
224 		c->lock = snd_mtxcreate(c->name, "pcm play channel");
225 		cv_init(&c->intr_cv, "pcmwr");
226 		break;
227 	case PCMDIR_PLAY_VIRTUAL:
228 		c->lock = snd_mtxcreate(c->name, "pcm virtual play channel");
229 		cv_init(&c->intr_cv, "pcmwrv");
230 		break;
231 	case PCMDIR_REC:
232 		c->lock = snd_mtxcreate(c->name, "pcm record channel");
233 		cv_init(&c->intr_cv, "pcmrd");
234 		break;
235 	case PCMDIR_REC_VIRTUAL:
236 		c->lock = snd_mtxcreate(c->name, "pcm virtual record channel");
237 		cv_init(&c->intr_cv, "pcmrdv");
238 		break;
239 	default:
240 		panic("%s(): Invalid direction=%d", __func__, dir);
241 		break;
242 	}
243 
244 	cv_init(&c->cv, "pcmchn");
245 }
246 
247 static void
248 chn_lockdestroy(struct pcm_channel *c)
249 {
250 	CHN_LOCKASSERT(c);
251 
252 	CHN_BROADCAST(&c->cv);
253 	CHN_BROADCAST(&c->intr_cv);
254 
255 	cv_destroy(&c->cv);
256 	cv_destroy(&c->intr_cv);
257 
258 	snd_mtxfree(c->lock);
259 }
260 
261 /**
262  * @brief Determine channel is ready for I/O
263  *
264  * @retval 1 = ready for I/O
265  * @retval 0 = not ready for I/O
266  */
267 static int
268 chn_polltrigger(struct pcm_channel *c)
269 {
270 	struct snd_dbuf *bs = c->bufsoft;
271 	u_int delta;
272 
273 	CHN_LOCKASSERT(c);
274 
275 	if (c->flags & CHN_F_MMAP) {
276 		if (sndbuf_getprevtotal(bs) < c->lw)
277 			delta = c->lw;
278 		else
279 			delta = sndbuf_gettotal(bs) - sndbuf_getprevtotal(bs);
280 	} else {
281 		if (c->direction == PCMDIR_PLAY)
282 			delta = sndbuf_getfree(bs);
283 		else
284 			delta = sndbuf_getready(bs);
285 	}
286 
287 	return ((delta < c->lw) ? 0 : 1);
288 }
289 
290 static void
291 chn_pollreset(struct pcm_channel *c)
292 {
293 
294 	CHN_LOCKASSERT(c);
295 	sndbuf_updateprevtotal(c->bufsoft);
296 }
297 
298 static void
299 chn_wakeup(struct pcm_channel *c)
300 {
301 	struct snd_dbuf *bs;
302 	struct pcm_channel *ch;
303 
304 	CHN_LOCKASSERT(c);
305 
306 	bs = c->bufsoft;
307 
308 	if (CHN_EMPTY(c, children.busy)) {
309 		if (SEL_WAITING(sndbuf_getsel(bs)) && chn_polltrigger(c))
310 			selwakeuppri(sndbuf_getsel(bs), PRIBIO);
311 		if (c->flags & CHN_F_SLEEPING) {
312 			/*
313 			 * Ok, I can just panic it right here since it is
314 			 * quite obvious that we never allow multiple waiters
315 			 * from userland. I'm too generous...
316 			 */
317 			CHN_BROADCAST(&c->intr_cv);
318 		}
319 	} else {
320 		CHN_FOREACH(ch, c, children.busy) {
321 			CHN_LOCK(ch);
322 			chn_wakeup(ch);
323 			CHN_UNLOCK(ch);
324 		}
325 	}
326 }
327 
328 static int
329 chn_sleep(struct pcm_channel *c, int timeout)
330 {
331 	int ret;
332 
333 	CHN_LOCKASSERT(c);
334 
335 	if (c->flags & CHN_F_DEAD)
336 		return (EINVAL);
337 
338 	c->flags |= CHN_F_SLEEPING;
339 	ret = cv_timedwait_sig(&c->intr_cv, c->lock, timeout);
340 	c->flags &= ~CHN_F_SLEEPING;
341 
342 	return ((c->flags & CHN_F_DEAD) ? EINVAL : ret);
343 }
344 
345 /*
346  * chn_dmaupdate() tracks the status of a dma transfer,
347  * updating pointers.
348  */
349 
350 static unsigned int
351 chn_dmaupdate(struct pcm_channel *c)
352 {
353 	struct snd_dbuf *b = c->bufhard;
354 	unsigned int delta, old, hwptr, amt;
355 
356 	KASSERT(sndbuf_getsize(b) > 0, ("bufsize == 0"));
357 	CHN_LOCKASSERT(c);
358 
359 	old = sndbuf_gethwptr(b);
360 	hwptr = chn_getptr(c);
361 	delta = (sndbuf_getsize(b) + hwptr - old) % sndbuf_getsize(b);
362 	sndbuf_sethwptr(b, hwptr);
363 
364 	if (c->direction == PCMDIR_PLAY) {
365 		amt = min(delta, sndbuf_getready(b));
366 		amt -= amt % sndbuf_getalign(b);
367 		if (amt > 0)
368 			sndbuf_dispose(b, NULL, amt);
369 	} else {
370 		amt = min(delta, sndbuf_getfree(b));
371 		amt -= amt % sndbuf_getalign(b);
372 		if (amt > 0)
373 		       sndbuf_acquire(b, NULL, amt);
374 	}
375 	if (snd_verbose > 3 && CHN_STARTED(c) && delta == 0) {
376 		device_printf(c->dev, "WARNING: %s DMA completion "
377 			"too fast/slow ! hwptr=%u, old=%u "
378 			"delta=%u amt=%u ready=%u free=%u\n",
379 			CHN_DIRSTR(c), hwptr, old, delta, amt,
380 			sndbuf_getready(b), sndbuf_getfree(b));
381 	}
382 
383 	return delta;
384 }
385 
386 static void
387 chn_wrfeed(struct pcm_channel *c)
388 {
389     	struct snd_dbuf *b = c->bufhard;
390     	struct snd_dbuf *bs = c->bufsoft;
391 	unsigned int amt, want, wasfree;
392 
393 	CHN_LOCKASSERT(c);
394 
395 	if ((c->flags & CHN_F_MMAP) && !(c->flags & CHN_F_CLOSING))
396 		sndbuf_acquire(bs, NULL, sndbuf_getfree(bs));
397 
398 	wasfree = sndbuf_getfree(b);
399 	want = min(sndbuf_getsize(b),
400 	    imax(0, sndbuf_xbytes(sndbuf_getsize(bs), bs, b) -
401 	     sndbuf_getready(b)));
402 	amt = min(wasfree, want);
403 	if (amt > 0)
404 		sndbuf_feed(bs, b, c, c->feeder, amt);
405 
406 	/*
407 	 * Possible xruns. There should be no empty space left in buffer.
408 	 */
409 	if (sndbuf_getready(b) < want)
410 		c->xruns++;
411 
412 	if (sndbuf_getfree(b) < wasfree)
413 		chn_wakeup(c);
414 }
415 
416 #if 0
417 static void
418 chn_wrupdate(struct pcm_channel *c)
419 {
420 
421 	CHN_LOCKASSERT(c);
422 	KASSERT(c->direction == PCMDIR_PLAY, ("%s(): bad channel", __func__));
423 
424 	if ((c->flags & (CHN_F_MMAP | CHN_F_VIRTUAL)) || CHN_STOPPED(c))
425 		return;
426 	chn_dmaupdate(c);
427 	chn_wrfeed(c);
428 	/* tell the driver we've updated the primary buffer */
429 	chn_trigger(c, PCMTRIG_EMLDMAWR);
430 }
431 #endif
432 
433 static void
434 chn_wrintr(struct pcm_channel *c)
435 {
436 
437 	CHN_LOCKASSERT(c);
438 	/* update pointers in primary buffer */
439 	chn_dmaupdate(c);
440 	/* ...and feed from secondary to primary */
441 	chn_wrfeed(c);
442 	/* tell the driver we've updated the primary buffer */
443 	chn_trigger(c, PCMTRIG_EMLDMAWR);
444 }
445 
446 /*
447  * user write routine - uiomove data into secondary buffer, trigger if necessary
448  * if blocking, sleep, rinse and repeat.
449  *
450  * called externally, so must handle locking
451  */
452 
453 int
454 chn_write(struct pcm_channel *c, struct uio *buf)
455 {
456 	struct snd_dbuf *bs = c->bufsoft;
457 	void *off;
458 	int ret, timeout, sz, t, p;
459 
460 	CHN_LOCKASSERT(c);
461 
462 	ret = 0;
463 	timeout = chn_timeout * hz;
464 
465 	while (ret == 0 && buf->uio_resid > 0) {
466 		sz = min(buf->uio_resid, sndbuf_getfree(bs));
467 		if (sz > 0) {
468 			/*
469 			 * The following assumes that the free space in
470 			 * the buffer can never be less around the
471 			 * unlock-uiomove-lock sequence.
472 			 */
473 			while (ret == 0 && sz > 0) {
474 				p = sndbuf_getfreeptr(bs);
475 				t = min(sz, sndbuf_getsize(bs) - p);
476 				off = sndbuf_getbufofs(bs, p);
477 				CHN_UNLOCK(c);
478 				ret = uiomove(off, t, buf);
479 				CHN_LOCK(c);
480 				sz -= t;
481 				sndbuf_acquire(bs, NULL, t);
482 			}
483 			ret = 0;
484 			if (CHN_STOPPED(c) && !(c->flags & CHN_F_NOTRIGGER)) {
485 				ret = chn_start(c, 0);
486 				if (ret != 0)
487 					c->flags |= CHN_F_DEAD;
488 			}
489 		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER)) {
490 			/**
491 			 * @todo Evaluate whether EAGAIN is truly desirable.
492 			 * 	 4Front drivers behave like this, but I'm
493 			 * 	 not sure if it at all violates the "write
494 			 * 	 should be allowed to block" model.
495 			 *
496 			 * 	 The idea is that, while set with CHN_F_NOTRIGGER,
497 			 * 	 a channel isn't playing, *but* without this we
498 			 * 	 end up with "interrupt timeout / channel dead".
499 			 */
500 			ret = EAGAIN;
501 		} else {
502    			ret = chn_sleep(c, timeout);
503 			if (ret == EAGAIN) {
504 				ret = EINVAL;
505 				c->flags |= CHN_F_DEAD;
506 				device_printf(c->dev, "%s(): %s: "
507 				    "play interrupt timeout, channel dead\n",
508 				    __func__, c->name);
509 			} else if (ret == ERESTART || ret == EINTR)
510 				c->flags |= CHN_F_ABORTING;
511 		}
512 	}
513 
514 	return (ret);
515 }
516 
517 /*
518  * Feed new data from the read buffer. Can be called in the bottom half.
519  */
520 static void
521 chn_rdfeed(struct pcm_channel *c)
522 {
523     	struct snd_dbuf *b = c->bufhard;
524     	struct snd_dbuf *bs = c->bufsoft;
525 	unsigned int amt;
526 
527 	CHN_LOCKASSERT(c);
528 
529 	if (c->flags & CHN_F_MMAP)
530 		sndbuf_dispose(bs, NULL, sndbuf_getready(bs));
531 
532 	amt = sndbuf_getfree(bs);
533 	if (amt > 0)
534 		sndbuf_feed(b, bs, c, c->feeder, amt);
535 
536 	amt = sndbuf_getready(b);
537 	if (amt > 0) {
538 		c->xruns++;
539 		sndbuf_dispose(b, NULL, amt);
540 	}
541 
542 	if (sndbuf_getready(bs) > 0)
543 		chn_wakeup(c);
544 }
545 
546 #if 0
547 static void
548 chn_rdupdate(struct pcm_channel *c)
549 {
550 
551 	CHN_LOCKASSERT(c);
552 	KASSERT(c->direction == PCMDIR_REC, ("chn_rdupdate on bad channel"));
553 
554 	if ((c->flags & (CHN_F_MMAP | CHN_F_VIRTUAL)) || CHN_STOPPED(c))
555 		return;
556 	chn_trigger(c, PCMTRIG_EMLDMARD);
557 	chn_dmaupdate(c);
558 	chn_rdfeed(c);
559 }
560 #endif
561 
562 /* read interrupt routine. Must be called with interrupts blocked. */
563 static void
564 chn_rdintr(struct pcm_channel *c)
565 {
566 
567 	CHN_LOCKASSERT(c);
568 	/* tell the driver to update the primary buffer if non-dma */
569 	chn_trigger(c, PCMTRIG_EMLDMARD);
570 	/* update pointers in primary buffer */
571 	chn_dmaupdate(c);
572 	/* ...and feed from primary to secondary */
573 	chn_rdfeed(c);
574 }
575 
576 /*
577  * user read routine - trigger if necessary, uiomove data from secondary buffer
578  * if blocking, sleep, rinse and repeat.
579  *
580  * called externally, so must handle locking
581  */
582 
583 int
584 chn_read(struct pcm_channel *c, struct uio *buf)
585 {
586 	struct snd_dbuf *bs = c->bufsoft;
587 	void *off;
588 	int ret, timeout, sz, t, p;
589 
590 	CHN_LOCKASSERT(c);
591 
592 	if (CHN_STOPPED(c) && !(c->flags & CHN_F_NOTRIGGER)) {
593 		ret = chn_start(c, 0);
594 		if (ret != 0) {
595 			c->flags |= CHN_F_DEAD;
596 			return (ret);
597 		}
598 	}
599 
600 	ret = 0;
601 	timeout = chn_timeout * hz;
602 
603 	while (ret == 0 && buf->uio_resid > 0) {
604 		sz = min(buf->uio_resid, sndbuf_getready(bs));
605 		if (sz > 0) {
606 			/*
607 			 * The following assumes that the free space in
608 			 * the buffer can never be less around the
609 			 * unlock-uiomove-lock sequence.
610 			 */
611 			while (ret == 0 && sz > 0) {
612 				p = sndbuf_getreadyptr(bs);
613 				t = min(sz, sndbuf_getsize(bs) - p);
614 				off = sndbuf_getbufofs(bs, p);
615 				CHN_UNLOCK(c);
616 				ret = uiomove(off, t, buf);
617 				CHN_LOCK(c);
618 				sz -= t;
619 				sndbuf_dispose(bs, NULL, t);
620 			}
621 			ret = 0;
622 		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER))
623 			ret = EAGAIN;
624 		else {
625    			ret = chn_sleep(c, timeout);
626 			if (ret == EAGAIN) {
627 				ret = EINVAL;
628 				c->flags |= CHN_F_DEAD;
629 				device_printf(c->dev, "%s(): %s: "
630 				    "record interrupt timeout, channel dead\n",
631 				    __func__, c->name);
632 			} else if (ret == ERESTART || ret == EINTR)
633 				c->flags |= CHN_F_ABORTING;
634 		}
635 	}
636 
637 	return (ret);
638 }
639 
640 void
641 chn_intr_locked(struct pcm_channel *c)
642 {
643 
644 	CHN_LOCKASSERT(c);
645 
646 	c->interrupts++;
647 
648 	if (c->direction == PCMDIR_PLAY)
649 		chn_wrintr(c);
650 	else
651 		chn_rdintr(c);
652 }
653 
654 void
655 chn_intr(struct pcm_channel *c)
656 {
657 
658 	if (CHN_LOCKOWNED(c)) {
659 		chn_intr_locked(c);
660 		return;
661 	}
662 
663 	CHN_LOCK(c);
664 	chn_intr_locked(c);
665 	CHN_UNLOCK(c);
666 }
667 
668 u_int32_t
669 chn_start(struct pcm_channel *c, int force)
670 {
671 	u_int32_t i, j;
672 	struct snd_dbuf *b = c->bufhard;
673 	struct snd_dbuf *bs = c->bufsoft;
674 	int err;
675 
676 	CHN_LOCKASSERT(c);
677 	/* if we're running, or if we're prevented from triggering, bail */
678 	if (CHN_STARTED(c) || ((c->flags & CHN_F_NOTRIGGER) && !force))
679 		return (EINVAL);
680 
681 	err = 0;
682 
683 	if (force) {
684 		i = 1;
685 		j = 0;
686 	} else {
687 		if (c->direction == PCMDIR_REC) {
688 			i = sndbuf_getfree(bs);
689 			j = (i > 0) ? 1 : sndbuf_getready(b);
690 		} else {
691 			if (sndbuf_getfree(bs) == 0) {
692 				i = 1;
693 				j = 0;
694 			} else {
695 				struct snd_dbuf *pb;
696 
697 				pb = CHN_BUF_PARENT(c, b);
698 				i = sndbuf_xbytes(sndbuf_getready(bs), bs, pb);
699 				j = sndbuf_getalign(pb);
700 			}
701 		}
702 		if (snd_verbose > 3 && CHN_EMPTY(c, children))
703 			device_printf(c->dev, "%s(): %s (%s) threshold "
704 			    "i=%d j=%d\n", __func__, CHN_DIRSTR(c),
705 			    (c->flags & CHN_F_VIRTUAL) ? "virtual" :
706 			    "hardware", i, j);
707 	}
708 
709 	if (i >= j) {
710 		c->flags |= CHN_F_TRIGGERED;
711 		sndbuf_setrun(b, 1);
712 		if (c->flags & CHN_F_CLOSING)
713 			c->feedcount = 2;
714 		else {
715 			c->feedcount = 0;
716 			c->interrupts = 0;
717 			c->xruns = 0;
718 		}
719 		if (c->parentchannel == NULL) {
720 			if (c->direction == PCMDIR_PLAY)
721 				sndbuf_fillsilence_rl(b,
722 				    sndbuf_xbytes(sndbuf_getsize(bs), bs, b));
723 			if (snd_verbose > 3)
724 				device_printf(c->dev,
725 				    "%s(): %s starting! (%s/%s) "
726 				    "(ready=%d force=%d i=%d j=%d "
727 				    "intrtimeout=%u latency=%dms)\n",
728 				    __func__,
729 				    (c->flags & CHN_F_HAS_VCHAN) ?
730 				    "VCHAN PARENT" : "HW", CHN_DIRSTR(c),
731 				    (c->flags & CHN_F_CLOSING) ? "closing" :
732 				    "running",
733 				    sndbuf_getready(b),
734 				    force, i, j, c->timeout,
735 				    (sndbuf_getsize(b) * 1000) /
736 				    (sndbuf_getalign(b) * sndbuf_getspd(b)));
737 		}
738 		err = chn_trigger(c, PCMTRIG_START);
739 	}
740 
741 	return (err);
742 }
743 
744 void
745 chn_resetbuf(struct pcm_channel *c)
746 {
747 	struct snd_dbuf *b = c->bufhard;
748 	struct snd_dbuf *bs = c->bufsoft;
749 
750 	c->blocks = 0;
751 	sndbuf_reset(b);
752 	sndbuf_reset(bs);
753 }
754 
755 /*
756  * chn_sync waits until the space in the given channel goes above
757  * a threshold. The threshold is checked against fl or rl respectively.
758  * Assume that the condition can become true, do not check here...
759  */
760 int
761 chn_sync(struct pcm_channel *c, int threshold)
762 {
763     	struct snd_dbuf *b, *bs;
764 	int ret, count, hcount, minflush, resid, residp, syncdelay, blksz;
765 	u_int32_t cflag;
766 
767 	CHN_LOCKASSERT(c);
768 
769 	if (c->direction != PCMDIR_PLAY)
770 		return (EINVAL);
771 
772 	bs = c->bufsoft;
773 
774 	if ((c->flags & (CHN_F_DEAD | CHN_F_ABORTING)) ||
775 	    (threshold < 1 && sndbuf_getready(bs) < 1))
776 		return (0);
777 
778 	/* if we haven't yet started and nothing is buffered, else start*/
779 	if (CHN_STOPPED(c)) {
780 		if (threshold > 0 || sndbuf_getready(bs) > 0) {
781 			ret = chn_start(c, 1);
782 			if (ret != 0)
783 				return (ret);
784 		} else
785 			return (0);
786 	}
787 
788 	b = CHN_BUF_PARENT(c, c->bufhard);
789 
790 	minflush = threshold + sndbuf_xbytes(sndbuf_getready(b), b, bs);
791 
792 	syncdelay = chn_syncdelay;
793 
794 	if (syncdelay < 0 && (threshold > 0 || sndbuf_getready(bs) > 0))
795 		minflush += sndbuf_xbytes(sndbuf_getsize(b), b, bs);
796 
797 	/*
798 	 * Append (0-1000) millisecond trailing buffer (if needed)
799 	 * for slower / high latency hardwares (notably USB audio)
800 	 * to avoid audible truncation.
801 	 */
802 	if (syncdelay > 0)
803 		minflush += (sndbuf_getalign(bs) * sndbuf_getspd(bs) *
804 		    ((syncdelay > 1000) ? 1000 : syncdelay)) / 1000;
805 
806 	minflush -= minflush % sndbuf_getalign(bs);
807 
808 	if (minflush > 0) {
809 		threshold = min(minflush, sndbuf_getfree(bs));
810 		sndbuf_clear(bs, threshold);
811 		sndbuf_acquire(bs, NULL, threshold);
812 		minflush -= threshold;
813 	}
814 
815 	resid = sndbuf_getready(bs);
816 	residp = resid;
817 	blksz = sndbuf_getblksz(b);
818 	if (blksz < 1) {
819 		device_printf(c->dev,
820 		    "%s(): WARNING: blksz < 1 ! maxsize=%d [%d/%d/%d]\n",
821 		    __func__, sndbuf_getmaxsize(b), sndbuf_getsize(b),
822 		    sndbuf_getblksz(b), sndbuf_getblkcnt(b));
823 		if (sndbuf_getblkcnt(b) > 0)
824 			blksz = sndbuf_getsize(b) / sndbuf_getblkcnt(b);
825 		if (blksz < 1)
826 			blksz = 1;
827 	}
828 	count = sndbuf_xbytes(minflush + resid, bs, b) / blksz;
829 	hcount = count;
830 	ret = 0;
831 
832 	if (snd_verbose > 3)
833 		device_printf(c->dev, "%s(): [begin] timeout=%d count=%d "
834 		    "minflush=%d resid=%d\n", __func__, c->timeout, count,
835 		    minflush, resid);
836 
837 	cflag = c->flags & CHN_F_CLOSING;
838 	c->flags |= CHN_F_CLOSING;
839 	while (count > 0 && (resid > 0 || minflush > 0)) {
840 		ret = chn_sleep(c, c->timeout);
841     		if (ret == ERESTART || ret == EINTR) {
842 			c->flags |= CHN_F_ABORTING;
843 			break;
844 		} else if (ret == 0 || ret == EAGAIN) {
845 			resid = sndbuf_getready(bs);
846 			if (resid == residp) {
847 				--count;
848 				if (snd_verbose > 3)
849 					device_printf(c->dev,
850 					    "%s(): [stalled] timeout=%d "
851 					    "count=%d hcount=%d "
852 					    "resid=%d minflush=%d\n",
853 					    __func__, c->timeout, count,
854 					    hcount, resid, minflush);
855 			} else if (resid < residp && count < hcount) {
856 				++count;
857 				if (snd_verbose > 3)
858 					device_printf(c->dev,
859 					    "%s((): [resume] timeout=%d "
860 					    "count=%d hcount=%d "
861 					    "resid=%d minflush=%d\n",
862 					    __func__, c->timeout, count,
863 					    hcount, resid, minflush);
864 			}
865 			if (minflush > 0 && sndbuf_getfree(bs) > 0) {
866 				threshold = min(minflush,
867 				    sndbuf_getfree(bs));
868 				sndbuf_clear(bs, threshold);
869 				sndbuf_acquire(bs, NULL, threshold);
870 				resid = sndbuf_getready(bs);
871 				minflush -= threshold;
872 			}
873 			residp = resid;
874 		} else
875 			break;
876 	}
877 	c->flags &= ~CHN_F_CLOSING;
878 	c->flags |= cflag;
879 
880 	if (snd_verbose > 3)
881 		device_printf(c->dev,
882 		    "%s(): timeout=%d count=%d hcount=%d resid=%d residp=%d "
883 		    "minflush=%d ret=%d\n",
884 		    __func__, c->timeout, count, hcount, resid, residp,
885 		    minflush, ret);
886 
887     	return (0);
888 }
889 
890 /* called externally, handle locking */
891 int
892 chn_poll(struct pcm_channel *c, int ev, struct thread *td)
893 {
894 	struct snd_dbuf *bs = c->bufsoft;
895 	int ret;
896 
897 	CHN_LOCKASSERT(c);
898 
899     	if (!(c->flags & (CHN_F_MMAP | CHN_F_TRIGGERED))) {
900 		ret = chn_start(c, 1);
901 		if (ret != 0)
902 			return (0);
903 	}
904 
905 	ret = 0;
906 	if (chn_polltrigger(c)) {
907 		chn_pollreset(c);
908 		ret = ev;
909 	} else
910 		selrecord(td, sndbuf_getsel(bs));
911 
912 	return (ret);
913 }
914 
915 /*
916  * chn_abort terminates a running dma transfer.  it may sleep up to 200ms.
917  * it returns the number of bytes that have not been transferred.
918  *
919  * called from: dsp_close, dsp_ioctl, with channel locked
920  */
921 int
922 chn_abort(struct pcm_channel *c)
923 {
924     	int missing = 0;
925     	struct snd_dbuf *b = c->bufhard;
926     	struct snd_dbuf *bs = c->bufsoft;
927 
928 	CHN_LOCKASSERT(c);
929 	if (CHN_STOPPED(c))
930 		return 0;
931 	c->flags |= CHN_F_ABORTING;
932 
933 	c->flags &= ~CHN_F_TRIGGERED;
934 	/* kill the channel */
935 	chn_trigger(c, PCMTRIG_ABORT);
936 	sndbuf_setrun(b, 0);
937 	if (!(c->flags & CHN_F_VIRTUAL))
938 		chn_dmaupdate(c);
939     	missing = sndbuf_getready(bs);
940 
941 	c->flags &= ~CHN_F_ABORTING;
942 	return missing;
943 }
944 
945 /*
946  * this routine tries to flush the dma transfer. It is called
947  * on a close of a playback channel.
948  * first, if there is data in the buffer, but the dma has not yet
949  * begun, we need to start it.
950  * next, we wait for the play buffer to drain
951  * finally, we stop the dma.
952  *
953  * called from: dsp_close, not valid for record channels.
954  */
955 
956 int
957 chn_flush(struct pcm_channel *c)
958 {
959     	struct snd_dbuf *b = c->bufhard;
960 
961 	CHN_LOCKASSERT(c);
962 	KASSERT(c->direction == PCMDIR_PLAY, ("chn_flush on bad channel"));
963     	DEB(printf("chn_flush: c->flags 0x%08x\n", c->flags));
964 
965 	c->flags |= CHN_F_CLOSING;
966 	chn_sync(c, 0);
967 	c->flags &= ~CHN_F_TRIGGERED;
968 	/* kill the channel */
969 	chn_trigger(c, PCMTRIG_ABORT);
970 	sndbuf_setrun(b, 0);
971 
972     	c->flags &= ~CHN_F_CLOSING;
973     	return 0;
974 }
975 
976 int
977 snd_fmtvalid(uint32_t fmt, uint32_t *fmtlist)
978 {
979 	int i;
980 
981 	for (i = 0; fmtlist[i] != 0; i++) {
982 		if (fmt == fmtlist[i] ||
983 		    ((fmt & AFMT_PASSTHROUGH) &&
984 		    (AFMT_ENCODING(fmt) & fmtlist[i])))
985 			return (1);
986 	}
987 
988 	return (0);
989 }
990 
991 static const struct {
992 	char *name, *alias1, *alias2;
993 	uint32_t afmt;
994 } afmt_tab[] = {
995 	{  "alaw",  NULL, NULL, AFMT_A_LAW  },
996 	{ "mulaw",  NULL, NULL, AFMT_MU_LAW },
997 	{    "u8",   "8", NULL, AFMT_U8     },
998 	{    "s8",  NULL, NULL, AFMT_S8     },
999 #if BYTE_ORDER == LITTLE_ENDIAN
1000 	{ "s16le", "s16", "16", AFMT_S16_LE },
1001 	{ "s16be",  NULL, NULL, AFMT_S16_BE },
1002 #else
1003 	{ "s16le",  NULL, NULL, AFMT_S16_LE },
1004 	{ "s16be", "s16", "16", AFMT_S16_BE },
1005 #endif
1006 	{ "u16le",  NULL, NULL, AFMT_U16_LE },
1007 	{ "u16be",  NULL, NULL, AFMT_U16_BE },
1008 	{ "s24le",  NULL, NULL, AFMT_S24_LE },
1009 	{ "s24be",  NULL, NULL, AFMT_S24_BE },
1010 	{ "u24le",  NULL, NULL, AFMT_U24_LE },
1011 	{ "u24be",  NULL, NULL, AFMT_U24_BE },
1012 #if BYTE_ORDER == LITTLE_ENDIAN
1013 	{ "s32le", "s32", "32", AFMT_S32_LE },
1014 	{ "s32be",  NULL, NULL, AFMT_S32_BE },
1015 #else
1016 	{ "s32le",  NULL, NULL, AFMT_S32_LE },
1017 	{ "s32be", "s32", "32", AFMT_S32_BE },
1018 #endif
1019 	{ "u32le",  NULL, NULL, AFMT_U32_LE },
1020 	{ "u32be",  NULL, NULL, AFMT_U32_BE },
1021 	{   "ac3",  NULL, NULL, AFMT_AC3    },
1022 	{    NULL,  NULL, NULL, 0           }
1023 };
1024 
1025 uint32_t
1026 snd_str2afmt(const char *req)
1027 {
1028 	int ext;
1029 	int ch;
1030 	int i;
1031 	char b1[8];
1032 	char b2[8];
1033 
1034 	memset(b1, 0, sizeof(b1));
1035 	memset(b2, 0, sizeof(b2));
1036 
1037 	i = sscanf(req, "%5[^:]:%6s", b1, b2);
1038 
1039 	if (i == 1) {
1040 		if (strlen(req) != strlen(b1))
1041 			return (0);
1042 		strlcpy(b2, "2.0", sizeof(b2));
1043 	} else if (i == 2) {
1044 		if (strlen(req) != (strlen(b1) + 1 + strlen(b2)))
1045 			return (0);
1046 	} else
1047 		return (0);
1048 
1049 	i = sscanf(b2, "%d.%d", &ch, &ext);
1050 
1051 	if (i == 0) {
1052 		if (strcasecmp(b2, "mono") == 0) {
1053 			ch = 1;
1054 			ext = 0;
1055 		} else if (strcasecmp(b2, "stereo") == 0) {
1056 			ch = 2;
1057 			ext = 0;
1058 		} else if (strcasecmp(b2, "quad") == 0) {
1059 			ch = 4;
1060 			ext = 0;
1061 		} else
1062 			return (0);
1063 	} else if (i == 1) {
1064 		if (ch < 1 || ch > AFMT_CHANNEL_MAX)
1065 			return (0);
1066 		ext = 0;
1067 	} else if (i == 2) {
1068 		if (ext < 0 || ext > AFMT_EXTCHANNEL_MAX)
1069 			return (0);
1070 		if (ch < 1 || (ch + ext) > AFMT_CHANNEL_MAX)
1071 			return (0);
1072 	} else
1073 		return (0);
1074 
1075 	for (i = 0; afmt_tab[i].name != NULL; i++) {
1076 		if (strcasecmp(afmt_tab[i].name, b1) != 0) {
1077 			if (afmt_tab[i].alias1 == NULL)
1078 				continue;
1079 			if (strcasecmp(afmt_tab[i].alias1, b1) != 0) {
1080 				if (afmt_tab[i].alias2 == NULL)
1081 					continue;
1082 				if (strcasecmp(afmt_tab[i].alias2, b1) != 0)
1083 					continue;
1084 			}
1085 		}
1086 		/* found a match */
1087 		return (SND_FORMAT(afmt_tab[i].afmt, ch + ext, ext));
1088 	}
1089 	/* not a valid format */
1090 	return (0);
1091 }
1092 
1093 uint32_t
1094 snd_afmt2str(uint32_t afmt, char *buf, size_t len)
1095 {
1096 	uint32_t enc;
1097 	uint32_t ext;
1098 	uint32_t ch;
1099 	int i;
1100 
1101 	if (buf == NULL || len < AFMTSTR_LEN)
1102 		return (0);
1103 
1104 	memset(buf, 0, len);
1105 
1106 	enc = AFMT_ENCODING(afmt);
1107 	ch = AFMT_CHANNEL(afmt);
1108 	ext = AFMT_EXTCHANNEL(afmt);
1109 	/* check there is at least one channel */
1110 	if (ch <= ext)
1111 		return (0);
1112 	for (i = 0; afmt_tab[i].name != NULL; i++) {
1113 		if (enc != afmt_tab[i].afmt)
1114 			continue;
1115 		/* found a match */
1116 		snprintf(buf, len, "%s:%d.%d",
1117 		    afmt_tab[i].name, ch - ext, ext);
1118 		return (SND_FORMAT(enc, ch, ext));
1119 	}
1120 	return (0);
1121 }
1122 
1123 int
1124 chn_reset(struct pcm_channel *c, uint32_t fmt, uint32_t spd)
1125 {
1126 	int r;
1127 
1128 	CHN_LOCKASSERT(c);
1129 	c->feedcount = 0;
1130 	c->flags &= CHN_F_RESET;
1131 	c->interrupts = 0;
1132 	c->timeout = 1;
1133 	c->xruns = 0;
1134 
1135 	c->flags |= (pcm_getflags(c->dev) & SD_F_BITPERFECT) ?
1136 	    CHN_F_BITPERFECT : 0;
1137 
1138 	r = CHANNEL_RESET(c->methods, c->devinfo);
1139 	if (r == 0 && fmt != 0 && spd != 0) {
1140 		r = chn_setparam(c, fmt, spd);
1141 		fmt = 0;
1142 		spd = 0;
1143 	}
1144 	if (r == 0 && fmt != 0)
1145 		r = chn_setformat(c, fmt);
1146 	if (r == 0 && spd != 0)
1147 		r = chn_setspeed(c, spd);
1148 	if (r == 0)
1149 		r = chn_setlatency(c, chn_latency);
1150 	if (r == 0) {
1151 		chn_resetbuf(c);
1152 		r = CHANNEL_RESETDONE(c->methods, c->devinfo);
1153 	}
1154 	return r;
1155 }
1156 
1157 int
1158 chn_init(struct pcm_channel *c, void *devinfo, int dir, int direction)
1159 {
1160 	struct feeder_class *fc;
1161 	struct snd_dbuf *b, *bs;
1162 	int i, ret;
1163 
1164 	if (chn_timeout < CHN_TIMEOUT_MIN || chn_timeout > CHN_TIMEOUT_MAX)
1165 		chn_timeout = CHN_TIMEOUT;
1166 
1167 	chn_lockinit(c, dir);
1168 
1169 	b = NULL;
1170 	bs = NULL;
1171 	CHN_INIT(c, children);
1172 	CHN_INIT(c, children.busy);
1173 	c->devinfo = NULL;
1174 	c->feeder = NULL;
1175 	c->latency = -1;
1176 	c->timeout = 1;
1177 
1178 	ret = ENOMEM;
1179 	b = sndbuf_create(c->dev, c->name, "primary", c);
1180 	if (b == NULL)
1181 		goto out;
1182 	bs = sndbuf_create(c->dev, c->name, "secondary", c);
1183 	if (bs == NULL)
1184 		goto out;
1185 
1186 	CHN_LOCK(c);
1187 
1188 	ret = EINVAL;
1189 	fc = feeder_getclass(NULL);
1190 	if (fc == NULL)
1191 		goto out;
1192 	if (chn_addfeeder(c, fc, NULL))
1193 		goto out;
1194 
1195 	/*
1196 	 * XXX - sndbuf_setup() & sndbuf_resize() expect to be called
1197 	 *	 with the channel unlocked because they are also called
1198 	 *	 from driver methods that don't know about locking
1199 	 */
1200 	CHN_UNLOCK(c);
1201 	sndbuf_setup(bs, NULL, 0);
1202 	CHN_LOCK(c);
1203 	c->bufhard = b;
1204 	c->bufsoft = bs;
1205 	c->flags = 0;
1206 	c->feederflags = 0;
1207 	c->sm = NULL;
1208 	c->format = SND_FORMAT(AFMT_U8, 1, 0);
1209 	c->speed = DSP_DEFAULT_SPEED;
1210 
1211 	c->matrix = *feeder_matrix_id_map(SND_CHN_MATRIX_1_0);
1212 	c->matrix.id = SND_CHN_MATRIX_PCMCHANNEL;
1213 
1214 	for (i = 0; i < SND_CHN_T_MAX; i++) {
1215 		c->volume[SND_VOL_C_MASTER][i] = SND_VOL_0DB_MASTER;
1216 	}
1217 
1218 	c->volume[SND_VOL_C_MASTER][SND_CHN_T_VOL_0DB] = SND_VOL_0DB_MASTER;
1219 	c->volume[SND_VOL_C_PCM][SND_CHN_T_VOL_0DB] = chn_vol_0db_pcm;
1220 
1221 	chn_vpc_reset(c, SND_VOL_C_PCM, 1);
1222 
1223 	ret = ENODEV;
1224 	CHN_UNLOCK(c); /* XXX - Unlock for CHANNEL_INIT() malloc() call */
1225 	c->devinfo = CHANNEL_INIT(c->methods, devinfo, b, c, direction);
1226 	CHN_LOCK(c);
1227 	if (c->devinfo == NULL)
1228 		goto out;
1229 
1230 	ret = ENOMEM;
1231 	if ((sndbuf_getsize(b) == 0) && ((c->flags & CHN_F_VIRTUAL) == 0))
1232 		goto out;
1233 
1234 	ret = 0;
1235 	c->direction = direction;
1236 
1237 	sndbuf_setfmt(b, c->format);
1238 	sndbuf_setspd(b, c->speed);
1239 	sndbuf_setfmt(bs, c->format);
1240 	sndbuf_setspd(bs, c->speed);
1241 
1242 	/**
1243 	 * @todo Should this be moved somewhere else?  The primary buffer
1244 	 * 	 is allocated by the driver or via DMA map setup, and tmpbuf
1245 	 * 	 seems to only come into existence in sndbuf_resize().
1246 	 */
1247 	if (c->direction == PCMDIR_PLAY) {
1248 		bs->sl = sndbuf_getmaxsize(bs);
1249 		bs->shadbuf = malloc(bs->sl, M_DEVBUF, M_NOWAIT);
1250 		if (bs->shadbuf == NULL) {
1251 			ret = ENOMEM;
1252 			goto out;
1253 		}
1254 	}
1255 
1256 out:
1257 	CHN_UNLOCK(c);
1258 	if (ret) {
1259 		if (c->devinfo) {
1260 			if (CHANNEL_FREE(c->methods, c->devinfo))
1261 				sndbuf_free(b);
1262 		}
1263 		if (bs)
1264 			sndbuf_destroy(bs);
1265 		if (b)
1266 			sndbuf_destroy(b);
1267 		CHN_LOCK(c);
1268 		c->flags |= CHN_F_DEAD;
1269 		chn_lockdestroy(c);
1270 
1271 		return ret;
1272 	}
1273 
1274 	return 0;
1275 }
1276 
1277 int
1278 chn_kill(struct pcm_channel *c)
1279 {
1280     	struct snd_dbuf *b = c->bufhard;
1281     	struct snd_dbuf *bs = c->bufsoft;
1282 
1283 	if (CHN_STARTED(c)) {
1284 		CHN_LOCK(c);
1285 		chn_trigger(c, PCMTRIG_ABORT);
1286 		CHN_UNLOCK(c);
1287 	}
1288 	while (chn_removefeeder(c) == 0)
1289 		;
1290 	if (CHANNEL_FREE(c->methods, c->devinfo))
1291 		sndbuf_free(b);
1292 	sndbuf_destroy(bs);
1293 	sndbuf_destroy(b);
1294 	CHN_LOCK(c);
1295 	c->flags |= CHN_F_DEAD;
1296 	chn_lockdestroy(c);
1297 
1298 	return (0);
1299 }
1300 
1301 /* XXX Obsolete. Use *_matrix() variant instead. */
1302 int
1303 chn_setvolume(struct pcm_channel *c, int left, int right)
1304 {
1305 	int ret;
1306 
1307 	ret = chn_setvolume_matrix(c, SND_VOL_C_MASTER, SND_CHN_T_FL, left);
1308 	ret |= chn_setvolume_matrix(c, SND_VOL_C_MASTER, SND_CHN_T_FR,
1309 	    right) << 8;
1310 
1311 	return (ret);
1312 }
1313 
1314 int
1315 chn_setvolume_multi(struct pcm_channel *c, int vc, int left, int right,
1316     int center)
1317 {
1318 	int i, ret;
1319 
1320 	ret = 0;
1321 
1322 	for (i = 0; i < SND_CHN_T_MAX; i++) {
1323 		if ((1 << i) & SND_CHN_LEFT_MASK)
1324 			ret |= chn_setvolume_matrix(c, vc, i, left);
1325 		else if ((1 << i) & SND_CHN_RIGHT_MASK)
1326 			ret |= chn_setvolume_matrix(c, vc, i, right) << 8;
1327 		else
1328 			ret |= chn_setvolume_matrix(c, vc, i, center) << 16;
1329 	}
1330 
1331 	return (ret);
1332 }
1333 
1334 int
1335 chn_setvolume_matrix(struct pcm_channel *c, int vc, int vt, int val)
1336 {
1337 	int i;
1338 
1339 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1340 	    (vc == SND_VOL_C_MASTER || (vc & 1)) &&
1341 	    (vt == SND_CHN_T_VOL_0DB || (vt >= SND_CHN_T_BEGIN &&
1342 	    vt <= SND_CHN_T_END)) && (vt != SND_CHN_T_VOL_0DB ||
1343 	    (val >= SND_VOL_0DB_MIN && val <= SND_VOL_0DB_MAX)),
1344 	    ("%s(): invalid volume matrix c=%p vc=%d vt=%d val=%d",
1345 	    __func__, c, vc, vt, val));
1346 	CHN_LOCKASSERT(c);
1347 
1348 	if (val < 0)
1349 		val = 0;
1350 	if (val > 100)
1351 		val = 100;
1352 
1353 	c->volume[vc][vt] = val;
1354 
1355 	/*
1356 	 * Do relative calculation here and store it into class + 1
1357 	 * to ease the job of feeder_volume.
1358 	 */
1359 	if (vc == SND_VOL_C_MASTER) {
1360 		for (vc = SND_VOL_C_BEGIN; vc <= SND_VOL_C_END;
1361 		    vc += SND_VOL_C_STEP)
1362 			c->volume[SND_VOL_C_VAL(vc)][vt] =
1363 			    SND_VOL_CALC_VAL(c->volume, vc, vt);
1364 	} else if (vc & 1) {
1365 		if (vt == SND_CHN_T_VOL_0DB)
1366 			for (i = SND_CHN_T_BEGIN; i <= SND_CHN_T_END;
1367 			    i += SND_CHN_T_STEP) {
1368 				c->volume[SND_VOL_C_VAL(vc)][i] =
1369 				    SND_VOL_CALC_VAL(c->volume, vc, i);
1370 			}
1371 		else
1372 			c->volume[SND_VOL_C_VAL(vc)][vt] =
1373 			    SND_VOL_CALC_VAL(c->volume, vc, vt);
1374 	}
1375 
1376 	return (val);
1377 }
1378 
1379 int
1380 chn_getvolume_matrix(struct pcm_channel *c, int vc, int vt)
1381 {
1382 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1383 	    (vt == SND_CHN_T_VOL_0DB ||
1384 	    (vt >= SND_CHN_T_BEGIN && vt <= SND_CHN_T_END)),
1385 	    ("%s(): invalid volume matrix c=%p vc=%d vt=%d",
1386 	    __func__, c, vc, vt));
1387 	CHN_LOCKASSERT(c);
1388 
1389 	return (c->volume[vc][vt]);
1390 }
1391 
1392 struct pcmchan_matrix *
1393 chn_getmatrix(struct pcm_channel *c)
1394 {
1395 
1396 	KASSERT(c != NULL, ("%s(): NULL channel", __func__));
1397 	CHN_LOCKASSERT(c);
1398 
1399 	if (!(c->format & AFMT_CONVERTIBLE))
1400 		return (NULL);
1401 
1402 	return (&c->matrix);
1403 }
1404 
1405 int
1406 chn_setmatrix(struct pcm_channel *c, struct pcmchan_matrix *m)
1407 {
1408 
1409 	KASSERT(c != NULL && m != NULL,
1410 	    ("%s(): NULL channel or matrix", __func__));
1411 	CHN_LOCKASSERT(c);
1412 
1413 	if (!(c->format & AFMT_CONVERTIBLE))
1414 		return (EINVAL);
1415 
1416 	c->matrix = *m;
1417 	c->matrix.id = SND_CHN_MATRIX_PCMCHANNEL;
1418 
1419 	return (chn_setformat(c, SND_FORMAT(c->format, m->channels, m->ext)));
1420 }
1421 
1422 /*
1423  * XXX chn_oss_* exists for the sake of compatibility.
1424  */
1425 int
1426 chn_oss_getorder(struct pcm_channel *c, unsigned long long *map)
1427 {
1428 
1429 	KASSERT(c != NULL && map != NULL,
1430 	    ("%s(): NULL channel or map", __func__));
1431 	CHN_LOCKASSERT(c);
1432 
1433 	if (!(c->format & AFMT_CONVERTIBLE))
1434 		return (EINVAL);
1435 
1436 	return (feeder_matrix_oss_get_channel_order(&c->matrix, map));
1437 }
1438 
1439 int
1440 chn_oss_setorder(struct pcm_channel *c, unsigned long long *map)
1441 {
1442 	struct pcmchan_matrix m;
1443 	int ret;
1444 
1445 	KASSERT(c != NULL && map != NULL,
1446 	    ("%s(): NULL channel or map", __func__));
1447 	CHN_LOCKASSERT(c);
1448 
1449 	if (!(c->format & AFMT_CONVERTIBLE))
1450 		return (EINVAL);
1451 
1452 	m = c->matrix;
1453 	ret = feeder_matrix_oss_set_channel_order(&m, map);
1454 	if (ret != 0)
1455 		return (ret);
1456 
1457 	return (chn_setmatrix(c, &m));
1458 }
1459 
1460 #define SND_CHN_OSS_FRONT	(SND_CHN_T_MASK_FL | SND_CHN_T_MASK_FR)
1461 #define SND_CHN_OSS_SURR	(SND_CHN_T_MASK_SL | SND_CHN_T_MASK_SR)
1462 #define SND_CHN_OSS_CENTER_LFE	(SND_CHN_T_MASK_FC | SND_CHN_T_MASK_LF)
1463 #define SND_CHN_OSS_REAR	(SND_CHN_T_MASK_BL | SND_CHN_T_MASK_BR)
1464 
1465 int
1466 chn_oss_getmask(struct pcm_channel *c, uint32_t *retmask)
1467 {
1468 	struct pcmchan_matrix *m;
1469 	struct pcmchan_caps *caps;
1470 	uint32_t i, format;
1471 
1472 	KASSERT(c != NULL && retmask != NULL,
1473 	    ("%s(): NULL channel or retmask", __func__));
1474 	CHN_LOCKASSERT(c);
1475 
1476 	caps = chn_getcaps(c);
1477 	if (caps == NULL || caps->fmtlist == NULL)
1478 		return (ENODEV);
1479 
1480 	for (i = 0; caps->fmtlist[i] != 0; i++) {
1481 		format = caps->fmtlist[i];
1482 		if (!(format & AFMT_CONVERTIBLE)) {
1483 			*retmask |= DSP_BIND_SPDIF;
1484 			continue;
1485 		}
1486 		m = CHANNEL_GETMATRIX(c->methods, c->devinfo, format);
1487 		if (m == NULL)
1488 			continue;
1489 		if (m->mask & SND_CHN_OSS_FRONT)
1490 			*retmask |= DSP_BIND_FRONT;
1491 		if (m->mask & SND_CHN_OSS_SURR)
1492 			*retmask |= DSP_BIND_SURR;
1493 		if (m->mask & SND_CHN_OSS_CENTER_LFE)
1494 			*retmask |= DSP_BIND_CENTER_LFE;
1495 		if (m->mask & SND_CHN_OSS_REAR)
1496 			*retmask |= DSP_BIND_REAR;
1497 	}
1498 
1499 	/* report software-supported binding mask */
1500 	if (!CHN_BITPERFECT(c) && report_soft_matrix)
1501 		*retmask |= DSP_BIND_FRONT | DSP_BIND_SURR |
1502 		    DSP_BIND_CENTER_LFE | DSP_BIND_REAR;
1503 
1504 	return (0);
1505 }
1506 
1507 void
1508 chn_vpc_reset(struct pcm_channel *c, int vc, int force)
1509 {
1510 	int i;
1511 
1512 	KASSERT(c != NULL && vc >= SND_VOL_C_BEGIN && vc <= SND_VOL_C_END,
1513 	    ("%s(): invalid reset c=%p vc=%d", __func__, c, vc));
1514 	CHN_LOCKASSERT(c);
1515 
1516 	if (force == 0 && chn_vpc_autoreset == 0)
1517 		return;
1518 
1519 	for (i = SND_CHN_T_BEGIN; i <= SND_CHN_T_END; i += SND_CHN_T_STEP)
1520 		CHN_SETVOLUME(c, vc, i, c->volume[vc][SND_CHN_T_VOL_0DB]);
1521 }
1522 
1523 static u_int32_t
1524 round_pow2(u_int32_t v)
1525 {
1526 	u_int32_t ret;
1527 
1528 	if (v < 2)
1529 		v = 2;
1530 	ret = 0;
1531 	while (v >> ret)
1532 		ret++;
1533 	ret = 1 << (ret - 1);
1534 	while (ret < v)
1535 		ret <<= 1;
1536 	return ret;
1537 }
1538 
1539 static u_int32_t
1540 round_blksz(u_int32_t v, int round)
1541 {
1542 	u_int32_t ret, tmp;
1543 
1544 	if (round < 1)
1545 		round = 1;
1546 
1547 	ret = min(round_pow2(v), CHN_2NDBUFMAXSIZE >> 1);
1548 
1549 	if (ret > v && (ret >> 1) > 0 && (ret >> 1) >= ((v * 3) >> 2))
1550 		ret >>= 1;
1551 
1552 	tmp = ret - (ret % round);
1553 	while (tmp < 16 || tmp < round) {
1554 		ret <<= 1;
1555 		tmp = ret - (ret % round);
1556 	}
1557 
1558 	return ret;
1559 }
1560 
1561 /*
1562  * 4Front call it DSP Policy, while we call it "Latency Profile". The idea
1563  * is to keep 2nd buffer short so that it doesn't cause long queue during
1564  * buffer transfer.
1565  *
1566  *    Latency reference table for 48khz stereo 16bit: (PLAY)
1567  *
1568  *      +---------+------------+-----------+------------+
1569  *      | Latency | Blockcount | Blocksize | Buffersize |
1570  *      +---------+------------+-----------+------------+
1571  *      |     0   |       2    |   64      |    128     |
1572  *      +---------+------------+-----------+------------+
1573  *      |     1   |       4    |   128     |    512     |
1574  *      +---------+------------+-----------+------------+
1575  *      |     2   |       8    |   512     |    4096    |
1576  *      +---------+------------+-----------+------------+
1577  *      |     3   |      16    |   512     |    8192    |
1578  *      +---------+------------+-----------+------------+
1579  *      |     4   |      32    |   512     |    16384   |
1580  *      +---------+------------+-----------+------------+
1581  *      |     5   |      32    |   1024    |    32768   |
1582  *      +---------+------------+-----------+------------+
1583  *      |     6   |      16    |   2048    |    32768   |
1584  *      +---------+------------+-----------+------------+
1585  *      |     7   |       8    |   4096    |    32768   |
1586  *      +---------+------------+-----------+------------+
1587  *      |     8   |       4    |   8192    |    32768   |
1588  *      +---------+------------+-----------+------------+
1589  *      |     9   |       2    |   16384   |    32768   |
1590  *      +---------+------------+-----------+------------+
1591  *      |    10   |       2    |   32768   |    65536   |
1592  *      +---------+------------+-----------+------------+
1593  *
1594  * Recording need a different reference table. All we care is
1595  * gobbling up everything within reasonable buffering threshold.
1596  *
1597  *    Latency reference table for 48khz stereo 16bit: (REC)
1598  *
1599  *      +---------+------------+-----------+------------+
1600  *      | Latency | Blockcount | Blocksize | Buffersize |
1601  *      +---------+------------+-----------+------------+
1602  *      |     0   |     512    |   32      |    16384   |
1603  *      +---------+------------+-----------+------------+
1604  *      |     1   |     256    |   64      |    16384   |
1605  *      +---------+------------+-----------+------------+
1606  *      |     2   |     128    |   128     |    16384   |
1607  *      +---------+------------+-----------+------------+
1608  *      |     3   |      64    |   256     |    16384   |
1609  *      +---------+------------+-----------+------------+
1610  *      |     4   |      32    |   512     |    16384   |
1611  *      +---------+------------+-----------+------------+
1612  *      |     5   |      32    |   1024    |    32768   |
1613  *      +---------+------------+-----------+------------+
1614  *      |     6   |      16    |   2048    |    32768   |
1615  *      +---------+------------+-----------+------------+
1616  *      |     7   |       8    |   4096    |    32768   |
1617  *      +---------+------------+-----------+------------+
1618  *      |     8   |       4    |   8192    |    32768   |
1619  *      +---------+------------+-----------+------------+
1620  *      |     9   |       2    |   16384   |    32768   |
1621  *      +---------+------------+-----------+------------+
1622  *      |    10   |       2    |   32768   |    65536   |
1623  *      +---------+------------+-----------+------------+
1624  *
1625  * Calculations for other data rate are entirely based on these reference
1626  * tables. For normal operation, Latency 5 seems give the best, well
1627  * balanced performance for typical workload. Anything below 5 will
1628  * eat up CPU to keep up with increasing context switches because of
1629  * shorter buffer space and usually require the application to handle it
1630  * aggresively through possibly real time programming technique.
1631  *
1632  */
1633 #define CHN_LATENCY_PBLKCNT_REF				\
1634 	{{1, 2, 3, 4, 5, 5, 4, 3, 2, 1, 1},		\
1635 	{1, 2, 3, 4, 5, 5, 4, 3, 2, 1, 1}}
1636 #define CHN_LATENCY_PBUFSZ_REF				\
1637 	{{7, 9, 12, 13, 14, 15, 15, 15, 15, 15, 16},	\
1638 	{11, 12, 13, 14, 15, 16, 16, 16, 16, 16, 17}}
1639 
1640 #define CHN_LATENCY_RBLKCNT_REF				\
1641 	{{9, 8, 7, 6, 5, 5, 4, 3, 2, 1, 1},		\
1642 	{9, 8, 7, 6, 5, 5, 4, 3, 2, 1, 1}}
1643 #define CHN_LATENCY_RBUFSZ_REF				\
1644 	{{14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16},	\
1645 	{15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 17}}
1646 
1647 #define CHN_LATENCY_DATA_REF	192000 /* 48khz stereo 16bit ~ 48000 x 2 x 2 */
1648 
1649 static int
1650 chn_calclatency(int dir, int latency, int bps, u_int32_t datarate,
1651 				u_int32_t max, int *rblksz, int *rblkcnt)
1652 {
1653 	static int pblkcnts[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1654 	    CHN_LATENCY_PBLKCNT_REF;
1655 	static int  pbufszs[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1656 	    CHN_LATENCY_PBUFSZ_REF;
1657 	static int rblkcnts[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1658 	    CHN_LATENCY_RBLKCNT_REF;
1659 	static int  rbufszs[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1660 	    CHN_LATENCY_RBUFSZ_REF;
1661 	u_int32_t bufsz;
1662 	int lprofile, blksz, blkcnt;
1663 
1664 	if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX ||
1665 	    bps < 1 || datarate < 1 ||
1666 	    !(dir == PCMDIR_PLAY || dir == PCMDIR_REC)) {
1667 		if (rblksz != NULL)
1668 			*rblksz = CHN_2NDBUFMAXSIZE >> 1;
1669 		if (rblkcnt != NULL)
1670 			*rblkcnt = 2;
1671 		printf("%s(): FAILED dir=%d latency=%d bps=%d "
1672 		    "datarate=%u max=%u\n",
1673 		    __func__, dir, latency, bps, datarate, max);
1674 		return CHN_2NDBUFMAXSIZE;
1675 	}
1676 
1677 	lprofile = chn_latency_profile;
1678 
1679 	if (dir == PCMDIR_PLAY) {
1680 		blkcnt = pblkcnts[lprofile][latency];
1681 		bufsz = pbufszs[lprofile][latency];
1682 	} else {
1683 		blkcnt = rblkcnts[lprofile][latency];
1684 		bufsz = rbufszs[lprofile][latency];
1685 	}
1686 
1687 	bufsz = round_pow2(snd_xbytes(1 << bufsz, CHN_LATENCY_DATA_REF,
1688 	    datarate));
1689 	if (bufsz > max)
1690 		bufsz = max;
1691 	blksz = round_blksz(bufsz >> blkcnt, bps);
1692 
1693 	if (rblksz != NULL)
1694 		*rblksz = blksz;
1695 	if (rblkcnt != NULL)
1696 		*rblkcnt = 1 << blkcnt;
1697 
1698 	return blksz << blkcnt;
1699 }
1700 
1701 static int
1702 chn_resizebuf(struct pcm_channel *c, int latency,
1703 					int blkcnt, int blksz)
1704 {
1705 	struct snd_dbuf *b, *bs, *pb;
1706 	int sblksz, sblkcnt, hblksz, hblkcnt, limit = 0, nsblksz, nsblkcnt;
1707 	int ret;
1708 
1709 	CHN_LOCKASSERT(c);
1710 
1711 	if ((c->flags & (CHN_F_MMAP | CHN_F_TRIGGERED)) ||
1712 	    !(c->direction == PCMDIR_PLAY || c->direction == PCMDIR_REC))
1713 		return EINVAL;
1714 
1715 	if (latency == -1) {
1716 		c->latency = -1;
1717 		latency = chn_latency;
1718 	} else if (latency == -2) {
1719 		latency = c->latency;
1720 		if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX)
1721 			latency = chn_latency;
1722 	} else if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX)
1723 		return EINVAL;
1724 	else {
1725 		c->latency = latency;
1726 	}
1727 
1728 	bs = c->bufsoft;
1729 	b = c->bufhard;
1730 
1731 	if (!(blksz == 0 || blkcnt == -1) &&
1732 	    (blksz < 16 || blksz < sndbuf_getalign(bs) || blkcnt < 2 ||
1733 	    (blksz * blkcnt) > CHN_2NDBUFMAXSIZE))
1734 		return EINVAL;
1735 
1736 	chn_calclatency(c->direction, latency, sndbuf_getalign(bs),
1737 	    sndbuf_getalign(bs) * sndbuf_getspd(bs), CHN_2NDBUFMAXSIZE,
1738 	    &sblksz, &sblkcnt);
1739 
1740 	if (blksz == 0 || blkcnt == -1) {
1741 		if (blkcnt == -1)
1742 			c->flags &= ~CHN_F_HAS_SIZE;
1743 		if (c->flags & CHN_F_HAS_SIZE) {
1744 			blksz = sndbuf_getblksz(bs);
1745 			blkcnt = sndbuf_getblkcnt(bs);
1746 		}
1747 	} else
1748 		c->flags |= CHN_F_HAS_SIZE;
1749 
1750 	if (c->flags & CHN_F_HAS_SIZE) {
1751 		/*
1752 		 * The application has requested their own blksz/blkcnt.
1753 		 * Just obey with it, and let them toast alone. We can
1754 		 * clamp it to the nearest latency profile, but that would
1755 		 * defeat the purpose of having custom control. The least
1756 		 * we can do is round it to the nearest ^2 and align it.
1757 		 */
1758 		sblksz = round_blksz(blksz, sndbuf_getalign(bs));
1759 		sblkcnt = round_pow2(blkcnt);
1760 	}
1761 
1762 	if (c->parentchannel != NULL) {
1763 		pb = c->parentchannel->bufsoft;
1764 		CHN_UNLOCK(c);
1765 		CHN_LOCK(c->parentchannel);
1766 		chn_notify(c->parentchannel, CHN_N_BLOCKSIZE);
1767 		CHN_UNLOCK(c->parentchannel);
1768 		CHN_LOCK(c);
1769 		if (c->direction == PCMDIR_PLAY) {
1770 			limit = (pb != NULL) ?
1771 			    sndbuf_xbytes(sndbuf_getsize(pb), pb, bs) : 0;
1772 		} else {
1773 			limit = (pb != NULL) ?
1774 			    sndbuf_xbytes(sndbuf_getblksz(pb), pb, bs) * 2 : 0;
1775 		}
1776 	} else {
1777 		hblkcnt = 2;
1778 		if (c->flags & CHN_F_HAS_SIZE) {
1779 			hblksz = round_blksz(sndbuf_xbytes(sblksz, bs, b),
1780 			    sndbuf_getalign(b));
1781 			hblkcnt = round_pow2(sndbuf_getblkcnt(bs));
1782 		} else
1783 			chn_calclatency(c->direction, latency,
1784 			    sndbuf_getalign(b),
1785 			    sndbuf_getalign(b) * sndbuf_getspd(b),
1786 			    CHN_2NDBUFMAXSIZE, &hblksz, &hblkcnt);
1787 
1788 		if ((hblksz << 1) > sndbuf_getmaxsize(b))
1789 			hblksz = round_blksz(sndbuf_getmaxsize(b) >> 1,
1790 			    sndbuf_getalign(b));
1791 
1792 		while ((hblksz * hblkcnt) > sndbuf_getmaxsize(b)) {
1793 			if (hblkcnt < 4)
1794 				hblksz >>= 1;
1795 			else
1796 				hblkcnt >>= 1;
1797 		}
1798 
1799 		hblksz -= hblksz % sndbuf_getalign(b);
1800 
1801 #if 0
1802 		hblksz = sndbuf_getmaxsize(b) >> 1;
1803 		hblksz -= hblksz % sndbuf_getalign(b);
1804 		hblkcnt = 2;
1805 #endif
1806 
1807 		CHN_UNLOCK(c);
1808 		if (chn_usefrags == 0 ||
1809 		    CHANNEL_SETFRAGMENTS(c->methods, c->devinfo,
1810 		    hblksz, hblkcnt) != 0)
1811 			sndbuf_setblksz(b, CHANNEL_SETBLOCKSIZE(c->methods,
1812 			    c->devinfo, hblksz));
1813 		CHN_LOCK(c);
1814 
1815 		if (!CHN_EMPTY(c, children)) {
1816 			nsblksz = round_blksz(
1817 			    sndbuf_xbytes(sndbuf_getblksz(b), b, bs),
1818 			    sndbuf_getalign(bs));
1819 			nsblkcnt = sndbuf_getblkcnt(b);
1820 			if (c->direction == PCMDIR_PLAY) {
1821 				do {
1822 					nsblkcnt--;
1823 				} while (nsblkcnt >= 2 &&
1824 				    nsblksz * nsblkcnt >= sblksz * sblkcnt);
1825 				nsblkcnt++;
1826 			}
1827 			sblksz = nsblksz;
1828 			sblkcnt = nsblkcnt;
1829 			limit = 0;
1830 		} else
1831 			limit = sndbuf_xbytes(sndbuf_getblksz(b), b, bs) * 2;
1832 	}
1833 
1834 	if (limit > CHN_2NDBUFMAXSIZE)
1835 		limit = CHN_2NDBUFMAXSIZE;
1836 
1837 #if 0
1838 	while (limit > 0 && (sblksz * sblkcnt) > limit) {
1839 		if (sblkcnt < 4)
1840 			break;
1841 		sblkcnt >>= 1;
1842 	}
1843 #endif
1844 
1845 	while ((sblksz * sblkcnt) < limit)
1846 		sblkcnt <<= 1;
1847 
1848 	while ((sblksz * sblkcnt) > CHN_2NDBUFMAXSIZE) {
1849 		if (sblkcnt < 4)
1850 			sblksz >>= 1;
1851 		else
1852 			sblkcnt >>= 1;
1853 	}
1854 
1855 	sblksz -= sblksz % sndbuf_getalign(bs);
1856 
1857 	if (sndbuf_getblkcnt(bs) != sblkcnt || sndbuf_getblksz(bs) != sblksz ||
1858 	    sndbuf_getsize(bs) != (sblkcnt * sblksz)) {
1859 		ret = sndbuf_remalloc(bs, sblkcnt, sblksz);
1860 		if (ret != 0) {
1861 			device_printf(c->dev, "%s(): Failed: %d %d\n",
1862 			    __func__, sblkcnt, sblksz);
1863 			return ret;
1864 		}
1865 	}
1866 
1867 	/*
1868 	 * Interrupt timeout
1869 	 */
1870 	c->timeout = ((u_int64_t)hz * sndbuf_getsize(bs)) /
1871 	    ((u_int64_t)sndbuf_getspd(bs) * sndbuf_getalign(bs));
1872 	if (c->parentchannel != NULL)
1873 		c->timeout = min(c->timeout, c->parentchannel->timeout);
1874 	if (c->timeout < 1)
1875 		c->timeout = 1;
1876 
1877 	/*
1878 	 * OSSv4 docs: "By default OSS will set the low water level equal
1879 	 * to the fragment size which is optimal in most cases."
1880 	 */
1881 	c->lw = sndbuf_getblksz(bs);
1882 	chn_resetbuf(c);
1883 
1884 	if (snd_verbose > 3)
1885 		device_printf(c->dev, "%s(): %s (%s) timeout=%u "
1886 		    "b[%d/%d/%d] bs[%d/%d/%d] limit=%d\n",
1887 		    __func__, CHN_DIRSTR(c),
1888 		    (c->flags & CHN_F_VIRTUAL) ? "virtual" : "hardware",
1889 		    c->timeout,
1890 		    sndbuf_getsize(b), sndbuf_getblksz(b),
1891 		    sndbuf_getblkcnt(b),
1892 		    sndbuf_getsize(bs), sndbuf_getblksz(bs),
1893 		    sndbuf_getblkcnt(bs), limit);
1894 
1895 	return 0;
1896 }
1897 
1898 int
1899 chn_setlatency(struct pcm_channel *c, int latency)
1900 {
1901 	CHN_LOCKASSERT(c);
1902 	/* Destroy blksz/blkcnt, enforce latency profile. */
1903 	return chn_resizebuf(c, latency, -1, 0);
1904 }
1905 
1906 int
1907 chn_setblocksize(struct pcm_channel *c, int blkcnt, int blksz)
1908 {
1909 	CHN_LOCKASSERT(c);
1910 	/* Destroy latency profile, enforce blksz/blkcnt */
1911 	return chn_resizebuf(c, -1, blkcnt, blksz);
1912 }
1913 
1914 int
1915 chn_setparam(struct pcm_channel *c, uint32_t format, uint32_t speed)
1916 {
1917 	struct pcmchan_caps *caps;
1918 	uint32_t hwspeed, delta;
1919 	int ret;
1920 
1921 	CHN_LOCKASSERT(c);
1922 
1923 	if (speed < 1 || format == 0 || CHN_STARTED(c))
1924 		return (EINVAL);
1925 
1926 	c->format = format;
1927 	c->speed = speed;
1928 
1929 	caps = chn_getcaps(c);
1930 
1931 	hwspeed = speed;
1932 	RANGE(hwspeed, caps->minspeed, caps->maxspeed);
1933 
1934 	sndbuf_setspd(c->bufhard, CHANNEL_SETSPEED(c->methods, c->devinfo,
1935 	    hwspeed));
1936 	hwspeed = sndbuf_getspd(c->bufhard);
1937 
1938 	delta = (hwspeed > speed) ? (hwspeed - speed) : (speed - hwspeed);
1939 
1940 	if (delta <= feeder_rate_round)
1941 		c->speed = hwspeed;
1942 
1943 	ret = feeder_chain(c);
1944 
1945 	if (ret == 0)
1946 		ret = CHANNEL_SETFORMAT(c->methods, c->devinfo,
1947 		    sndbuf_getfmt(c->bufhard));
1948 
1949 	if (ret == 0)
1950 		ret = chn_resizebuf(c, -2, 0, 0);
1951 
1952 	return (ret);
1953 }
1954 
1955 int
1956 chn_setspeed(struct pcm_channel *c, uint32_t speed)
1957 {
1958 	uint32_t oldformat, oldspeed, format;
1959 	int ret;
1960 
1961 #if 0
1962 	/* XXX force 48k */
1963 	if (c->format & AFMT_PASSTHROUGH)
1964 		speed = AFMT_PASSTHROUGH_RATE;
1965 #endif
1966 
1967 	oldformat = c->format;
1968 	oldspeed = c->speed;
1969 	format = oldformat;
1970 
1971 	ret = chn_setparam(c, format, speed);
1972 	if (ret != 0) {
1973 		if (snd_verbose > 3)
1974 			device_printf(c->dev,
1975 			    "%s(): Setting speed %d failed, "
1976 			    "falling back to %d\n",
1977 			    __func__, speed, oldspeed);
1978 		chn_setparam(c, c->format, oldspeed);
1979 	}
1980 
1981 	return (ret);
1982 }
1983 
1984 int
1985 chn_setformat(struct pcm_channel *c, uint32_t format)
1986 {
1987 	uint32_t oldformat, oldspeed, speed;
1988 	int ret;
1989 
1990 	/* XXX force stereo */
1991 	if ((format & AFMT_PASSTHROUGH) && AFMT_CHANNEL(format) < 2) {
1992 		format = SND_FORMAT(format, AFMT_PASSTHROUGH_CHANNEL,
1993 		    AFMT_PASSTHROUGH_EXTCHANNEL);
1994 	}
1995 
1996 	oldformat = c->format;
1997 	oldspeed = c->speed;
1998 	speed = oldspeed;
1999 
2000 	ret = chn_setparam(c, format, speed);
2001 	if (ret != 0) {
2002 		if (snd_verbose > 3)
2003 			device_printf(c->dev,
2004 			    "%s(): Format change 0x%08x failed, "
2005 			    "falling back to 0x%08x\n",
2006 			    __func__, format, oldformat);
2007 		chn_setparam(c, oldformat, oldspeed);
2008 	}
2009 
2010 	return (ret);
2011 }
2012 
2013 void
2014 chn_syncstate(struct pcm_channel *c)
2015 {
2016 	struct snddev_info *d;
2017 	struct snd_mixer *m;
2018 
2019 	d = (c != NULL) ? c->parentsnddev : NULL;
2020 	m = (d != NULL && d->mixer_dev != NULL) ? d->mixer_dev->si_drv1 :
2021 	    NULL;
2022 
2023 	if (d == NULL || m == NULL)
2024 		return;
2025 
2026 	CHN_LOCKASSERT(c);
2027 
2028 	if (c->feederflags & (1 << FEEDER_VOLUME)) {
2029 		uint32_t parent;
2030 		int vol, pvol, left, right, center;
2031 
2032 		if (c->direction == PCMDIR_PLAY &&
2033 		    (d->flags & SD_F_SOFTPCMVOL)) {
2034 			/* CHN_UNLOCK(c); */
2035 			vol = mix_get(m, SOUND_MIXER_PCM);
2036 			parent = mix_getparent(m, SOUND_MIXER_PCM);
2037 			if (parent != SOUND_MIXER_NONE)
2038 				pvol = mix_get(m, parent);
2039 			else
2040 				pvol = 100 | (100 << 8);
2041 			/* CHN_LOCK(c); */
2042 		} else {
2043 			vol = 100 | (100 << 8);
2044 			pvol = vol;
2045 		}
2046 
2047 		if (vol == -1) {
2048 			device_printf(c->dev,
2049 			    "Soft PCM Volume: Failed to read pcm "
2050 			    "default value\n");
2051 			vol = 100 | (100 << 8);
2052 		}
2053 
2054 		if (pvol == -1) {
2055 			device_printf(c->dev,
2056 			    "Soft PCM Volume: Failed to read parent "
2057 			    "default value\n");
2058 			pvol = 100 | (100 << 8);
2059 		}
2060 
2061 		left = ((vol & 0x7f) * (pvol & 0x7f)) / 100;
2062 		right = (((vol >> 8) & 0x7f) * ((pvol >> 8) & 0x7f)) / 100;
2063 		center = (left + right) >> 1;
2064 
2065 		chn_setvolume_multi(c, SND_VOL_C_MASTER, left, right, center);
2066 	}
2067 
2068 	if (c->feederflags & (1 << FEEDER_EQ)) {
2069 		struct pcm_feeder *f;
2070 		int treble, bass, state;
2071 
2072 		/* CHN_UNLOCK(c); */
2073 		treble = mix_get(m, SOUND_MIXER_TREBLE);
2074 		bass = mix_get(m, SOUND_MIXER_BASS);
2075 		/* CHN_LOCK(c); */
2076 
2077 		if (treble == -1)
2078 			treble = 50;
2079 		else
2080 			treble = ((treble & 0x7f) +
2081 			    ((treble >> 8) & 0x7f)) >> 1;
2082 
2083 		if (bass == -1)
2084 			bass = 50;
2085 		else
2086 			bass = ((bass & 0x7f) + ((bass >> 8) & 0x7f)) >> 1;
2087 
2088 		f = chn_findfeeder(c, FEEDER_EQ);
2089 		if (f != NULL) {
2090 			if (FEEDER_SET(f, FEEDEQ_TREBLE, treble) != 0)
2091 				device_printf(c->dev,
2092 				    "EQ: Failed to set treble -- %d\n",
2093 				    treble);
2094 			if (FEEDER_SET(f, FEEDEQ_BASS, bass) != 0)
2095 				device_printf(c->dev,
2096 				    "EQ: Failed to set bass -- %d\n",
2097 				    bass);
2098 			if (FEEDER_SET(f, FEEDEQ_PREAMP, d->eqpreamp) != 0)
2099 				device_printf(c->dev,
2100 				    "EQ: Failed to set preamp -- %d\n",
2101 				    d->eqpreamp);
2102 			if (d->flags & SD_F_EQ_BYPASSED)
2103 				state = FEEDEQ_BYPASS;
2104 			else if (d->flags & SD_F_EQ_ENABLED)
2105 				state = FEEDEQ_ENABLE;
2106 			else
2107 				state = FEEDEQ_DISABLE;
2108 			if (FEEDER_SET(f, FEEDEQ_STATE, state) != 0)
2109 				device_printf(c->dev,
2110 				    "EQ: Failed to set state -- %d\n", state);
2111 		}
2112 	}
2113 }
2114 
2115 int
2116 chn_trigger(struct pcm_channel *c, int go)
2117 {
2118 #ifdef DEV_ISA
2119     	struct snd_dbuf *b = c->bufhard;
2120 #endif
2121 	struct snddev_info *d = c->parentsnddev;
2122 	int ret;
2123 
2124 	CHN_LOCKASSERT(c);
2125 #ifdef DEV_ISA
2126 	if (SND_DMA(b) && (go == PCMTRIG_EMLDMAWR || go == PCMTRIG_EMLDMARD))
2127 		sndbuf_dmabounce(b);
2128 #endif
2129 	if (!PCMTRIG_COMMON(go))
2130 		return (CHANNEL_TRIGGER(c->methods, c->devinfo, go));
2131 
2132 	if (go == c->trigger)
2133 		return (0);
2134 
2135 	ret = CHANNEL_TRIGGER(c->methods, c->devinfo, go);
2136 	if (ret != 0)
2137 		return (ret);
2138 
2139 	switch (go) {
2140 	case PCMTRIG_START:
2141 		if (snd_verbose > 3)
2142 			device_printf(c->dev,
2143 			    "%s() %s: calling go=0x%08x , "
2144 			    "prev=0x%08x\n", __func__, c->name, go,
2145 			    c->trigger);
2146 		if (c->trigger != PCMTRIG_START) {
2147 			c->trigger = go;
2148 			CHN_UNLOCK(c);
2149 			PCM_LOCK(d);
2150 			CHN_INSERT_HEAD(d, c, channels.pcm.busy);
2151 			PCM_UNLOCK(d);
2152 			CHN_LOCK(c);
2153 			chn_syncstate(c);
2154 		}
2155 		break;
2156 	case PCMTRIG_STOP:
2157 	case PCMTRIG_ABORT:
2158 		if (snd_verbose > 3)
2159 			device_printf(c->dev,
2160 			    "%s() %s: calling go=0x%08x , "
2161 			    "prev=0x%08x\n", __func__, c->name, go,
2162 			    c->trigger);
2163 		if (c->trigger == PCMTRIG_START) {
2164 			c->trigger = go;
2165 			CHN_UNLOCK(c);
2166 			PCM_LOCK(d);
2167 			CHN_REMOVE(d, c, channels.pcm.busy);
2168 			PCM_UNLOCK(d);
2169 			CHN_LOCK(c);
2170 		}
2171 		break;
2172 	default:
2173 		break;
2174 	}
2175 
2176 	return (0);
2177 }
2178 
2179 /**
2180  * @brief Queries sound driver for sample-aligned hardware buffer pointer index
2181  *
2182  * This function obtains the hardware pointer location, then aligns it to
2183  * the current bytes-per-sample value before returning.  (E.g., a channel
2184  * running in 16 bit stereo mode would require 4 bytes per sample, so a
2185  * hwptr value ranging from 32-35 would be returned as 32.)
2186  *
2187  * @param c	PCM channel context
2188  * @returns 	sample-aligned hardware buffer pointer index
2189  */
2190 int
2191 chn_getptr(struct pcm_channel *c)
2192 {
2193 	int hwptr;
2194 
2195 	CHN_LOCKASSERT(c);
2196 	hwptr = (CHN_STARTED(c)) ? CHANNEL_GETPTR(c->methods, c->devinfo) : 0;
2197 	return (hwptr - (hwptr % sndbuf_getalign(c->bufhard)));
2198 }
2199 
2200 struct pcmchan_caps *
2201 chn_getcaps(struct pcm_channel *c)
2202 {
2203 	CHN_LOCKASSERT(c);
2204 	return CHANNEL_GETCAPS(c->methods, c->devinfo);
2205 }
2206 
2207 u_int32_t
2208 chn_getformats(struct pcm_channel *c)
2209 {
2210 	u_int32_t *fmtlist, fmts;
2211 	int i;
2212 
2213 	fmtlist = chn_getcaps(c)->fmtlist;
2214 	fmts = 0;
2215 	for (i = 0; fmtlist[i]; i++)
2216 		fmts |= fmtlist[i];
2217 
2218 	/* report software-supported formats */
2219 	if (!CHN_BITPERFECT(c) && report_soft_formats)
2220 		fmts |= AFMT_CONVERTIBLE;
2221 
2222 	return (AFMT_ENCODING(fmts));
2223 }
2224 
2225 int
2226 chn_notify(struct pcm_channel *c, u_int32_t flags)
2227 {
2228 	struct pcm_channel *ch;
2229 	struct pcmchan_caps *caps;
2230 	uint32_t bestformat, bestspeed, besthwformat, *vchanformat, *vchanrate;
2231 	uint32_t vpflags;
2232 	int dirty, err, run, nrun;
2233 
2234 	CHN_LOCKASSERT(c);
2235 
2236 	if (CHN_EMPTY(c, children))
2237 		return (ENODEV);
2238 
2239 	err = 0;
2240 
2241 	/*
2242 	 * If the hwchan is running, we can't change its rate, format or
2243 	 * blocksize
2244 	 */
2245 	run = (CHN_STARTED(c)) ? 1 : 0;
2246 	if (run)
2247 		flags &= CHN_N_VOLUME | CHN_N_TRIGGER;
2248 
2249 	if (flags & CHN_N_RATE) {
2250 		/*
2251 		 * XXX I'll make good use of this someday.
2252 		 *     However this is currently being superseded by
2253 		 *     the availability of CHN_F_VCHAN_DYNAMIC.
2254 		 */
2255 	}
2256 
2257 	if (flags & CHN_N_FORMAT) {
2258 		/*
2259 		 * XXX I'll make good use of this someday.
2260 		 *     However this is currently being superseded by
2261 		 *     the availability of CHN_F_VCHAN_DYNAMIC.
2262 		 */
2263 	}
2264 
2265 	if (flags & CHN_N_VOLUME) {
2266 		/*
2267 		 * XXX I'll make good use of this someday, though
2268 		 *     soft volume control is currently pretty much
2269 		 *     integrated.
2270 		 */
2271 	}
2272 
2273 	if (flags & CHN_N_BLOCKSIZE) {
2274 		/*
2275 		 * Set to default latency profile
2276 		 */
2277 		chn_setlatency(c, chn_latency);
2278 	}
2279 
2280 	if ((flags & CHN_N_TRIGGER) && !(c->flags & CHN_F_VCHAN_DYNAMIC)) {
2281 		nrun = CHN_EMPTY(c, children.busy) ? 0 : 1;
2282 		if (nrun && !run)
2283 			err = chn_start(c, 1);
2284 		if (!nrun && run)
2285 			chn_abort(c);
2286 		flags &= ~CHN_N_TRIGGER;
2287 	}
2288 
2289 	if (flags & CHN_N_TRIGGER) {
2290 		if (c->direction == PCMDIR_PLAY) {
2291 			vchanformat = &c->parentsnddev->pvchanformat;
2292 			vchanrate = &c->parentsnddev->pvchanrate;
2293 		} else {
2294 			vchanformat = &c->parentsnddev->rvchanformat;
2295 			vchanrate = &c->parentsnddev->rvchanrate;
2296 		}
2297 
2298 		/* Dynamic Virtual Channel */
2299 		if (!(c->flags & CHN_F_VCHAN_ADAPTIVE)) {
2300 			bestformat = *vchanformat;
2301 			bestspeed = *vchanrate;
2302 		} else {
2303 			bestformat = 0;
2304 			bestspeed = 0;
2305 		}
2306 
2307 		besthwformat = 0;
2308 		nrun = 0;
2309 		caps = chn_getcaps(c);
2310 		dirty = 0;
2311 		vpflags = 0;
2312 
2313 		CHN_FOREACH(ch, c, children.busy) {
2314 			CHN_LOCK(ch);
2315 			if ((ch->format & AFMT_PASSTHROUGH) &&
2316 			    snd_fmtvalid(ch->format, caps->fmtlist)) {
2317 				bestformat = ch->format;
2318 				bestspeed = ch->speed;
2319 				CHN_UNLOCK(ch);
2320 				vpflags = CHN_F_PASSTHROUGH;
2321 				nrun++;
2322 				break;
2323 			}
2324 			if ((ch->flags & CHN_F_EXCLUSIVE) && vpflags == 0) {
2325 				if (c->flags & CHN_F_VCHAN_ADAPTIVE) {
2326 					bestspeed = ch->speed;
2327 					RANGE(bestspeed, caps->minspeed,
2328 					    caps->maxspeed);
2329 					besthwformat = snd_fmtbest(ch->format,
2330 					    caps->fmtlist);
2331 					if (besthwformat != 0)
2332 						bestformat = besthwformat;
2333 				}
2334 				CHN_UNLOCK(ch);
2335 				vpflags = CHN_F_EXCLUSIVE;
2336 				nrun++;
2337 				continue;
2338 			}
2339 			if (!(c->flags & CHN_F_VCHAN_ADAPTIVE) ||
2340 			    vpflags != 0) {
2341 				CHN_UNLOCK(ch);
2342 				nrun++;
2343 				continue;
2344 			}
2345 			if (ch->speed > bestspeed) {
2346 				bestspeed = ch->speed;
2347 				RANGE(bestspeed, caps->minspeed,
2348 				    caps->maxspeed);
2349 			}
2350 			besthwformat = snd_fmtbest(ch->format, caps->fmtlist);
2351 			if (!(besthwformat & AFMT_VCHAN)) {
2352 				CHN_UNLOCK(ch);
2353 				nrun++;
2354 				continue;
2355 			}
2356 			if (AFMT_CHANNEL(besthwformat) >
2357 			    AFMT_CHANNEL(bestformat))
2358 				bestformat = besthwformat;
2359 			else if (AFMT_CHANNEL(besthwformat) ==
2360 			    AFMT_CHANNEL(bestformat) &&
2361 			    AFMT_BIT(besthwformat) > AFMT_BIT(bestformat))
2362 				bestformat = besthwformat;
2363 			CHN_UNLOCK(ch);
2364 			nrun++;
2365 		}
2366 
2367 		if (bestformat == 0)
2368 			bestformat = c->format;
2369 		if (bestspeed == 0)
2370 			bestspeed = c->speed;
2371 
2372 		if (bestformat != c->format || bestspeed != c->speed)
2373 			dirty = 1;
2374 
2375 		c->flags &= ~(CHN_F_PASSTHROUGH | CHN_F_EXCLUSIVE);
2376 		c->flags |= vpflags;
2377 
2378 		if (nrun && !run) {
2379 			if (dirty) {
2380 				bestspeed = CHANNEL_SETSPEED(c->methods,
2381 				    c->devinfo, bestspeed);
2382 				err = chn_reset(c, bestformat, bestspeed);
2383 			}
2384 			if (err == 0 && dirty) {
2385 				CHN_FOREACH(ch, c, children.busy) {
2386 					CHN_LOCK(ch);
2387 					if (VCHAN_SYNC_REQUIRED(ch))
2388 						vchan_sync(ch);
2389 					CHN_UNLOCK(ch);
2390 				}
2391 			}
2392 			if (err == 0) {
2393 				if (dirty)
2394 					c->flags |= CHN_F_DIRTY;
2395 				err = chn_start(c, 1);
2396 			}
2397 		}
2398 
2399 		if (nrun && run && dirty) {
2400 			chn_abort(c);
2401 			bestspeed = CHANNEL_SETSPEED(c->methods, c->devinfo,
2402 			    bestspeed);
2403 			err = chn_reset(c, bestformat, bestspeed);
2404 			if (err == 0) {
2405 				CHN_FOREACH(ch, c, children.busy) {
2406 					CHN_LOCK(ch);
2407 					if (VCHAN_SYNC_REQUIRED(ch))
2408 						vchan_sync(ch);
2409 					CHN_UNLOCK(ch);
2410 				}
2411 			}
2412 			if (err == 0) {
2413 				c->flags |= CHN_F_DIRTY;
2414 				err = chn_start(c, 1);
2415 			}
2416 		}
2417 
2418 		if (err == 0 && !(bestformat & AFMT_PASSTHROUGH) &&
2419 		    (bestformat & AFMT_VCHAN)) {
2420 			*vchanformat = bestformat;
2421 			*vchanrate = bestspeed;
2422 		}
2423 
2424 		if (!nrun && run) {
2425 			c->flags &= ~(CHN_F_PASSTHROUGH | CHN_F_EXCLUSIVE);
2426 			bestformat = *vchanformat;
2427 			bestspeed = *vchanrate;
2428 			chn_abort(c);
2429 			if (c->format != bestformat || c->speed != bestspeed)
2430 				chn_reset(c, bestformat, bestspeed);
2431 		}
2432 	}
2433 
2434 	return (err);
2435 }
2436 
2437 /**
2438  * @brief Fetch array of supported discrete sample rates
2439  *
2440  * Wrapper for CHANNEL_GETRATES.  Please see channel_if.m:getrates() for
2441  * detailed information.
2442  *
2443  * @note If the operation isn't supported, this function will just return 0
2444  *       (no rates in the array), and *rates will be set to NULL.  Callers
2445  *       should examine rates @b only if this function returns non-zero.
2446  *
2447  * @param c	pcm channel to examine
2448  * @param rates	pointer to array of integers; rate table will be recorded here
2449  *
2450  * @return number of rates in the array pointed to be @c rates
2451  */
2452 int
2453 chn_getrates(struct pcm_channel *c, int **rates)
2454 {
2455 	KASSERT(rates != NULL, ("rates is null"));
2456 	CHN_LOCKASSERT(c);
2457 	return CHANNEL_GETRATES(c->methods, c->devinfo, rates);
2458 }
2459 
2460 /**
2461  * @brief Remove channel from a sync group, if there is one.
2462  *
2463  * This function is initially intended for the following conditions:
2464  *   - Starting a syncgroup (@c SNDCTL_DSP_SYNCSTART ioctl)
2465  *   - Closing a device.  (A channel can't be destroyed if it's still in use.)
2466  *
2467  * @note Before calling this function, the syncgroup list mutex must be
2468  * held.  (Consider pcm_channel::sm protected by the SG list mutex
2469  * whether @c c is locked or not.)
2470  *
2471  * @param c	channel device to be started or closed
2472  * @returns	If this channel was the only member of a group, the group ID
2473  * 		is returned to the caller so that the caller can release it
2474  * 		via free_unr() after giving up the syncgroup lock.  Else it
2475  * 		returns 0.
2476  */
2477 int
2478 chn_syncdestroy(struct pcm_channel *c)
2479 {
2480 	struct pcmchan_syncmember *sm;
2481 	struct pcmchan_syncgroup *sg;
2482 	int sg_id;
2483 
2484 	sg_id = 0;
2485 
2486 	PCM_SG_LOCKASSERT(MA_OWNED);
2487 
2488 	if (c->sm != NULL) {
2489 		sm = c->sm;
2490 		sg = sm->parent;
2491 		c->sm = NULL;
2492 
2493 		KASSERT(sg != NULL, ("syncmember has null parent"));
2494 
2495 		SLIST_REMOVE(&sg->members, sm, pcmchan_syncmember, link);
2496 		free(sm, M_DEVBUF);
2497 
2498 		if (SLIST_EMPTY(&sg->members)) {
2499 			SLIST_REMOVE(&snd_pcm_syncgroups, sg, pcmchan_syncgroup, link);
2500 			sg_id = sg->id;
2501 			free(sg, M_DEVBUF);
2502 		}
2503 	}
2504 
2505 	return sg_id;
2506 }
2507 
2508 #ifdef OSSV4_EXPERIMENT
2509 int
2510 chn_getpeaks(struct pcm_channel *c, int *lpeak, int *rpeak)
2511 {
2512 	CHN_LOCKASSERT(c);
2513 	return CHANNEL_GETPEAKS(c->methods, c->devinfo, lpeak, rpeak);
2514 }
2515 #endif
2516