xref: /freebsd/sys/dev/sound/pcm/channel.c (revision 347dd0539f3a75fdf2128dd4620ca99e96f311e9)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 #ifdef HAVE_KERNEL_OPTION_HEADERS
33 #include "opt_snd.h"
34 #endif
35 
36 #include <dev/sound/pcm/sound.h>
37 #include <dev/sound/pcm/vchan.h>
38 
39 #include "feeder_if.h"
40 
41 int report_soft_formats = 1;
42 SYSCTL_INT(_hw_snd, OID_AUTO, report_soft_formats, CTLFLAG_RW,
43 	&report_soft_formats, 0, "report software-emulated formats");
44 
45 int report_soft_matrix = 1;
46 SYSCTL_INT(_hw_snd, OID_AUTO, report_soft_matrix, CTLFLAG_RW,
47 	&report_soft_matrix, 0, "report software-emulated channel matrixing");
48 
49 int chn_latency = CHN_LATENCY_DEFAULT;
50 
51 static int
52 sysctl_hw_snd_latency(SYSCTL_HANDLER_ARGS)
53 {
54 	int err, val;
55 
56 	val = chn_latency;
57 	err = sysctl_handle_int(oidp, &val, 0, req);
58 	if (err != 0 || req->newptr == NULL)
59 		return err;
60 	if (val < CHN_LATENCY_MIN || val > CHN_LATENCY_MAX)
61 		err = EINVAL;
62 	else
63 		chn_latency = val;
64 
65 	return err;
66 }
67 SYSCTL_PROC(_hw_snd, OID_AUTO, latency,
68     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
69     sysctl_hw_snd_latency, "I",
70     "buffering latency (0=low ... 10=high)");
71 
72 int chn_latency_profile = CHN_LATENCY_PROFILE_DEFAULT;
73 
74 static int
75 sysctl_hw_snd_latency_profile(SYSCTL_HANDLER_ARGS)
76 {
77 	int err, val;
78 
79 	val = chn_latency_profile;
80 	err = sysctl_handle_int(oidp, &val, 0, req);
81 	if (err != 0 || req->newptr == NULL)
82 		return err;
83 	if (val < CHN_LATENCY_PROFILE_MIN || val > CHN_LATENCY_PROFILE_MAX)
84 		err = EINVAL;
85 	else
86 		chn_latency_profile = val;
87 
88 	return err;
89 }
90 SYSCTL_PROC(_hw_snd, OID_AUTO, latency_profile,
91     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
92     sysctl_hw_snd_latency_profile, "I",
93     "buffering latency profile (0=aggressive 1=safe)");
94 
95 static int chn_timeout = CHN_TIMEOUT;
96 
97 static int
98 sysctl_hw_snd_timeout(SYSCTL_HANDLER_ARGS)
99 {
100 	int err, val;
101 
102 	val = chn_timeout;
103 	err = sysctl_handle_int(oidp, &val, 0, req);
104 	if (err != 0 || req->newptr == NULL)
105 		return err;
106 	if (val < CHN_TIMEOUT_MIN || val > CHN_TIMEOUT_MAX)
107 		err = EINVAL;
108 	else
109 		chn_timeout = val;
110 
111 	return err;
112 }
113 SYSCTL_PROC(_hw_snd, OID_AUTO, timeout,
114     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, sizeof(int),
115     sysctl_hw_snd_timeout, "I",
116     "interrupt timeout (1 - 10) seconds");
117 
118 static int chn_vpc_autoreset = 1;
119 SYSCTL_INT(_hw_snd, OID_AUTO, vpc_autoreset, CTLFLAG_RWTUN,
120 	&chn_vpc_autoreset, 0, "automatically reset channels volume to 0db");
121 
122 static int chn_vol_0db_pcm = SND_VOL_0DB_PCM;
123 
124 static void
125 chn_vpc_proc(int reset, int db)
126 {
127 	struct snddev_info *d;
128 	struct pcm_channel *c;
129 	int i;
130 
131 	for (i = 0; pcm_devclass != NULL &&
132 	    i < devclass_get_maxunit(pcm_devclass); i++) {
133 		d = devclass_get_softc(pcm_devclass, i);
134 		if (!PCM_REGISTERED(d))
135 			continue;
136 		PCM_LOCK(d);
137 		PCM_WAIT(d);
138 		PCM_ACQUIRE(d);
139 		CHN_FOREACH(c, d, channels.pcm) {
140 			CHN_LOCK(c);
141 			CHN_SETVOLUME(c, SND_VOL_C_PCM, SND_CHN_T_VOL_0DB, db);
142 			if (reset != 0)
143 				chn_vpc_reset(c, SND_VOL_C_PCM, 1);
144 			CHN_UNLOCK(c);
145 		}
146 		PCM_RELEASE(d);
147 		PCM_UNLOCK(d);
148 	}
149 }
150 
151 static int
152 sysctl_hw_snd_vpc_0db(SYSCTL_HANDLER_ARGS)
153 {
154 	int err, val;
155 
156 	val = chn_vol_0db_pcm;
157 	err = sysctl_handle_int(oidp, &val, 0, req);
158 	if (err != 0 || req->newptr == NULL)
159 		return (err);
160 	if (val < SND_VOL_0DB_MIN || val > SND_VOL_0DB_MAX)
161 		return (EINVAL);
162 
163 	chn_vol_0db_pcm = val;
164 	chn_vpc_proc(0, val);
165 
166 	return (0);
167 }
168 SYSCTL_PROC(_hw_snd, OID_AUTO, vpc_0db,
169     CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_NEEDGIANT, 0, sizeof(int),
170     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,
189     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 0, sizeof(int),
190     sysctl_hw_snd_vpc_reset, "I",
191     "reset volume on all channels");
192 
193 static int chn_usefrags = 0;
194 static int chn_syncdelay = -1;
195 
196 SYSCTL_INT(_hw_snd, OID_AUTO, usefrags, CTLFLAG_RWTUN,
197 	&chn_usefrags, 0, "prefer setfragments() over setblocksize()");
198 SYSCTL_INT(_hw_snd, OID_AUTO, syncdelay, CTLFLAG_RWTUN,
199 	&chn_syncdelay, 0,
200 	"append (0-1000) millisecond trailing buffer delay on each sync");
201 
202 /**
203  * @brief Channel sync group lock
204  *
205  * Clients should acquire this lock @b without holding any channel locks
206  * before touching syncgroups or the main syncgroup list.
207  */
208 struct mtx snd_pcm_syncgroups_mtx;
209 MTX_SYSINIT(pcm_syncgroup, &snd_pcm_syncgroups_mtx, "PCM channel sync group lock", MTX_DEF);
210 /**
211  * @brief syncgroups' master list
212  *
213  * Each time a channel syncgroup is created, it's added to this list.  This
214  * list should only be accessed with @sa snd_pcm_syncgroups_mtx held.
215  *
216  * See SNDCTL_DSP_SYNCGROUP for more information.
217  */
218 struct pcm_synclist snd_pcm_syncgroups = SLIST_HEAD_INITIALIZER(snd_pcm_syncgroups);
219 
220 static void
221 chn_lockinit(struct pcm_channel *c, int dir)
222 {
223 	switch (dir) {
224 	case PCMDIR_PLAY:
225 		c->lock = snd_mtxcreate(c->name, "pcm play channel");
226 		cv_init(&c->intr_cv, "pcmwr");
227 		break;
228 	case PCMDIR_PLAY_VIRTUAL:
229 		c->lock = snd_mtxcreate(c->name, "pcm virtual play channel");
230 		cv_init(&c->intr_cv, "pcmwrv");
231 		break;
232 	case PCMDIR_REC:
233 		c->lock = snd_mtxcreate(c->name, "pcm record channel");
234 		cv_init(&c->intr_cv, "pcmrd");
235 		break;
236 	case PCMDIR_REC_VIRTUAL:
237 		c->lock = snd_mtxcreate(c->name, "pcm virtual record channel");
238 		cv_init(&c->intr_cv, "pcmrdv");
239 		break;
240 	default:
241 		panic("%s(): Invalid direction=%d", __func__, dir);
242 		break;
243 	}
244 
245 	cv_init(&c->cv, "pcmchn");
246 }
247 
248 static void
249 chn_lockdestroy(struct pcm_channel *c)
250 {
251 	CHN_LOCKASSERT(c);
252 
253 	CHN_BROADCAST(&c->cv);
254 	CHN_BROADCAST(&c->intr_cv);
255 
256 	cv_destroy(&c->cv);
257 	cv_destroy(&c->intr_cv);
258 
259 	snd_mtxfree(c->lock);
260 }
261 
262 /**
263  * @brief Determine channel is ready for I/O
264  *
265  * @retval 1 = ready for I/O
266  * @retval 0 = not ready for I/O
267  */
268 static int
269 chn_polltrigger(struct pcm_channel *c)
270 {
271 	struct snd_dbuf *bs = c->bufsoft;
272 	u_int delta;
273 
274 	CHN_LOCKASSERT(c);
275 
276 	if (c->flags & CHN_F_MMAP) {
277 		if (sndbuf_getprevtotal(bs) < c->lw)
278 			delta = c->lw;
279 		else
280 			delta = sndbuf_gettotal(bs) - sndbuf_getprevtotal(bs);
281 	} else {
282 		if (c->direction == PCMDIR_PLAY)
283 			delta = sndbuf_getfree(bs);
284 		else
285 			delta = sndbuf_getready(bs);
286 	}
287 
288 	return ((delta < c->lw) ? 0 : 1);
289 }
290 
291 static void
292 chn_pollreset(struct pcm_channel *c)
293 {
294 
295 	CHN_LOCKASSERT(c);
296 	sndbuf_updateprevtotal(c->bufsoft);
297 }
298 
299 static void
300 chn_wakeup(struct pcm_channel *c)
301 {
302 	struct snd_dbuf *bs;
303 	struct pcm_channel *ch;
304 
305 	CHN_LOCKASSERT(c);
306 
307 	bs = c->bufsoft;
308 
309 	if (CHN_EMPTY(c, children.busy)) {
310 		if (SEL_WAITING(sndbuf_getsel(bs)) && chn_polltrigger(c))
311 			selwakeuppri(sndbuf_getsel(bs), PRIBIO);
312 		CHN_BROADCAST(&c->intr_cv);
313 	} else {
314 		CHN_FOREACH(ch, c, children.busy) {
315 			CHN_LOCK(ch);
316 			chn_wakeup(ch);
317 			CHN_UNLOCK(ch);
318 		}
319 	}
320 }
321 
322 static int
323 chn_sleep(struct pcm_channel *c, int timeout)
324 {
325 	int ret;
326 
327 	CHN_LOCKASSERT(c);
328 
329 	if (c->flags & CHN_F_DEAD)
330 		return (EINVAL);
331 
332 	ret = cv_timedwait_sig(&c->intr_cv, c->lock, timeout);
333 
334 	return ((c->flags & CHN_F_DEAD) ? EINVAL : ret);
335 }
336 
337 /*
338  * chn_dmaupdate() tracks the status of a dma transfer,
339  * updating pointers.
340  */
341 
342 static unsigned int
343 chn_dmaupdate(struct pcm_channel *c)
344 {
345 	struct snd_dbuf *b = c->bufhard;
346 	unsigned int delta, old, hwptr, amt;
347 
348 	KASSERT(sndbuf_getsize(b) > 0, ("bufsize == 0"));
349 	CHN_LOCKASSERT(c);
350 
351 	old = sndbuf_gethwptr(b);
352 	hwptr = chn_getptr(c);
353 	delta = (sndbuf_getsize(b) + hwptr - old) % sndbuf_getsize(b);
354 	sndbuf_sethwptr(b, hwptr);
355 
356 	if (c->direction == PCMDIR_PLAY) {
357 		amt = min(delta, sndbuf_getready(b));
358 		amt -= amt % sndbuf_getalign(b);
359 		if (amt > 0)
360 			sndbuf_dispose(b, NULL, amt);
361 	} else {
362 		amt = min(delta, sndbuf_getfree(b));
363 		amt -= amt % sndbuf_getalign(b);
364 		if (amt > 0)
365 		       sndbuf_acquire(b, NULL, amt);
366 	}
367 	if (snd_verbose > 3 && CHN_STARTED(c) && delta == 0) {
368 		device_printf(c->dev, "WARNING: %s DMA completion "
369 			"too fast/slow ! hwptr=%u, old=%u "
370 			"delta=%u amt=%u ready=%u free=%u\n",
371 			CHN_DIRSTR(c), hwptr, old, delta, amt,
372 			sndbuf_getready(b), sndbuf_getfree(b));
373 	}
374 
375 	return delta;
376 }
377 
378 static void
379 chn_wrfeed(struct pcm_channel *c)
380 {
381     	struct snd_dbuf *b = c->bufhard;
382     	struct snd_dbuf *bs = c->bufsoft;
383 	unsigned int amt, want, wasfree;
384 
385 	CHN_LOCKASSERT(c);
386 
387 	if ((c->flags & CHN_F_MMAP) && !(c->flags & CHN_F_CLOSING))
388 		sndbuf_acquire(bs, NULL, sndbuf_getfree(bs));
389 
390 	wasfree = sndbuf_getfree(b);
391 	want = min(sndbuf_getsize(b),
392 	    imax(0, sndbuf_xbytes(sndbuf_getsize(bs), bs, b) -
393 	     sndbuf_getready(b)));
394 	amt = min(wasfree, want);
395 	if (amt > 0)
396 		sndbuf_feed(bs, b, c, c->feeder, amt);
397 
398 	/*
399 	 * Possible xruns. There should be no empty space left in buffer.
400 	 */
401 	if (sndbuf_getready(b) < want)
402 		c->xruns++;
403 
404 	if (sndbuf_getfree(b) < wasfree)
405 		chn_wakeup(c);
406 }
407 
408 #if 0
409 static void
410 chn_wrupdate(struct pcm_channel *c)
411 {
412 
413 	CHN_LOCKASSERT(c);
414 	KASSERT(c->direction == PCMDIR_PLAY, ("%s(): bad channel", __func__));
415 
416 	if ((c->flags & (CHN_F_MMAP | CHN_F_VIRTUAL)) || CHN_STOPPED(c))
417 		return;
418 	chn_dmaupdate(c);
419 	chn_wrfeed(c);
420 	/* tell the driver we've updated the primary buffer */
421 	chn_trigger(c, PCMTRIG_EMLDMAWR);
422 }
423 #endif
424 
425 static void
426 chn_wrintr(struct pcm_channel *c)
427 {
428 
429 	CHN_LOCKASSERT(c);
430 	/* update pointers in primary buffer */
431 	chn_dmaupdate(c);
432 	/* ...and feed from secondary to primary */
433 	chn_wrfeed(c);
434 	/* tell the driver we've updated the primary buffer */
435 	chn_trigger(c, PCMTRIG_EMLDMAWR);
436 }
437 
438 /*
439  * user write routine - uiomove data into secondary buffer, trigger if necessary
440  * if blocking, sleep, rinse and repeat.
441  *
442  * called externally, so must handle locking
443  */
444 
445 int
446 chn_write(struct pcm_channel *c, struct uio *buf)
447 {
448 	struct snd_dbuf *bs = c->bufsoft;
449 	void *off;
450 	int ret, timeout, sz, t, p;
451 
452 	CHN_LOCKASSERT(c);
453 
454 	ret = 0;
455 	timeout = chn_timeout * hz;
456 
457 	while (ret == 0 && buf->uio_resid > 0) {
458 		sz = min(buf->uio_resid, sndbuf_getfree(bs));
459 		if (sz > 0) {
460 			/*
461 			 * The following assumes that the free space in
462 			 * the buffer can never be less around the
463 			 * unlock-uiomove-lock sequence.
464 			 */
465 			while (ret == 0 && sz > 0) {
466 				p = sndbuf_getfreeptr(bs);
467 				t = min(sz, sndbuf_getsize(bs) - p);
468 				off = sndbuf_getbufofs(bs, p);
469 				CHN_UNLOCK(c);
470 				ret = uiomove(off, t, buf);
471 				CHN_LOCK(c);
472 				sz -= t;
473 				sndbuf_acquire(bs, NULL, t);
474 			}
475 			ret = 0;
476 			if (CHN_STOPPED(c) && !(c->flags & CHN_F_NOTRIGGER)) {
477 				ret = chn_start(c, 0);
478 				if (ret != 0)
479 					c->flags |= CHN_F_DEAD;
480 			}
481 		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER)) {
482 			/**
483 			 * @todo Evaluate whether EAGAIN is truly desirable.
484 			 * 	 4Front drivers behave like this, but I'm
485 			 * 	 not sure if it at all violates the "write
486 			 * 	 should be allowed to block" model.
487 			 *
488 			 * 	 The idea is that, while set with CHN_F_NOTRIGGER,
489 			 * 	 a channel isn't playing, *but* without this we
490 			 * 	 end up with "interrupt timeout / channel dead".
491 			 */
492 			ret = EAGAIN;
493 		} else {
494    			ret = chn_sleep(c, timeout);
495 			if (ret == EAGAIN) {
496 				ret = EINVAL;
497 				c->flags |= CHN_F_DEAD;
498 				device_printf(c->dev, "%s(): %s: "
499 				    "play interrupt timeout, channel dead\n",
500 				    __func__, c->name);
501 			} else if (ret == ERESTART || ret == EINTR)
502 				c->flags |= CHN_F_ABORTING;
503 		}
504 	}
505 
506 	return (ret);
507 }
508 
509 /*
510  * Feed new data from the read buffer. Can be called in the bottom half.
511  */
512 static void
513 chn_rdfeed(struct pcm_channel *c)
514 {
515     	struct snd_dbuf *b = c->bufhard;
516     	struct snd_dbuf *bs = c->bufsoft;
517 	unsigned int amt;
518 
519 	CHN_LOCKASSERT(c);
520 
521 	if (c->flags & CHN_F_MMAP)
522 		sndbuf_dispose(bs, NULL, sndbuf_getready(bs));
523 
524 	amt = sndbuf_getfree(bs);
525 	if (amt > 0)
526 		sndbuf_feed(b, bs, c, c->feeder, amt);
527 
528 	amt = sndbuf_getready(b);
529 	if (amt > 0) {
530 		c->xruns++;
531 		sndbuf_dispose(b, NULL, amt);
532 	}
533 
534 	if (sndbuf_getready(bs) > 0)
535 		chn_wakeup(c);
536 }
537 
538 #if 0
539 static void
540 chn_rdupdate(struct pcm_channel *c)
541 {
542 
543 	CHN_LOCKASSERT(c);
544 	KASSERT(c->direction == PCMDIR_REC, ("chn_rdupdate on bad channel"));
545 
546 	if ((c->flags & (CHN_F_MMAP | CHN_F_VIRTUAL)) || CHN_STOPPED(c))
547 		return;
548 	chn_trigger(c, PCMTRIG_EMLDMARD);
549 	chn_dmaupdate(c);
550 	chn_rdfeed(c);
551 }
552 #endif
553 
554 /* read interrupt routine. Must be called with interrupts blocked. */
555 static void
556 chn_rdintr(struct pcm_channel *c)
557 {
558 
559 	CHN_LOCKASSERT(c);
560 	/* tell the driver to update the primary buffer if non-dma */
561 	chn_trigger(c, PCMTRIG_EMLDMARD);
562 	/* update pointers in primary buffer */
563 	chn_dmaupdate(c);
564 	/* ...and feed from primary to secondary */
565 	chn_rdfeed(c);
566 }
567 
568 /*
569  * user read routine - trigger if necessary, uiomove data from secondary buffer
570  * if blocking, sleep, rinse and repeat.
571  *
572  * called externally, so must handle locking
573  */
574 
575 int
576 chn_read(struct pcm_channel *c, struct uio *buf)
577 {
578 	struct snd_dbuf *bs = c->bufsoft;
579 	void *off;
580 	int ret, timeout, sz, t, p;
581 
582 	CHN_LOCKASSERT(c);
583 
584 	if (CHN_STOPPED(c) && !(c->flags & CHN_F_NOTRIGGER)) {
585 		ret = chn_start(c, 0);
586 		if (ret != 0) {
587 			c->flags |= CHN_F_DEAD;
588 			return (ret);
589 		}
590 	}
591 
592 	ret = 0;
593 	timeout = chn_timeout * hz;
594 
595 	while (ret == 0 && buf->uio_resid > 0) {
596 		sz = min(buf->uio_resid, sndbuf_getready(bs));
597 		if (sz > 0) {
598 			/*
599 			 * The following assumes that the free space in
600 			 * the buffer can never be less around the
601 			 * unlock-uiomove-lock sequence.
602 			 */
603 			while (ret == 0 && sz > 0) {
604 				p = sndbuf_getreadyptr(bs);
605 				t = min(sz, sndbuf_getsize(bs) - p);
606 				off = sndbuf_getbufofs(bs, p);
607 				CHN_UNLOCK(c);
608 				ret = uiomove(off, t, buf);
609 				CHN_LOCK(c);
610 				sz -= t;
611 				sndbuf_dispose(bs, NULL, t);
612 			}
613 			ret = 0;
614 		} else if (c->flags & (CHN_F_NBIO | CHN_F_NOTRIGGER))
615 			ret = EAGAIN;
616 		else {
617    			ret = chn_sleep(c, timeout);
618 			if (ret == EAGAIN) {
619 				ret = EINVAL;
620 				c->flags |= CHN_F_DEAD;
621 				device_printf(c->dev, "%s(): %s: "
622 				    "record interrupt timeout, channel dead\n",
623 				    __func__, c->name);
624 			} else if (ret == ERESTART || ret == EINTR)
625 				c->flags |= CHN_F_ABORTING;
626 		}
627 	}
628 
629 	return (ret);
630 }
631 
632 void
633 chn_intr_locked(struct pcm_channel *c)
634 {
635 
636 	CHN_LOCKASSERT(c);
637 
638 	c->interrupts++;
639 
640 	if (c->direction == PCMDIR_PLAY)
641 		chn_wrintr(c);
642 	else
643 		chn_rdintr(c);
644 }
645 
646 void
647 chn_intr(struct pcm_channel *c)
648 {
649 
650 	if (CHN_LOCKOWNED(c)) {
651 		chn_intr_locked(c);
652 		return;
653 	}
654 
655 	CHN_LOCK(c);
656 	chn_intr_locked(c);
657 	CHN_UNLOCK(c);
658 }
659 
660 u_int32_t
661 chn_start(struct pcm_channel *c, int force)
662 {
663 	u_int32_t i, j;
664 	struct snd_dbuf *b = c->bufhard;
665 	struct snd_dbuf *bs = c->bufsoft;
666 	int err;
667 
668 	CHN_LOCKASSERT(c);
669 	/* if we're running, or if we're prevented from triggering, bail */
670 	if (CHN_STARTED(c) || ((c->flags & CHN_F_NOTRIGGER) && !force))
671 		return (EINVAL);
672 
673 	err = 0;
674 
675 	if (force) {
676 		i = 1;
677 		j = 0;
678 	} else {
679 		if (c->direction == PCMDIR_REC) {
680 			i = sndbuf_getfree(bs);
681 			j = (i > 0) ? 1 : sndbuf_getready(b);
682 		} else {
683 			if (sndbuf_getfree(bs) == 0) {
684 				i = 1;
685 				j = 0;
686 			} else {
687 				struct snd_dbuf *pb;
688 
689 				pb = CHN_BUF_PARENT(c, b);
690 				i = sndbuf_xbytes(sndbuf_getready(bs), bs, pb);
691 				j = sndbuf_getalign(pb);
692 			}
693 		}
694 		if (snd_verbose > 3 && CHN_EMPTY(c, children))
695 			device_printf(c->dev, "%s(): %s (%s) threshold "
696 			    "i=%d j=%d\n", __func__, CHN_DIRSTR(c),
697 			    (c->flags & CHN_F_VIRTUAL) ? "virtual" :
698 			    "hardware", i, j);
699 	}
700 
701 	if (i >= j) {
702 		c->flags |= CHN_F_TRIGGERED;
703 		sndbuf_setrun(b, 1);
704 		if (c->flags & CHN_F_CLOSING)
705 			c->feedcount = 2;
706 		else {
707 			c->feedcount = 0;
708 			c->interrupts = 0;
709 			c->xruns = 0;
710 		}
711 		if (c->parentchannel == NULL) {
712 			if (c->direction == PCMDIR_PLAY)
713 				sndbuf_fillsilence_rl(b,
714 				    sndbuf_xbytes(sndbuf_getsize(bs), bs, b));
715 			if (snd_verbose > 3)
716 				device_printf(c->dev,
717 				    "%s(): %s starting! (%s/%s) "
718 				    "(ready=%d force=%d i=%d j=%d "
719 				    "intrtimeout=%u latency=%dms)\n",
720 				    __func__,
721 				    (c->flags & CHN_F_HAS_VCHAN) ?
722 				    "VCHAN PARENT" : "HW", CHN_DIRSTR(c),
723 				    (c->flags & CHN_F_CLOSING) ? "closing" :
724 				    "running",
725 				    sndbuf_getready(b),
726 				    force, i, j, c->timeout,
727 				    (sndbuf_getsize(b) * 1000) /
728 				    (sndbuf_getalign(b) * sndbuf_getspd(b)));
729 		}
730 		err = chn_trigger(c, PCMTRIG_START);
731 	}
732 
733 	return (err);
734 }
735 
736 void
737 chn_resetbuf(struct pcm_channel *c)
738 {
739 	struct snd_dbuf *b = c->bufhard;
740 	struct snd_dbuf *bs = c->bufsoft;
741 
742 	c->blocks = 0;
743 	sndbuf_reset(b);
744 	sndbuf_reset(bs);
745 }
746 
747 /*
748  * chn_sync waits until the space in the given channel goes above
749  * a threshold. The threshold is checked against fl or rl respectively.
750  * Assume that the condition can become true, do not check here...
751  */
752 int
753 chn_sync(struct pcm_channel *c, int threshold)
754 {
755     	struct snd_dbuf *b, *bs;
756 	int ret, count, hcount, minflush, resid, residp, syncdelay, blksz;
757 	u_int32_t cflag;
758 
759 	CHN_LOCKASSERT(c);
760 
761 	if (c->direction != PCMDIR_PLAY)
762 		return (EINVAL);
763 
764 	bs = c->bufsoft;
765 
766 	if ((c->flags & (CHN_F_DEAD | CHN_F_ABORTING)) ||
767 	    (threshold < 1 && sndbuf_getready(bs) < 1))
768 		return (0);
769 
770 	/* if we haven't yet started and nothing is buffered, else start*/
771 	if (CHN_STOPPED(c)) {
772 		if (threshold > 0 || sndbuf_getready(bs) > 0) {
773 			ret = chn_start(c, 1);
774 			if (ret != 0)
775 				return (ret);
776 		} else
777 			return (0);
778 	}
779 
780 	b = CHN_BUF_PARENT(c, c->bufhard);
781 
782 	minflush = threshold + sndbuf_xbytes(sndbuf_getready(b), b, bs);
783 
784 	syncdelay = chn_syncdelay;
785 
786 	if (syncdelay < 0 && (threshold > 0 || sndbuf_getready(bs) > 0))
787 		minflush += sndbuf_xbytes(sndbuf_getsize(b), b, bs);
788 
789 	/*
790 	 * Append (0-1000) millisecond trailing buffer (if needed)
791 	 * for slower / high latency hardwares (notably USB audio)
792 	 * to avoid audible truncation.
793 	 */
794 	if (syncdelay > 0)
795 		minflush += (sndbuf_getalign(bs) * sndbuf_getspd(bs) *
796 		    ((syncdelay > 1000) ? 1000 : syncdelay)) / 1000;
797 
798 	minflush -= minflush % sndbuf_getalign(bs);
799 
800 	if (minflush > 0) {
801 		threshold = min(minflush, sndbuf_getfree(bs));
802 		sndbuf_clear(bs, threshold);
803 		sndbuf_acquire(bs, NULL, threshold);
804 		minflush -= threshold;
805 	}
806 
807 	resid = sndbuf_getready(bs);
808 	residp = resid;
809 	blksz = sndbuf_getblksz(b);
810 	if (blksz < 1) {
811 		device_printf(c->dev,
812 		    "%s(): WARNING: blksz < 1 ! maxsize=%d [%d/%d/%d]\n",
813 		    __func__, sndbuf_getmaxsize(b), sndbuf_getsize(b),
814 		    sndbuf_getblksz(b), sndbuf_getblkcnt(b));
815 		if (sndbuf_getblkcnt(b) > 0)
816 			blksz = sndbuf_getsize(b) / sndbuf_getblkcnt(b);
817 		if (blksz < 1)
818 			blksz = 1;
819 	}
820 	count = sndbuf_xbytes(minflush + resid, bs, b) / blksz;
821 	hcount = count;
822 	ret = 0;
823 
824 	if (snd_verbose > 3)
825 		device_printf(c->dev, "%s(): [begin] timeout=%d count=%d "
826 		    "minflush=%d resid=%d\n", __func__, c->timeout, count,
827 		    minflush, resid);
828 
829 	cflag = c->flags & CHN_F_CLOSING;
830 	c->flags |= CHN_F_CLOSING;
831 	while (count > 0 && (resid > 0 || minflush > 0)) {
832 		ret = chn_sleep(c, c->timeout);
833     		if (ret == ERESTART || ret == EINTR) {
834 			c->flags |= CHN_F_ABORTING;
835 			break;
836 		} else if (ret == 0 || ret == EAGAIN) {
837 			resid = sndbuf_getready(bs);
838 			if (resid == residp) {
839 				--count;
840 				if (snd_verbose > 3)
841 					device_printf(c->dev,
842 					    "%s(): [stalled] timeout=%d "
843 					    "count=%d hcount=%d "
844 					    "resid=%d minflush=%d\n",
845 					    __func__, c->timeout, count,
846 					    hcount, resid, minflush);
847 			} else if (resid < residp && count < hcount) {
848 				++count;
849 				if (snd_verbose > 3)
850 					device_printf(c->dev,
851 					    "%s((): [resume] timeout=%d "
852 					    "count=%d hcount=%d "
853 					    "resid=%d minflush=%d\n",
854 					    __func__, c->timeout, count,
855 					    hcount, resid, minflush);
856 			}
857 			if (minflush > 0 && sndbuf_getfree(bs) > 0) {
858 				threshold = min(minflush,
859 				    sndbuf_getfree(bs));
860 				sndbuf_clear(bs, threshold);
861 				sndbuf_acquire(bs, NULL, threshold);
862 				resid = sndbuf_getready(bs);
863 				minflush -= threshold;
864 			}
865 			residp = resid;
866 		} else
867 			break;
868 	}
869 	c->flags &= ~CHN_F_CLOSING;
870 	c->flags |= cflag;
871 
872 	if (snd_verbose > 3)
873 		device_printf(c->dev,
874 		    "%s(): timeout=%d count=%d hcount=%d resid=%d residp=%d "
875 		    "minflush=%d ret=%d\n",
876 		    __func__, c->timeout, count, hcount, resid, residp,
877 		    minflush, ret);
878 
879     	return (0);
880 }
881 
882 /* called externally, handle locking */
883 int
884 chn_poll(struct pcm_channel *c, int ev, struct thread *td)
885 {
886 	struct snd_dbuf *bs = c->bufsoft;
887 	int ret;
888 
889 	CHN_LOCKASSERT(c);
890 
891     	if (!(c->flags & (CHN_F_MMAP | CHN_F_TRIGGERED))) {
892 		ret = chn_start(c, 1);
893 		if (ret != 0)
894 			return (0);
895 	}
896 
897 	ret = 0;
898 	if (chn_polltrigger(c)) {
899 		chn_pollreset(c);
900 		ret = ev;
901 	} else
902 		selrecord(td, sndbuf_getsel(bs));
903 
904 	return (ret);
905 }
906 
907 /*
908  * chn_abort terminates a running dma transfer.  it may sleep up to 200ms.
909  * it returns the number of bytes that have not been transferred.
910  *
911  * called from: dsp_close, dsp_ioctl, with channel locked
912  */
913 int
914 chn_abort(struct pcm_channel *c)
915 {
916     	int missing = 0;
917     	struct snd_dbuf *b = c->bufhard;
918     	struct snd_dbuf *bs = c->bufsoft;
919 
920 	CHN_LOCKASSERT(c);
921 	if (CHN_STOPPED(c))
922 		return 0;
923 	c->flags |= CHN_F_ABORTING;
924 
925 	c->flags &= ~CHN_F_TRIGGERED;
926 	/* kill the channel */
927 	chn_trigger(c, PCMTRIG_ABORT);
928 	sndbuf_setrun(b, 0);
929 	if (!(c->flags & CHN_F_VIRTUAL))
930 		chn_dmaupdate(c);
931     	missing = sndbuf_getready(bs);
932 
933 	c->flags &= ~CHN_F_ABORTING;
934 	return missing;
935 }
936 
937 /*
938  * this routine tries to flush the dma transfer. It is called
939  * on a close of a playback channel.
940  * first, if there is data in the buffer, but the dma has not yet
941  * begun, we need to start it.
942  * next, we wait for the play buffer to drain
943  * finally, we stop the dma.
944  *
945  * called from: dsp_close, not valid for record channels.
946  */
947 
948 int
949 chn_flush(struct pcm_channel *c)
950 {
951     	struct snd_dbuf *b = c->bufhard;
952 
953 	CHN_LOCKASSERT(c);
954 	KASSERT(c->direction == PCMDIR_PLAY, ("chn_flush on bad channel"));
955     	DEB(printf("chn_flush: c->flags 0x%08x\n", c->flags));
956 
957 	c->flags |= CHN_F_CLOSING;
958 	chn_sync(c, 0);
959 	c->flags &= ~CHN_F_TRIGGERED;
960 	/* kill the channel */
961 	chn_trigger(c, PCMTRIG_ABORT);
962 	sndbuf_setrun(b, 0);
963 
964     	c->flags &= ~CHN_F_CLOSING;
965     	return 0;
966 }
967 
968 int
969 snd_fmtvalid(uint32_t fmt, uint32_t *fmtlist)
970 {
971 	int i;
972 
973 	for (i = 0; fmtlist[i] != 0; i++) {
974 		if (fmt == fmtlist[i] ||
975 		    ((fmt & AFMT_PASSTHROUGH) &&
976 		    (AFMT_ENCODING(fmt) & fmtlist[i])))
977 			return (1);
978 	}
979 
980 	return (0);
981 }
982 
983 static const struct {
984 	char *name, *alias1, *alias2;
985 	uint32_t afmt;
986 } afmt_tab[] = {
987 	{  "alaw",  NULL, NULL, AFMT_A_LAW  },
988 	{ "mulaw",  NULL, NULL, AFMT_MU_LAW },
989 	{    "u8",   "8", NULL, AFMT_U8     },
990 	{    "s8",  NULL, NULL, AFMT_S8     },
991 #if BYTE_ORDER == LITTLE_ENDIAN
992 	{ "s16le", "s16", "16", AFMT_S16_LE },
993 	{ "s16be",  NULL, NULL, AFMT_S16_BE },
994 #else
995 	{ "s16le",  NULL, NULL, AFMT_S16_LE },
996 	{ "s16be", "s16", "16", AFMT_S16_BE },
997 #endif
998 	{ "u16le",  NULL, NULL, AFMT_U16_LE },
999 	{ "u16be",  NULL, NULL, AFMT_U16_BE },
1000 	{ "s24le",  NULL, NULL, AFMT_S24_LE },
1001 	{ "s24be",  NULL, NULL, AFMT_S24_BE },
1002 	{ "u24le",  NULL, NULL, AFMT_U24_LE },
1003 	{ "u24be",  NULL, NULL, AFMT_U24_BE },
1004 #if BYTE_ORDER == LITTLE_ENDIAN
1005 	{ "s32le", "s32", "32", AFMT_S32_LE },
1006 	{ "s32be",  NULL, NULL, AFMT_S32_BE },
1007 #else
1008 	{ "s32le",  NULL, NULL, AFMT_S32_LE },
1009 	{ "s32be", "s32", "32", AFMT_S32_BE },
1010 #endif
1011 	{ "u32le",  NULL, NULL, AFMT_U32_LE },
1012 	{ "u32be",  NULL, NULL, AFMT_U32_BE },
1013 	{   "ac3",  NULL, NULL, AFMT_AC3    },
1014 	{    NULL,  NULL, NULL, 0           }
1015 };
1016 
1017 uint32_t
1018 snd_str2afmt(const char *req)
1019 {
1020 	int ext;
1021 	int ch;
1022 	int i;
1023 	char b1[8];
1024 	char b2[8];
1025 
1026 	memset(b1, 0, sizeof(b1));
1027 	memset(b2, 0, sizeof(b2));
1028 
1029 	i = sscanf(req, "%5[^:]:%6s", b1, b2);
1030 
1031 	if (i == 1) {
1032 		if (strlen(req) != strlen(b1))
1033 			return (0);
1034 		strlcpy(b2, "2.0", sizeof(b2));
1035 	} else if (i == 2) {
1036 		if (strlen(req) != (strlen(b1) + 1 + strlen(b2)))
1037 			return (0);
1038 	} else
1039 		return (0);
1040 
1041 	i = sscanf(b2, "%d.%d", &ch, &ext);
1042 
1043 	if (i == 0) {
1044 		if (strcasecmp(b2, "mono") == 0) {
1045 			ch = 1;
1046 			ext = 0;
1047 		} else if (strcasecmp(b2, "stereo") == 0) {
1048 			ch = 2;
1049 			ext = 0;
1050 		} else if (strcasecmp(b2, "quad") == 0) {
1051 			ch = 4;
1052 			ext = 0;
1053 		} else
1054 			return (0);
1055 	} else if (i == 1) {
1056 		if (ch < 1 || ch > AFMT_CHANNEL_MAX)
1057 			return (0);
1058 		ext = 0;
1059 	} else if (i == 2) {
1060 		if (ext < 0 || ext > AFMT_EXTCHANNEL_MAX)
1061 			return (0);
1062 		if (ch < 1 || (ch + ext) > AFMT_CHANNEL_MAX)
1063 			return (0);
1064 	} else
1065 		return (0);
1066 
1067 	for (i = 0; afmt_tab[i].name != NULL; i++) {
1068 		if (strcasecmp(afmt_tab[i].name, b1) != 0) {
1069 			if (afmt_tab[i].alias1 == NULL)
1070 				continue;
1071 			if (strcasecmp(afmt_tab[i].alias1, b1) != 0) {
1072 				if (afmt_tab[i].alias2 == NULL)
1073 					continue;
1074 				if (strcasecmp(afmt_tab[i].alias2, b1) != 0)
1075 					continue;
1076 			}
1077 		}
1078 		/* found a match */
1079 		return (SND_FORMAT(afmt_tab[i].afmt, ch + ext, ext));
1080 	}
1081 	/* not a valid format */
1082 	return (0);
1083 }
1084 
1085 uint32_t
1086 snd_afmt2str(uint32_t afmt, char *buf, size_t len)
1087 {
1088 	uint32_t enc;
1089 	uint32_t ext;
1090 	uint32_t ch;
1091 	int i;
1092 
1093 	if (buf == NULL || len < AFMTSTR_LEN)
1094 		return (0);
1095 
1096 	memset(buf, 0, len);
1097 
1098 	enc = AFMT_ENCODING(afmt);
1099 	ch = AFMT_CHANNEL(afmt);
1100 	ext = AFMT_EXTCHANNEL(afmt);
1101 	/* check there is at least one channel */
1102 	if (ch <= ext)
1103 		return (0);
1104 	for (i = 0; afmt_tab[i].name != NULL; i++) {
1105 		if (enc != afmt_tab[i].afmt)
1106 			continue;
1107 		/* found a match */
1108 		snprintf(buf, len, "%s:%d.%d",
1109 		    afmt_tab[i].name, ch - ext, ext);
1110 		return (SND_FORMAT(enc, ch, ext));
1111 	}
1112 	return (0);
1113 }
1114 
1115 int
1116 chn_reset(struct pcm_channel *c, uint32_t fmt, uint32_t spd)
1117 {
1118 	int r;
1119 
1120 	CHN_LOCKASSERT(c);
1121 	c->feedcount = 0;
1122 	c->flags &= CHN_F_RESET;
1123 	c->interrupts = 0;
1124 	c->timeout = 1;
1125 	c->xruns = 0;
1126 
1127 	c->flags |= (pcm_getflags(c->dev) & SD_F_BITPERFECT) ?
1128 	    CHN_F_BITPERFECT : 0;
1129 
1130 	r = CHANNEL_RESET(c->methods, c->devinfo);
1131 	if (r == 0 && fmt != 0 && spd != 0) {
1132 		r = chn_setparam(c, fmt, spd);
1133 		fmt = 0;
1134 		spd = 0;
1135 	}
1136 	if (r == 0 && fmt != 0)
1137 		r = chn_setformat(c, fmt);
1138 	if (r == 0 && spd != 0)
1139 		r = chn_setspeed(c, spd);
1140 	if (r == 0)
1141 		r = chn_setlatency(c, chn_latency);
1142 	if (r == 0) {
1143 		chn_resetbuf(c);
1144 		r = CHANNEL_RESETDONE(c->methods, c->devinfo);
1145 	}
1146 	return r;
1147 }
1148 
1149 static struct unrhdr *
1150 chn_getunr(struct snddev_info *d, int type)
1151 {
1152 	switch (type) {
1153 	case PCMDIR_PLAY:
1154 		return (d->p_unr);
1155 	case PCMDIR_PLAY_VIRTUAL:
1156 		return (d->vp_unr);
1157 	case PCMDIR_REC:
1158 		return (d->r_unr);
1159 	case PCMDIR_REC_VIRTUAL:
1160 		return (d->vr_unr);
1161 	default:
1162 		__assert_unreachable();
1163 	}
1164 
1165 }
1166 
1167 char *
1168 chn_mkname(char *buf, size_t len, struct pcm_channel *c)
1169 {
1170 	const char *str;
1171 
1172 	KASSERT(buf != NULL && len != 0,
1173 	    ("%s(): bogus buf=%p len=%zu", __func__, buf, len));
1174 
1175 	switch (c->type) {
1176 	case PCMDIR_PLAY:
1177 		str = "play";
1178 		break;
1179 	case PCMDIR_PLAY_VIRTUAL:
1180 		str = "virtual_play";
1181 		break;
1182 	case PCMDIR_REC:
1183 		str = "record";
1184 		break;
1185 	case PCMDIR_REC_VIRTUAL:
1186 		str = "virtual_record";
1187 		break;
1188 	default:
1189 		__assert_unreachable();
1190 	}
1191 
1192 	snprintf(buf, len, "dsp%d.%s.%d",
1193 	    device_get_unit(c->dev), str, c->unit);
1194 
1195 	return (buf);
1196 }
1197 
1198 struct pcm_channel *
1199 chn_init(struct snddev_info *d, struct pcm_channel *parent, kobj_class_t cls,
1200     int dir, void *devinfo)
1201 {
1202 	struct pcm_channel *c;
1203 	struct feeder_class *fc;
1204 	struct snd_dbuf *b, *bs;
1205 	char buf[CHN_NAMELEN];
1206 	int i, direction;
1207 
1208 	PCM_BUSYASSERT(d);
1209 	PCM_LOCKASSERT(d);
1210 
1211 	switch (dir) {
1212 	case PCMDIR_PLAY:
1213 	case PCMDIR_PLAY_VIRTUAL:
1214 		direction = PCMDIR_PLAY;
1215 		break;
1216 	case PCMDIR_REC:
1217 	case PCMDIR_REC_VIRTUAL:
1218 		direction = PCMDIR_REC;
1219 		break;
1220 	default:
1221 		device_printf(d->dev,
1222 		    "%s(): invalid channel direction: %d\n",
1223 		    __func__, dir);
1224 		return (NULL);
1225 	}
1226 
1227 	PCM_UNLOCK(d);
1228 	b = NULL;
1229 	bs = NULL;
1230 
1231 	c = malloc(sizeof(*c), M_DEVBUF, M_WAITOK | M_ZERO);
1232 	c->methods = kobj_create(cls, M_DEVBUF, M_WAITOK | M_ZERO);
1233 	chn_lockinit(c, dir);
1234 	CHN_INIT(c, children);
1235 	CHN_INIT(c, children.busy);
1236 	c->direction = direction;
1237 	c->type = dir;
1238 	c->unit = alloc_unr(chn_getunr(d, c->type));
1239 	c->format = SND_FORMAT(AFMT_U8, 1, 0);
1240 	c->speed = DSP_DEFAULT_SPEED;
1241 	c->pid = -1;
1242 	c->latency = -1;
1243 	c->timeout = 1;
1244 	strlcpy(c->comm, CHN_COMM_UNUSED, sizeof(c->comm));
1245 	c->parentsnddev = d;
1246 	c->parentchannel = parent;
1247 	c->dev = d->dev;
1248 	c->trigger = PCMTRIG_STOP;
1249 	strlcpy(c->name, chn_mkname(buf, sizeof(buf), c), sizeof(c->name));
1250 
1251 	c->matrix = *feeder_matrix_id_map(SND_CHN_MATRIX_1_0);
1252 	c->matrix.id = SND_CHN_MATRIX_PCMCHANNEL;
1253 
1254 	for (i = 0; i < SND_CHN_T_MAX; i++)
1255 		c->volume[SND_VOL_C_MASTER][i] = SND_VOL_0DB_MASTER;
1256 
1257 	c->volume[SND_VOL_C_MASTER][SND_CHN_T_VOL_0DB] = SND_VOL_0DB_MASTER;
1258 	c->volume[SND_VOL_C_PCM][SND_CHN_T_VOL_0DB] = chn_vol_0db_pcm;
1259 
1260 	CHN_LOCK(c);
1261 	chn_vpc_reset(c, SND_VOL_C_PCM, 1);
1262 	CHN_UNLOCK(c);
1263 
1264 	fc = feeder_getclass(NULL);
1265 	if (fc == NULL) {
1266 		device_printf(d->dev, "%s(): failed to get feeder class\n",
1267 		    __func__);
1268 		goto fail;
1269 	}
1270 	if (feeder_add(c, fc, NULL)) {
1271 		device_printf(d->dev, "%s(): failed to add feeder\n", __func__);
1272 		goto fail;
1273 	}
1274 
1275 	b = sndbuf_create(c->dev, c->name, "primary", c);
1276 	bs = sndbuf_create(c->dev, c->name, "secondary", c);
1277 	if (b == NULL || bs == NULL) {
1278 		device_printf(d->dev, "%s(): failed to create %s buffer\n",
1279 		    __func__, b == NULL ? "hardware" : "software");
1280 		goto fail;
1281 	}
1282 	c->bufhard = b;
1283 	c->bufsoft = bs;
1284 
1285 	c->devinfo = CHANNEL_INIT(c->methods, devinfo, b, c, direction);
1286 	if (c->devinfo == NULL) {
1287 		device_printf(d->dev, "%s(): CHANNEL_INIT() failed\n", __func__);
1288 		goto fail;
1289 	}
1290 
1291 	if ((sndbuf_getsize(b) == 0) && ((c->flags & CHN_F_VIRTUAL) == 0)) {
1292 		device_printf(d->dev, "%s(): hardware buffer's size is 0\n",
1293 		    __func__);
1294 		goto fail;
1295 	}
1296 
1297 	sndbuf_setfmt(b, c->format);
1298 	sndbuf_setspd(b, c->speed);
1299 	sndbuf_setfmt(bs, c->format);
1300 	sndbuf_setspd(bs, c->speed);
1301 	sndbuf_setup(bs, NULL, 0);
1302 
1303 	/**
1304 	 * @todo Should this be moved somewhere else?  The primary buffer
1305 	 * 	 is allocated by the driver or via DMA map setup, and tmpbuf
1306 	 * 	 seems to only come into existence in sndbuf_resize().
1307 	 */
1308 	if (c->direction == PCMDIR_PLAY) {
1309 		bs->sl = sndbuf_getmaxsize(bs);
1310 		bs->shadbuf = malloc(bs->sl, M_DEVBUF, M_WAITOK);
1311 	}
1312 
1313 	PCM_LOCK(d);
1314 	CHN_INSERT_SORT_ASCEND(d, c, channels.pcm);
1315 
1316 	switch (c->type) {
1317 	case PCMDIR_PLAY:
1318 		d->playcount++;
1319 		break;
1320 	case PCMDIR_PLAY_VIRTUAL:
1321 		d->pvchancount++;
1322 		break;
1323 	case PCMDIR_REC:
1324 		d->reccount++;
1325 		break;
1326 	case PCMDIR_REC_VIRTUAL:
1327 		d->rvchancount++;
1328 		break;
1329 	default:
1330 		__assert_unreachable();
1331 	}
1332 
1333 	return (c);
1334 
1335 fail:
1336 	free_unr(chn_getunr(d, c->type), c->unit);
1337 	feeder_remove(c);
1338 	if (c->devinfo && CHANNEL_FREE(c->methods, c->devinfo))
1339 		sndbuf_free(b);
1340 	if (bs)
1341 		sndbuf_destroy(bs);
1342 	if (b)
1343 		sndbuf_destroy(b);
1344 	CHN_LOCK(c);
1345 	chn_lockdestroy(c);
1346 
1347 	kobj_delete(c->methods, M_DEVBUF);
1348 	free(c, M_DEVBUF);
1349 
1350 	PCM_LOCK(d);
1351 
1352 	return (NULL);
1353 }
1354 
1355 void
1356 chn_kill(struct pcm_channel *c)
1357 {
1358 	struct snddev_info *d = c->parentsnddev;
1359 	struct snd_dbuf *b = c->bufhard;
1360 	struct snd_dbuf *bs = c->bufsoft;
1361 
1362 	PCM_BUSYASSERT(c->parentsnddev);
1363 
1364 	PCM_LOCK(d);
1365 	CHN_REMOVE(d, c, channels.pcm);
1366 
1367 	switch (c->type) {
1368 	case PCMDIR_PLAY:
1369 		d->playcount--;
1370 		break;
1371 	case PCMDIR_PLAY_VIRTUAL:
1372 		d->pvchancount--;
1373 		break;
1374 	case PCMDIR_REC:
1375 		d->reccount--;
1376 		break;
1377 	case PCMDIR_REC_VIRTUAL:
1378 		d->rvchancount--;
1379 		break;
1380 	default:
1381 		__assert_unreachable();
1382 	}
1383 	PCM_UNLOCK(d);
1384 
1385 	if (CHN_STARTED(c)) {
1386 		CHN_LOCK(c);
1387 		chn_trigger(c, PCMTRIG_ABORT);
1388 		CHN_UNLOCK(c);
1389 	}
1390 	free_unr(chn_getunr(c->parentsnddev, c->type), c->unit);
1391 	feeder_remove(c);
1392 	if (CHANNEL_FREE(c->methods, c->devinfo))
1393 		sndbuf_free(b);
1394 	sndbuf_destroy(bs);
1395 	sndbuf_destroy(b);
1396 	CHN_LOCK(c);
1397 	c->flags |= CHN_F_DEAD;
1398 	chn_lockdestroy(c);
1399 	kobj_delete(c->methods, M_DEVBUF);
1400 	free(c, M_DEVBUF);
1401 }
1402 
1403 void
1404 chn_shutdown(struct pcm_channel *c)
1405 {
1406 	CHN_LOCKASSERT(c);
1407 
1408 	chn_wakeup(c);
1409 	c->flags |= CHN_F_DEAD;
1410 }
1411 
1412 /* release a locked channel and unlock it */
1413 int
1414 chn_release(struct pcm_channel *c)
1415 {
1416 	PCM_BUSYASSERT(c->parentsnddev);
1417 	CHN_LOCKASSERT(c);
1418 
1419 	c->flags &= ~CHN_F_BUSY;
1420 	c->pid = -1;
1421 	strlcpy(c->comm, CHN_COMM_UNUSED, sizeof(c->comm));
1422 	CHN_UNLOCK(c);
1423 
1424 	return (0);
1425 }
1426 
1427 int
1428 chn_setvolume_multi(struct pcm_channel *c, int vc, int left, int right,
1429     int center)
1430 {
1431 	int i, ret;
1432 
1433 	ret = 0;
1434 
1435 	for (i = 0; i < SND_CHN_T_MAX; i++) {
1436 		if ((1 << i) & SND_CHN_LEFT_MASK)
1437 			ret |= chn_setvolume_matrix(c, vc, i, left);
1438 		else if ((1 << i) & SND_CHN_RIGHT_MASK)
1439 			ret |= chn_setvolume_matrix(c, vc, i, right) << 8;
1440 		else
1441 			ret |= chn_setvolume_matrix(c, vc, i, center) << 16;
1442 	}
1443 
1444 	return (ret);
1445 }
1446 
1447 int
1448 chn_setvolume_matrix(struct pcm_channel *c, int vc, int vt, int val)
1449 {
1450 	int i;
1451 
1452 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1453 	    (vc == SND_VOL_C_MASTER || (vc & 1)) &&
1454 	    (vt == SND_CHN_T_VOL_0DB || (vt >= SND_CHN_T_BEGIN &&
1455 	    vt <= SND_CHN_T_END)) && (vt != SND_CHN_T_VOL_0DB ||
1456 	    (val >= SND_VOL_0DB_MIN && val <= SND_VOL_0DB_MAX)),
1457 	    ("%s(): invalid volume matrix c=%p vc=%d vt=%d val=%d",
1458 	    __func__, c, vc, vt, val));
1459 	CHN_LOCKASSERT(c);
1460 
1461 	if (val < 0)
1462 		val = 0;
1463 	if (val > 100)
1464 		val = 100;
1465 
1466 	c->volume[vc][vt] = val;
1467 
1468 	/*
1469 	 * Do relative calculation here and store it into class + 1
1470 	 * to ease the job of feeder_volume.
1471 	 */
1472 	if (vc == SND_VOL_C_MASTER) {
1473 		for (vc = SND_VOL_C_BEGIN; vc <= SND_VOL_C_END;
1474 		    vc += SND_VOL_C_STEP)
1475 			c->volume[SND_VOL_C_VAL(vc)][vt] =
1476 			    SND_VOL_CALC_VAL(c->volume, vc, vt);
1477 	} else if (vc & 1) {
1478 		if (vt == SND_CHN_T_VOL_0DB)
1479 			for (i = SND_CHN_T_BEGIN; i <= SND_CHN_T_END;
1480 			    i += SND_CHN_T_STEP) {
1481 				c->volume[SND_VOL_C_VAL(vc)][i] =
1482 				    SND_VOL_CALC_VAL(c->volume, vc, i);
1483 			}
1484 		else
1485 			c->volume[SND_VOL_C_VAL(vc)][vt] =
1486 			    SND_VOL_CALC_VAL(c->volume, vc, vt);
1487 	}
1488 
1489 	return (val);
1490 }
1491 
1492 int
1493 chn_getvolume_matrix(struct pcm_channel *c, int vc, int vt)
1494 {
1495 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1496 	    (vt == SND_CHN_T_VOL_0DB ||
1497 	    (vt >= SND_CHN_T_BEGIN && vt <= SND_CHN_T_END)),
1498 	    ("%s(): invalid volume matrix c=%p vc=%d vt=%d",
1499 	    __func__, c, vc, vt));
1500 	CHN_LOCKASSERT(c);
1501 
1502 	return (c->volume[vc][vt]);
1503 }
1504 
1505 int
1506 chn_setmute_multi(struct pcm_channel *c, int vc, int mute)
1507 {
1508 	int i, ret;
1509 
1510 	ret = 0;
1511 
1512 	for (i = 0; i < SND_CHN_T_MAX; i++) {
1513 		if ((1 << i) & SND_CHN_LEFT_MASK)
1514 			ret |= chn_setmute_matrix(c, vc, i, mute);
1515 		else if ((1 << i) & SND_CHN_RIGHT_MASK)
1516 			ret |= chn_setmute_matrix(c, vc, i, mute) << 8;
1517 		else
1518 			ret |= chn_setmute_matrix(c, vc, i, mute) << 16;
1519 	}
1520 	return (ret);
1521 }
1522 
1523 int
1524 chn_setmute_matrix(struct pcm_channel *c, int vc, int vt, int mute)
1525 {
1526 	int i;
1527 
1528 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1529 	    (vc == SND_VOL_C_MASTER || (vc & 1)) &&
1530 	    (vt == SND_CHN_T_VOL_0DB || (vt >= SND_CHN_T_BEGIN && vt <= SND_CHN_T_END)),
1531 	    ("%s(): invalid mute matrix c=%p vc=%d vt=%d mute=%d",
1532 	    __func__, c, vc, vt, mute));
1533 
1534 	CHN_LOCKASSERT(c);
1535 
1536 	mute = (mute != 0);
1537 
1538 	c->muted[vc][vt] = mute;
1539 
1540 	/*
1541 	 * Do relative calculation here and store it into class + 1
1542 	 * to ease the job of feeder_volume.
1543 	 */
1544 	if (vc == SND_VOL_C_MASTER) {
1545 		for (vc = SND_VOL_C_BEGIN; vc <= SND_VOL_C_END;
1546 		    vc += SND_VOL_C_STEP)
1547 			c->muted[SND_VOL_C_VAL(vc)][vt] = mute;
1548 	} else if (vc & 1) {
1549 		if (vt == SND_CHN_T_VOL_0DB) {
1550 			for (i = SND_CHN_T_BEGIN; i <= SND_CHN_T_END;
1551 			    i += SND_CHN_T_STEP) {
1552 				c->muted[SND_VOL_C_VAL(vc)][i] = mute;
1553 			}
1554 		} else {
1555 			c->muted[SND_VOL_C_VAL(vc)][vt] = mute;
1556 		}
1557 	}
1558 	return (mute);
1559 }
1560 
1561 int
1562 chn_getmute_matrix(struct pcm_channel *c, int vc, int vt)
1563 {
1564 	KASSERT(c != NULL && vc >= SND_VOL_C_MASTER && vc < SND_VOL_C_MAX &&
1565 	    (vt == SND_CHN_T_VOL_0DB ||
1566 	    (vt >= SND_CHN_T_BEGIN && vt <= SND_CHN_T_END)),
1567 	    ("%s(): invalid mute matrix c=%p vc=%d vt=%d",
1568 	    __func__, c, vc, vt));
1569 	CHN_LOCKASSERT(c);
1570 
1571 	return (c->muted[vc][vt]);
1572 }
1573 
1574 struct pcmchan_matrix *
1575 chn_getmatrix(struct pcm_channel *c)
1576 {
1577 
1578 	KASSERT(c != NULL, ("%s(): NULL channel", __func__));
1579 	CHN_LOCKASSERT(c);
1580 
1581 	if (!(c->format & AFMT_CONVERTIBLE))
1582 		return (NULL);
1583 
1584 	return (&c->matrix);
1585 }
1586 
1587 int
1588 chn_setmatrix(struct pcm_channel *c, struct pcmchan_matrix *m)
1589 {
1590 
1591 	KASSERT(c != NULL && m != NULL,
1592 	    ("%s(): NULL channel or matrix", __func__));
1593 	CHN_LOCKASSERT(c);
1594 
1595 	if (!(c->format & AFMT_CONVERTIBLE))
1596 		return (EINVAL);
1597 
1598 	c->matrix = *m;
1599 	c->matrix.id = SND_CHN_MATRIX_PCMCHANNEL;
1600 
1601 	return (chn_setformat(c, SND_FORMAT(c->format, m->channels, m->ext)));
1602 }
1603 
1604 /*
1605  * XXX chn_oss_* exists for the sake of compatibility.
1606  */
1607 int
1608 chn_oss_getorder(struct pcm_channel *c, unsigned long long *map)
1609 {
1610 
1611 	KASSERT(c != NULL && map != NULL,
1612 	    ("%s(): NULL channel or map", __func__));
1613 	CHN_LOCKASSERT(c);
1614 
1615 	if (!(c->format & AFMT_CONVERTIBLE))
1616 		return (EINVAL);
1617 
1618 	return (feeder_matrix_oss_get_channel_order(&c->matrix, map));
1619 }
1620 
1621 int
1622 chn_oss_setorder(struct pcm_channel *c, unsigned long long *map)
1623 {
1624 	struct pcmchan_matrix m;
1625 	int ret;
1626 
1627 	KASSERT(c != NULL && map != NULL,
1628 	    ("%s(): NULL channel or map", __func__));
1629 	CHN_LOCKASSERT(c);
1630 
1631 	if (!(c->format & AFMT_CONVERTIBLE))
1632 		return (EINVAL);
1633 
1634 	m = c->matrix;
1635 	ret = feeder_matrix_oss_set_channel_order(&m, map);
1636 	if (ret != 0)
1637 		return (ret);
1638 
1639 	return (chn_setmatrix(c, &m));
1640 }
1641 
1642 #define SND_CHN_OSS_FRONT	(SND_CHN_T_MASK_FL | SND_CHN_T_MASK_FR)
1643 #define SND_CHN_OSS_SURR	(SND_CHN_T_MASK_SL | SND_CHN_T_MASK_SR)
1644 #define SND_CHN_OSS_CENTER_LFE	(SND_CHN_T_MASK_FC | SND_CHN_T_MASK_LF)
1645 #define SND_CHN_OSS_REAR	(SND_CHN_T_MASK_BL | SND_CHN_T_MASK_BR)
1646 
1647 int
1648 chn_oss_getmask(struct pcm_channel *c, uint32_t *retmask)
1649 {
1650 	struct pcmchan_matrix *m;
1651 	struct pcmchan_caps *caps;
1652 	uint32_t i, format;
1653 
1654 	KASSERT(c != NULL && retmask != NULL,
1655 	    ("%s(): NULL channel or retmask", __func__));
1656 	CHN_LOCKASSERT(c);
1657 
1658 	caps = chn_getcaps(c);
1659 	if (caps == NULL || caps->fmtlist == NULL)
1660 		return (ENODEV);
1661 
1662 	for (i = 0; caps->fmtlist[i] != 0; i++) {
1663 		format = caps->fmtlist[i];
1664 		if (!(format & AFMT_CONVERTIBLE)) {
1665 			*retmask |= DSP_BIND_SPDIF;
1666 			continue;
1667 		}
1668 		m = CHANNEL_GETMATRIX(c->methods, c->devinfo, format);
1669 		if (m == NULL)
1670 			continue;
1671 		if (m->mask & SND_CHN_OSS_FRONT)
1672 			*retmask |= DSP_BIND_FRONT;
1673 		if (m->mask & SND_CHN_OSS_SURR)
1674 			*retmask |= DSP_BIND_SURR;
1675 		if (m->mask & SND_CHN_OSS_CENTER_LFE)
1676 			*retmask |= DSP_BIND_CENTER_LFE;
1677 		if (m->mask & SND_CHN_OSS_REAR)
1678 			*retmask |= DSP_BIND_REAR;
1679 	}
1680 
1681 	/* report software-supported binding mask */
1682 	if (!CHN_BITPERFECT(c) && report_soft_matrix)
1683 		*retmask |= DSP_BIND_FRONT | DSP_BIND_SURR |
1684 		    DSP_BIND_CENTER_LFE | DSP_BIND_REAR;
1685 
1686 	return (0);
1687 }
1688 
1689 void
1690 chn_vpc_reset(struct pcm_channel *c, int vc, int force)
1691 {
1692 	int i;
1693 
1694 	KASSERT(c != NULL && vc >= SND_VOL_C_BEGIN && vc <= SND_VOL_C_END,
1695 	    ("%s(): invalid reset c=%p vc=%d", __func__, c, vc));
1696 	CHN_LOCKASSERT(c);
1697 
1698 	if (force == 0 && chn_vpc_autoreset == 0)
1699 		return;
1700 
1701 	for (i = SND_CHN_T_BEGIN; i <= SND_CHN_T_END; i += SND_CHN_T_STEP)
1702 		CHN_SETVOLUME(c, vc, i, c->volume[vc][SND_CHN_T_VOL_0DB]);
1703 }
1704 
1705 static u_int32_t
1706 round_pow2(u_int32_t v)
1707 {
1708 	u_int32_t ret;
1709 
1710 	if (v < 2)
1711 		v = 2;
1712 	ret = 0;
1713 	while (v >> ret)
1714 		ret++;
1715 	ret = 1 << (ret - 1);
1716 	while (ret < v)
1717 		ret <<= 1;
1718 	return ret;
1719 }
1720 
1721 static u_int32_t
1722 round_blksz(u_int32_t v, int round)
1723 {
1724 	u_int32_t ret, tmp;
1725 
1726 	if (round < 1)
1727 		round = 1;
1728 
1729 	ret = min(round_pow2(v), CHN_2NDBUFMAXSIZE >> 1);
1730 
1731 	if (ret > v && (ret >> 1) > 0 && (ret >> 1) >= ((v * 3) >> 2))
1732 		ret >>= 1;
1733 
1734 	tmp = ret - (ret % round);
1735 	while (tmp < 16 || tmp < round) {
1736 		ret <<= 1;
1737 		tmp = ret - (ret % round);
1738 	}
1739 
1740 	return ret;
1741 }
1742 
1743 /*
1744  * 4Front call it DSP Policy, while we call it "Latency Profile". The idea
1745  * is to keep 2nd buffer short so that it doesn't cause long queue during
1746  * buffer transfer.
1747  *
1748  *    Latency reference table for 48khz stereo 16bit: (PLAY)
1749  *
1750  *      +---------+------------+-----------+------------+
1751  *      | Latency | Blockcount | Blocksize | Buffersize |
1752  *      +---------+------------+-----------+------------+
1753  *      |     0   |       2    |   64      |    128     |
1754  *      +---------+------------+-----------+------------+
1755  *      |     1   |       4    |   128     |    512     |
1756  *      +---------+------------+-----------+------------+
1757  *      |     2   |       8    |   512     |    4096    |
1758  *      +---------+------------+-----------+------------+
1759  *      |     3   |      16    |   512     |    8192    |
1760  *      +---------+------------+-----------+------------+
1761  *      |     4   |      32    |   512     |    16384   |
1762  *      +---------+------------+-----------+------------+
1763  *      |     5   |      32    |   1024    |    32768   |
1764  *      +---------+------------+-----------+------------+
1765  *      |     6   |      16    |   2048    |    32768   |
1766  *      +---------+------------+-----------+------------+
1767  *      |     7   |       8    |   4096    |    32768   |
1768  *      +---------+------------+-----------+------------+
1769  *      |     8   |       4    |   8192    |    32768   |
1770  *      +---------+------------+-----------+------------+
1771  *      |     9   |       2    |   16384   |    32768   |
1772  *      +---------+------------+-----------+------------+
1773  *      |    10   |       2    |   32768   |    65536   |
1774  *      +---------+------------+-----------+------------+
1775  *
1776  * Recording need a different reference table. All we care is
1777  * gobbling up everything within reasonable buffering threshold.
1778  *
1779  *    Latency reference table for 48khz stereo 16bit: (REC)
1780  *
1781  *      +---------+------------+-----------+------------+
1782  *      | Latency | Blockcount | Blocksize | Buffersize |
1783  *      +---------+------------+-----------+------------+
1784  *      |     0   |     512    |   32      |    16384   |
1785  *      +---------+------------+-----------+------------+
1786  *      |     1   |     256    |   64      |    16384   |
1787  *      +---------+------------+-----------+------------+
1788  *      |     2   |     128    |   128     |    16384   |
1789  *      +---------+------------+-----------+------------+
1790  *      |     3   |      64    |   256     |    16384   |
1791  *      +---------+------------+-----------+------------+
1792  *      |     4   |      32    |   512     |    16384   |
1793  *      +---------+------------+-----------+------------+
1794  *      |     5   |      32    |   1024    |    32768   |
1795  *      +---------+------------+-----------+------------+
1796  *      |     6   |      16    |   2048    |    32768   |
1797  *      +---------+------------+-----------+------------+
1798  *      |     7   |       8    |   4096    |    32768   |
1799  *      +---------+------------+-----------+------------+
1800  *      |     8   |       4    |   8192    |    32768   |
1801  *      +---------+------------+-----------+------------+
1802  *      |     9   |       2    |   16384   |    32768   |
1803  *      +---------+------------+-----------+------------+
1804  *      |    10   |       2    |   32768   |    65536   |
1805  *      +---------+------------+-----------+------------+
1806  *
1807  * Calculations for other data rate are entirely based on these reference
1808  * tables. For normal operation, Latency 5 seems give the best, well
1809  * balanced performance for typical workload. Anything below 5 will
1810  * eat up CPU to keep up with increasing context switches because of
1811  * shorter buffer space and usually require the application to handle it
1812  * aggressively through possibly real time programming technique.
1813  *
1814  */
1815 #define CHN_LATENCY_PBLKCNT_REF				\
1816 	{{1, 2, 3, 4, 5, 5, 4, 3, 2, 1, 1},		\
1817 	{1, 2, 3, 4, 5, 5, 4, 3, 2, 1, 1}}
1818 #define CHN_LATENCY_PBUFSZ_REF				\
1819 	{{7, 9, 12, 13, 14, 15, 15, 15, 15, 15, 16},	\
1820 	{11, 12, 13, 14, 15, 16, 16, 16, 16, 16, 17}}
1821 
1822 #define CHN_LATENCY_RBLKCNT_REF				\
1823 	{{9, 8, 7, 6, 5, 5, 4, 3, 2, 1, 1},		\
1824 	{9, 8, 7, 6, 5, 5, 4, 3, 2, 1, 1}}
1825 #define CHN_LATENCY_RBUFSZ_REF				\
1826 	{{14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 16},	\
1827 	{15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 17}}
1828 
1829 #define CHN_LATENCY_DATA_REF	192000 /* 48khz stereo 16bit ~ 48000 x 2 x 2 */
1830 
1831 static int
1832 chn_calclatency(int dir, int latency, int bps, u_int32_t datarate,
1833 				u_int32_t max, int *rblksz, int *rblkcnt)
1834 {
1835 	static int pblkcnts[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1836 	    CHN_LATENCY_PBLKCNT_REF;
1837 	static int  pbufszs[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1838 	    CHN_LATENCY_PBUFSZ_REF;
1839 	static int rblkcnts[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1840 	    CHN_LATENCY_RBLKCNT_REF;
1841 	static int  rbufszs[CHN_LATENCY_PROFILE_MAX + 1][CHN_LATENCY_MAX + 1] =
1842 	    CHN_LATENCY_RBUFSZ_REF;
1843 	u_int32_t bufsz;
1844 	int lprofile, blksz, blkcnt;
1845 
1846 	if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX ||
1847 	    bps < 1 || datarate < 1 ||
1848 	    !(dir == PCMDIR_PLAY || dir == PCMDIR_REC)) {
1849 		if (rblksz != NULL)
1850 			*rblksz = CHN_2NDBUFMAXSIZE >> 1;
1851 		if (rblkcnt != NULL)
1852 			*rblkcnt = 2;
1853 		printf("%s(): FAILED dir=%d latency=%d bps=%d "
1854 		    "datarate=%u max=%u\n",
1855 		    __func__, dir, latency, bps, datarate, max);
1856 		return CHN_2NDBUFMAXSIZE;
1857 	}
1858 
1859 	lprofile = chn_latency_profile;
1860 
1861 	if (dir == PCMDIR_PLAY) {
1862 		blkcnt = pblkcnts[lprofile][latency];
1863 		bufsz = pbufszs[lprofile][latency];
1864 	} else {
1865 		blkcnt = rblkcnts[lprofile][latency];
1866 		bufsz = rbufszs[lprofile][latency];
1867 	}
1868 
1869 	bufsz = round_pow2(snd_xbytes(1 << bufsz, CHN_LATENCY_DATA_REF,
1870 	    datarate));
1871 	if (bufsz > max)
1872 		bufsz = max;
1873 	blksz = round_blksz(bufsz >> blkcnt, bps);
1874 
1875 	if (rblksz != NULL)
1876 		*rblksz = blksz;
1877 	if (rblkcnt != NULL)
1878 		*rblkcnt = 1 << blkcnt;
1879 
1880 	return blksz << blkcnt;
1881 }
1882 
1883 static int
1884 chn_resizebuf(struct pcm_channel *c, int latency,
1885 					int blkcnt, int blksz)
1886 {
1887 	struct snd_dbuf *b, *bs, *pb;
1888 	int sblksz, sblkcnt, hblksz, hblkcnt, limit = 0, nsblksz, nsblkcnt;
1889 	int ret;
1890 
1891 	CHN_LOCKASSERT(c);
1892 
1893 	if ((c->flags & (CHN_F_MMAP | CHN_F_TRIGGERED)) ||
1894 	    !(c->direction == PCMDIR_PLAY || c->direction == PCMDIR_REC))
1895 		return EINVAL;
1896 
1897 	if (latency == -1) {
1898 		c->latency = -1;
1899 		latency = chn_latency;
1900 	} else if (latency == -2) {
1901 		latency = c->latency;
1902 		if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX)
1903 			latency = chn_latency;
1904 	} else if (latency < CHN_LATENCY_MIN || latency > CHN_LATENCY_MAX)
1905 		return EINVAL;
1906 	else {
1907 		c->latency = latency;
1908 	}
1909 
1910 	bs = c->bufsoft;
1911 	b = c->bufhard;
1912 
1913 	if (!(blksz == 0 || blkcnt == -1) &&
1914 	    (blksz < 16 || blksz < sndbuf_getalign(bs) || blkcnt < 2 ||
1915 	    (blksz * blkcnt) > CHN_2NDBUFMAXSIZE))
1916 		return EINVAL;
1917 
1918 	chn_calclatency(c->direction, latency, sndbuf_getalign(bs),
1919 	    sndbuf_getalign(bs) * sndbuf_getspd(bs), CHN_2NDBUFMAXSIZE,
1920 	    &sblksz, &sblkcnt);
1921 
1922 	if (blksz == 0 || blkcnt == -1) {
1923 		if (blkcnt == -1)
1924 			c->flags &= ~CHN_F_HAS_SIZE;
1925 		if (c->flags & CHN_F_HAS_SIZE) {
1926 			blksz = sndbuf_getblksz(bs);
1927 			blkcnt = sndbuf_getblkcnt(bs);
1928 		}
1929 	} else
1930 		c->flags |= CHN_F_HAS_SIZE;
1931 
1932 	if (c->flags & CHN_F_HAS_SIZE) {
1933 		/*
1934 		 * The application has requested their own blksz/blkcnt.
1935 		 * Just obey with it, and let them toast alone. We can
1936 		 * clamp it to the nearest latency profile, but that would
1937 		 * defeat the purpose of having custom control. The least
1938 		 * we can do is round it to the nearest ^2 and align it.
1939 		 */
1940 		sblksz = round_blksz(blksz, sndbuf_getalign(bs));
1941 		sblkcnt = round_pow2(blkcnt);
1942 	}
1943 
1944 	if (c->parentchannel != NULL) {
1945 		pb = c->parentchannel->bufsoft;
1946 		CHN_UNLOCK(c);
1947 		CHN_LOCK(c->parentchannel);
1948 		chn_notify(c->parentchannel, CHN_N_BLOCKSIZE);
1949 		CHN_UNLOCK(c->parentchannel);
1950 		CHN_LOCK(c);
1951 		if (c->direction == PCMDIR_PLAY) {
1952 			limit = (pb != NULL) ?
1953 			    sndbuf_xbytes(sndbuf_getsize(pb), pb, bs) : 0;
1954 		} else {
1955 			limit = (pb != NULL) ?
1956 			    sndbuf_xbytes(sndbuf_getblksz(pb), pb, bs) * 2 : 0;
1957 		}
1958 	} else {
1959 		hblkcnt = 2;
1960 		if (c->flags & CHN_F_HAS_SIZE) {
1961 			hblksz = round_blksz(sndbuf_xbytes(sblksz, bs, b),
1962 			    sndbuf_getalign(b));
1963 			hblkcnt = round_pow2(sndbuf_getblkcnt(bs));
1964 		} else
1965 			chn_calclatency(c->direction, latency,
1966 			    sndbuf_getalign(b),
1967 			    sndbuf_getalign(b) * sndbuf_getspd(b),
1968 			    CHN_2NDBUFMAXSIZE, &hblksz, &hblkcnt);
1969 
1970 		if ((hblksz << 1) > sndbuf_getmaxsize(b))
1971 			hblksz = round_blksz(sndbuf_getmaxsize(b) >> 1,
1972 			    sndbuf_getalign(b));
1973 
1974 		while ((hblksz * hblkcnt) > sndbuf_getmaxsize(b)) {
1975 			if (hblkcnt < 4)
1976 				hblksz >>= 1;
1977 			else
1978 				hblkcnt >>= 1;
1979 		}
1980 
1981 		hblksz -= hblksz % sndbuf_getalign(b);
1982 
1983 #if 0
1984 		hblksz = sndbuf_getmaxsize(b) >> 1;
1985 		hblksz -= hblksz % sndbuf_getalign(b);
1986 		hblkcnt = 2;
1987 #endif
1988 
1989 		CHN_UNLOCK(c);
1990 		if (chn_usefrags == 0 ||
1991 		    CHANNEL_SETFRAGMENTS(c->methods, c->devinfo,
1992 		    hblksz, hblkcnt) != 0)
1993 			sndbuf_setblksz(b, CHANNEL_SETBLOCKSIZE(c->methods,
1994 			    c->devinfo, hblksz));
1995 		CHN_LOCK(c);
1996 
1997 		if (!CHN_EMPTY(c, children)) {
1998 			nsblksz = round_blksz(
1999 			    sndbuf_xbytes(sndbuf_getblksz(b), b, bs),
2000 			    sndbuf_getalign(bs));
2001 			nsblkcnt = sndbuf_getblkcnt(b);
2002 			if (c->direction == PCMDIR_PLAY) {
2003 				do {
2004 					nsblkcnt--;
2005 				} while (nsblkcnt >= 2 &&
2006 				    nsblksz * nsblkcnt >= sblksz * sblkcnt);
2007 				nsblkcnt++;
2008 			}
2009 			sblksz = nsblksz;
2010 			sblkcnt = nsblkcnt;
2011 			limit = 0;
2012 		} else
2013 			limit = sndbuf_xbytes(sndbuf_getblksz(b), b, bs) * 2;
2014 	}
2015 
2016 	if (limit > CHN_2NDBUFMAXSIZE)
2017 		limit = CHN_2NDBUFMAXSIZE;
2018 
2019 #if 0
2020 	while (limit > 0 && (sblksz * sblkcnt) > limit) {
2021 		if (sblkcnt < 4)
2022 			break;
2023 		sblkcnt >>= 1;
2024 	}
2025 #endif
2026 
2027 	while ((sblksz * sblkcnt) < limit)
2028 		sblkcnt <<= 1;
2029 
2030 	while ((sblksz * sblkcnt) > CHN_2NDBUFMAXSIZE) {
2031 		if (sblkcnt < 4)
2032 			sblksz >>= 1;
2033 		else
2034 			sblkcnt >>= 1;
2035 	}
2036 
2037 	sblksz -= sblksz % sndbuf_getalign(bs);
2038 
2039 	if (sndbuf_getblkcnt(bs) != sblkcnt || sndbuf_getblksz(bs) != sblksz ||
2040 	    sndbuf_getsize(bs) != (sblkcnt * sblksz)) {
2041 		ret = sndbuf_remalloc(bs, sblkcnt, sblksz);
2042 		if (ret != 0) {
2043 			device_printf(c->dev, "%s(): Failed: %d %d\n",
2044 			    __func__, sblkcnt, sblksz);
2045 			return ret;
2046 		}
2047 	}
2048 
2049 	/*
2050 	 * Interrupt timeout
2051 	 */
2052 	c->timeout = ((u_int64_t)hz * sndbuf_getsize(bs)) /
2053 	    ((u_int64_t)sndbuf_getspd(bs) * sndbuf_getalign(bs));
2054 	if (c->parentchannel != NULL)
2055 		c->timeout = min(c->timeout, c->parentchannel->timeout);
2056 	if (c->timeout < 1)
2057 		c->timeout = 1;
2058 
2059 	/*
2060 	 * OSSv4 docs: "By default OSS will set the low water level equal
2061 	 * to the fragment size which is optimal in most cases."
2062 	 */
2063 	c->lw = sndbuf_getblksz(bs);
2064 	chn_resetbuf(c);
2065 
2066 	if (snd_verbose > 3)
2067 		device_printf(c->dev, "%s(): %s (%s) timeout=%u "
2068 		    "b[%d/%d/%d] bs[%d/%d/%d] limit=%d\n",
2069 		    __func__, CHN_DIRSTR(c),
2070 		    (c->flags & CHN_F_VIRTUAL) ? "virtual" : "hardware",
2071 		    c->timeout,
2072 		    sndbuf_getsize(b), sndbuf_getblksz(b),
2073 		    sndbuf_getblkcnt(b),
2074 		    sndbuf_getsize(bs), sndbuf_getblksz(bs),
2075 		    sndbuf_getblkcnt(bs), limit);
2076 
2077 	return 0;
2078 }
2079 
2080 int
2081 chn_setlatency(struct pcm_channel *c, int latency)
2082 {
2083 	CHN_LOCKASSERT(c);
2084 	/* Destroy blksz/blkcnt, enforce latency profile. */
2085 	return chn_resizebuf(c, latency, -1, 0);
2086 }
2087 
2088 int
2089 chn_setblocksize(struct pcm_channel *c, int blkcnt, int blksz)
2090 {
2091 	CHN_LOCKASSERT(c);
2092 	/* Destroy latency profile, enforce blksz/blkcnt */
2093 	return chn_resizebuf(c, -1, blkcnt, blksz);
2094 }
2095 
2096 int
2097 chn_setparam(struct pcm_channel *c, uint32_t format, uint32_t speed)
2098 {
2099 	struct pcmchan_caps *caps;
2100 	uint32_t hwspeed, delta;
2101 	int ret;
2102 
2103 	CHN_LOCKASSERT(c);
2104 
2105 	if (speed < 1 || format == 0 || CHN_STARTED(c))
2106 		return (EINVAL);
2107 
2108 	c->format = format;
2109 	c->speed = speed;
2110 
2111 	caps = chn_getcaps(c);
2112 
2113 	hwspeed = speed;
2114 	RANGE(hwspeed, caps->minspeed, caps->maxspeed);
2115 
2116 	sndbuf_setspd(c->bufhard, CHANNEL_SETSPEED(c->methods, c->devinfo,
2117 	    hwspeed));
2118 	hwspeed = sndbuf_getspd(c->bufhard);
2119 
2120 	delta = (hwspeed > speed) ? (hwspeed - speed) : (speed - hwspeed);
2121 
2122 	if (delta <= feeder_rate_round)
2123 		c->speed = hwspeed;
2124 
2125 	ret = feeder_chain(c);
2126 
2127 	if (ret == 0)
2128 		ret = CHANNEL_SETFORMAT(c->methods, c->devinfo,
2129 		    sndbuf_getfmt(c->bufhard));
2130 
2131 	if (ret == 0)
2132 		ret = chn_resizebuf(c, -2, 0, 0);
2133 
2134 	return (ret);
2135 }
2136 
2137 int
2138 chn_setspeed(struct pcm_channel *c, uint32_t speed)
2139 {
2140 	uint32_t oldformat, oldspeed, format;
2141 	int ret;
2142 
2143 #if 0
2144 	/* XXX force 48k */
2145 	if (c->format & AFMT_PASSTHROUGH)
2146 		speed = AFMT_PASSTHROUGH_RATE;
2147 #endif
2148 
2149 	oldformat = c->format;
2150 	oldspeed = c->speed;
2151 	format = oldformat;
2152 
2153 	ret = chn_setparam(c, format, speed);
2154 	if (ret != 0) {
2155 		if (snd_verbose > 3)
2156 			device_printf(c->dev,
2157 			    "%s(): Setting speed %d failed, "
2158 			    "falling back to %d\n",
2159 			    __func__, speed, oldspeed);
2160 		chn_setparam(c, c->format, oldspeed);
2161 	}
2162 
2163 	return (ret);
2164 }
2165 
2166 int
2167 chn_setformat(struct pcm_channel *c, uint32_t format)
2168 {
2169 	uint32_t oldformat, oldspeed, speed;
2170 	int ret;
2171 
2172 	/* XXX force stereo */
2173 	if ((format & AFMT_PASSTHROUGH) && AFMT_CHANNEL(format) < 2) {
2174 		format = SND_FORMAT(format, AFMT_PASSTHROUGH_CHANNEL,
2175 		    AFMT_PASSTHROUGH_EXTCHANNEL);
2176 	}
2177 
2178 	oldformat = c->format;
2179 	oldspeed = c->speed;
2180 	speed = oldspeed;
2181 
2182 	ret = chn_setparam(c, format, speed);
2183 	if (ret != 0) {
2184 		if (snd_verbose > 3)
2185 			device_printf(c->dev,
2186 			    "%s(): Format change 0x%08x failed, "
2187 			    "falling back to 0x%08x\n",
2188 			    __func__, format, oldformat);
2189 		chn_setparam(c, oldformat, oldspeed);
2190 	}
2191 
2192 	return (ret);
2193 }
2194 
2195 void
2196 chn_syncstate(struct pcm_channel *c)
2197 {
2198 	struct snddev_info *d;
2199 	struct snd_mixer *m;
2200 
2201 	d = (c != NULL) ? c->parentsnddev : NULL;
2202 	m = (d != NULL && d->mixer_dev != NULL) ? d->mixer_dev->si_drv1 :
2203 	    NULL;
2204 
2205 	if (d == NULL || m == NULL)
2206 		return;
2207 
2208 	CHN_LOCKASSERT(c);
2209 
2210 	if (c->feederflags & (1 << FEEDER_VOLUME)) {
2211 		uint32_t parent;
2212 		int vol, pvol, left, right, center;
2213 
2214 		if (c->direction == PCMDIR_PLAY &&
2215 		    (d->flags & SD_F_SOFTPCMVOL)) {
2216 			/* CHN_UNLOCK(c); */
2217 			vol = mix_get(m, SOUND_MIXER_PCM);
2218 			parent = mix_getparent(m, SOUND_MIXER_PCM);
2219 			if (parent != SOUND_MIXER_NONE)
2220 				pvol = mix_get(m, parent);
2221 			else
2222 				pvol = 100 | (100 << 8);
2223 			/* CHN_LOCK(c); */
2224 		} else {
2225 			vol = 100 | (100 << 8);
2226 			pvol = vol;
2227 		}
2228 
2229 		if (vol == -1) {
2230 			device_printf(c->dev,
2231 			    "Soft PCM Volume: Failed to read pcm "
2232 			    "default value\n");
2233 			vol = 100 | (100 << 8);
2234 		}
2235 
2236 		if (pvol == -1) {
2237 			device_printf(c->dev,
2238 			    "Soft PCM Volume: Failed to read parent "
2239 			    "default value\n");
2240 			pvol = 100 | (100 << 8);
2241 		}
2242 
2243 		left = ((vol & 0x7f) * (pvol & 0x7f)) / 100;
2244 		right = (((vol >> 8) & 0x7f) * ((pvol >> 8) & 0x7f)) / 100;
2245 		center = (left + right) >> 1;
2246 
2247 		chn_setvolume_multi(c, SND_VOL_C_MASTER, left, right, center);
2248 	}
2249 
2250 	if (c->feederflags & (1 << FEEDER_EQ)) {
2251 		struct pcm_feeder *f;
2252 		int treble, bass, state;
2253 
2254 		/* CHN_UNLOCK(c); */
2255 		treble = mix_get(m, SOUND_MIXER_TREBLE);
2256 		bass = mix_get(m, SOUND_MIXER_BASS);
2257 		/* CHN_LOCK(c); */
2258 
2259 		if (treble == -1)
2260 			treble = 50;
2261 		else
2262 			treble = ((treble & 0x7f) +
2263 			    ((treble >> 8) & 0x7f)) >> 1;
2264 
2265 		if (bass == -1)
2266 			bass = 50;
2267 		else
2268 			bass = ((bass & 0x7f) + ((bass >> 8) & 0x7f)) >> 1;
2269 
2270 		f = feeder_find(c, FEEDER_EQ);
2271 		if (f != NULL) {
2272 			if (FEEDER_SET(f, FEEDEQ_TREBLE, treble) != 0)
2273 				device_printf(c->dev,
2274 				    "EQ: Failed to set treble -- %d\n",
2275 				    treble);
2276 			if (FEEDER_SET(f, FEEDEQ_BASS, bass) != 0)
2277 				device_printf(c->dev,
2278 				    "EQ: Failed to set bass -- %d\n",
2279 				    bass);
2280 			if (FEEDER_SET(f, FEEDEQ_PREAMP, d->eqpreamp) != 0)
2281 				device_printf(c->dev,
2282 				    "EQ: Failed to set preamp -- %d\n",
2283 				    d->eqpreamp);
2284 			if (d->flags & SD_F_EQ_BYPASSED)
2285 				state = FEEDEQ_BYPASS;
2286 			else if (d->flags & SD_F_EQ_ENABLED)
2287 				state = FEEDEQ_ENABLE;
2288 			else
2289 				state = FEEDEQ_DISABLE;
2290 			if (FEEDER_SET(f, FEEDEQ_STATE, state) != 0)
2291 				device_printf(c->dev,
2292 				    "EQ: Failed to set state -- %d\n", state);
2293 		}
2294 	}
2295 }
2296 
2297 int
2298 chn_trigger(struct pcm_channel *c, int go)
2299 {
2300 	struct snddev_info *d = c->parentsnddev;
2301 	int ret;
2302 
2303 	CHN_LOCKASSERT(c);
2304 	if (!PCMTRIG_COMMON(go))
2305 		return (CHANNEL_TRIGGER(c->methods, c->devinfo, go));
2306 
2307 	if (go == c->trigger)
2308 		return (0);
2309 
2310 	if (snd_verbose > 3) {
2311 		device_printf(c->dev, "%s() %s: calling go=0x%08x , "
2312 		    "prev=0x%08x\n", __func__, c->name, go, c->trigger);
2313 	}
2314 
2315 	c->trigger = go;
2316 	ret = CHANNEL_TRIGGER(c->methods, c->devinfo, go);
2317 	if (ret != 0)
2318 		return (ret);
2319 
2320 	CHN_UNLOCK(c);
2321 	PCM_LOCK(d);
2322 	CHN_LOCK(c);
2323 
2324 	/*
2325 	 * Do nothing if another thread set a different trigger while we had
2326 	 * dropped the mutex.
2327 	 */
2328 	if (go != c->trigger) {
2329 		PCM_UNLOCK(d);
2330 		return (0);
2331 	}
2332 
2333 	/*
2334 	 * Use the SAFE variants to prevent inserting/removing an already
2335 	 * existing/missing element.
2336 	 */
2337 	switch (go) {
2338 	case PCMTRIG_START:
2339 		CHN_INSERT_HEAD_SAFE(d, c, channels.pcm.busy);
2340 		PCM_UNLOCK(d);
2341 		chn_syncstate(c);
2342 		break;
2343 	case PCMTRIG_STOP:
2344 	case PCMTRIG_ABORT:
2345 		CHN_REMOVE_SAFE(d, c, channels.pcm.busy);
2346 		PCM_UNLOCK(d);
2347 		break;
2348 	default:
2349 		PCM_UNLOCK(d);
2350 		break;
2351 	}
2352 
2353 	return (0);
2354 }
2355 
2356 /**
2357  * @brief Queries sound driver for sample-aligned hardware buffer pointer index
2358  *
2359  * This function obtains the hardware pointer location, then aligns it to
2360  * the current bytes-per-sample value before returning.  (E.g., a channel
2361  * running in 16 bit stereo mode would require 4 bytes per sample, so a
2362  * hwptr value ranging from 32-35 would be returned as 32.)
2363  *
2364  * @param c	PCM channel context
2365  * @returns 	sample-aligned hardware buffer pointer index
2366  */
2367 int
2368 chn_getptr(struct pcm_channel *c)
2369 {
2370 	int hwptr;
2371 
2372 	CHN_LOCKASSERT(c);
2373 	hwptr = (CHN_STARTED(c)) ? CHANNEL_GETPTR(c->methods, c->devinfo) : 0;
2374 	return (hwptr - (hwptr % sndbuf_getalign(c->bufhard)));
2375 }
2376 
2377 struct pcmchan_caps *
2378 chn_getcaps(struct pcm_channel *c)
2379 {
2380 	CHN_LOCKASSERT(c);
2381 	return CHANNEL_GETCAPS(c->methods, c->devinfo);
2382 }
2383 
2384 u_int32_t
2385 chn_getformats(struct pcm_channel *c)
2386 {
2387 	u_int32_t *fmtlist, fmts;
2388 	int i;
2389 
2390 	fmtlist = chn_getcaps(c)->fmtlist;
2391 	fmts = 0;
2392 	for (i = 0; fmtlist[i]; i++)
2393 		fmts |= fmtlist[i];
2394 
2395 	/* report software-supported formats */
2396 	if (!CHN_BITPERFECT(c) && report_soft_formats)
2397 		fmts |= AFMT_CONVERTIBLE;
2398 
2399 	return (AFMT_ENCODING(fmts));
2400 }
2401 
2402 int
2403 chn_notify(struct pcm_channel *c, u_int32_t flags)
2404 {
2405 	struct pcm_channel *ch;
2406 	struct pcmchan_caps *caps;
2407 	uint32_t bestformat, bestspeed, besthwformat, *vchanformat, *vchanrate;
2408 	uint32_t vpflags;
2409 	int dirty, err, run, nrun;
2410 
2411 	CHN_LOCKASSERT(c);
2412 
2413 	if (CHN_EMPTY(c, children))
2414 		return (ENODEV);
2415 
2416 	err = 0;
2417 
2418 	/*
2419 	 * If the hwchan is running, we can't change its rate, format or
2420 	 * blocksize
2421 	 */
2422 	run = (CHN_STARTED(c)) ? 1 : 0;
2423 	if (run)
2424 		flags &= CHN_N_VOLUME | CHN_N_TRIGGER;
2425 
2426 	if (flags & CHN_N_RATE) {
2427 		/*
2428 		 * XXX I'll make good use of this someday.
2429 		 *     However this is currently being superseded by
2430 		 *     the availability of CHN_F_VCHAN_DYNAMIC.
2431 		 */
2432 	}
2433 
2434 	if (flags & CHN_N_FORMAT) {
2435 		/*
2436 		 * XXX I'll make good use of this someday.
2437 		 *     However this is currently being superseded by
2438 		 *     the availability of CHN_F_VCHAN_DYNAMIC.
2439 		 */
2440 	}
2441 
2442 	if (flags & CHN_N_VOLUME) {
2443 		/*
2444 		 * XXX I'll make good use of this someday, though
2445 		 *     soft volume control is currently pretty much
2446 		 *     integrated.
2447 		 */
2448 	}
2449 
2450 	if (flags & CHN_N_BLOCKSIZE) {
2451 		/*
2452 		 * Set to default latency profile
2453 		 */
2454 		chn_setlatency(c, chn_latency);
2455 	}
2456 
2457 	if ((flags & CHN_N_TRIGGER) && !(c->flags & CHN_F_VCHAN_DYNAMIC)) {
2458 		nrun = CHN_EMPTY(c, children.busy) ? 0 : 1;
2459 		if (nrun && !run)
2460 			err = chn_start(c, 1);
2461 		if (!nrun && run)
2462 			chn_abort(c);
2463 		flags &= ~CHN_N_TRIGGER;
2464 	}
2465 
2466 	if (flags & CHN_N_TRIGGER) {
2467 		if (c->direction == PCMDIR_PLAY) {
2468 			vchanformat = &c->parentsnddev->pvchanformat;
2469 			vchanrate = &c->parentsnddev->pvchanrate;
2470 		} else {
2471 			vchanformat = &c->parentsnddev->rvchanformat;
2472 			vchanrate = &c->parentsnddev->rvchanrate;
2473 		}
2474 
2475 		/* Dynamic Virtual Channel */
2476 		if (!(c->flags & CHN_F_VCHAN_ADAPTIVE)) {
2477 			bestformat = *vchanformat;
2478 			bestspeed = *vchanrate;
2479 		} else {
2480 			bestformat = 0;
2481 			bestspeed = 0;
2482 		}
2483 
2484 		besthwformat = 0;
2485 		nrun = 0;
2486 		caps = chn_getcaps(c);
2487 		dirty = 0;
2488 		vpflags = 0;
2489 
2490 		CHN_FOREACH(ch, c, children.busy) {
2491 			CHN_LOCK(ch);
2492 			if ((ch->format & AFMT_PASSTHROUGH) &&
2493 			    snd_fmtvalid(ch->format, caps->fmtlist)) {
2494 				bestformat = ch->format;
2495 				bestspeed = ch->speed;
2496 				CHN_UNLOCK(ch);
2497 				vpflags = CHN_F_PASSTHROUGH;
2498 				nrun++;
2499 				break;
2500 			}
2501 			if ((ch->flags & CHN_F_EXCLUSIVE) && vpflags == 0) {
2502 				if (c->flags & CHN_F_VCHAN_ADAPTIVE) {
2503 					bestspeed = ch->speed;
2504 					RANGE(bestspeed, caps->minspeed,
2505 					    caps->maxspeed);
2506 					besthwformat = snd_fmtbest(ch->format,
2507 					    caps->fmtlist);
2508 					if (besthwformat != 0)
2509 						bestformat = besthwformat;
2510 				}
2511 				CHN_UNLOCK(ch);
2512 				vpflags = CHN_F_EXCLUSIVE;
2513 				nrun++;
2514 				continue;
2515 			}
2516 			if (!(c->flags & CHN_F_VCHAN_ADAPTIVE) ||
2517 			    vpflags != 0) {
2518 				CHN_UNLOCK(ch);
2519 				nrun++;
2520 				continue;
2521 			}
2522 			if (ch->speed > bestspeed) {
2523 				bestspeed = ch->speed;
2524 				RANGE(bestspeed, caps->minspeed,
2525 				    caps->maxspeed);
2526 			}
2527 			besthwformat = snd_fmtbest(ch->format, caps->fmtlist);
2528 			if (!(besthwformat & AFMT_VCHAN)) {
2529 				CHN_UNLOCK(ch);
2530 				nrun++;
2531 				continue;
2532 			}
2533 			if (AFMT_CHANNEL(besthwformat) >
2534 			    AFMT_CHANNEL(bestformat))
2535 				bestformat = besthwformat;
2536 			else if (AFMT_CHANNEL(besthwformat) ==
2537 			    AFMT_CHANNEL(bestformat) &&
2538 			    AFMT_BIT(besthwformat) > AFMT_BIT(bestformat))
2539 				bestformat = besthwformat;
2540 			CHN_UNLOCK(ch);
2541 			nrun++;
2542 		}
2543 
2544 		if (bestformat == 0)
2545 			bestformat = c->format;
2546 		if (bestspeed == 0)
2547 			bestspeed = c->speed;
2548 
2549 		if (bestformat != c->format || bestspeed != c->speed)
2550 			dirty = 1;
2551 
2552 		c->flags &= ~(CHN_F_PASSTHROUGH | CHN_F_EXCLUSIVE);
2553 		c->flags |= vpflags;
2554 
2555 		if (nrun && !run) {
2556 			if (dirty) {
2557 				bestspeed = CHANNEL_SETSPEED(c->methods,
2558 				    c->devinfo, bestspeed);
2559 				err = chn_reset(c, bestformat, bestspeed);
2560 			}
2561 			if (err == 0 && dirty) {
2562 				CHN_FOREACH(ch, c, children.busy) {
2563 					CHN_LOCK(ch);
2564 					if (VCHAN_SYNC_REQUIRED(ch))
2565 						vchan_sync(ch);
2566 					CHN_UNLOCK(ch);
2567 				}
2568 			}
2569 			if (err == 0) {
2570 				if (dirty)
2571 					c->flags |= CHN_F_DIRTY;
2572 				err = chn_start(c, 1);
2573 			}
2574 		}
2575 
2576 		if (nrun && run && dirty) {
2577 			chn_abort(c);
2578 			bestspeed = CHANNEL_SETSPEED(c->methods, c->devinfo,
2579 			    bestspeed);
2580 			err = chn_reset(c, bestformat, bestspeed);
2581 			if (err == 0) {
2582 				CHN_FOREACH(ch, c, children.busy) {
2583 					CHN_LOCK(ch);
2584 					if (VCHAN_SYNC_REQUIRED(ch))
2585 						vchan_sync(ch);
2586 					CHN_UNLOCK(ch);
2587 				}
2588 			}
2589 			if (err == 0) {
2590 				c->flags |= CHN_F_DIRTY;
2591 				err = chn_start(c, 1);
2592 			}
2593 		}
2594 
2595 		if (err == 0 && !(bestformat & AFMT_PASSTHROUGH) &&
2596 		    (bestformat & AFMT_VCHAN)) {
2597 			*vchanformat = bestformat;
2598 			*vchanrate = bestspeed;
2599 		}
2600 
2601 		if (!nrun && run) {
2602 			c->flags &= ~(CHN_F_PASSTHROUGH | CHN_F_EXCLUSIVE);
2603 			bestformat = *vchanformat;
2604 			bestspeed = *vchanrate;
2605 			chn_abort(c);
2606 			if (c->format != bestformat || c->speed != bestspeed)
2607 				chn_reset(c, bestformat, bestspeed);
2608 		}
2609 	}
2610 
2611 	return (err);
2612 }
2613 
2614 /**
2615  * @brief Fetch array of supported discrete sample rates
2616  *
2617  * Wrapper for CHANNEL_GETRATES.  Please see channel_if.m:getrates() for
2618  * detailed information.
2619  *
2620  * @note If the operation isn't supported, this function will just return 0
2621  *       (no rates in the array), and *rates will be set to NULL.  Callers
2622  *       should examine rates @b only if this function returns non-zero.
2623  *
2624  * @param c	pcm channel to examine
2625  * @param rates	pointer to array of integers; rate table will be recorded here
2626  *
2627  * @return number of rates in the array pointed to be @c rates
2628  */
2629 int
2630 chn_getrates(struct pcm_channel *c, int **rates)
2631 {
2632 	KASSERT(rates != NULL, ("rates is null"));
2633 	CHN_LOCKASSERT(c);
2634 	return CHANNEL_GETRATES(c->methods, c->devinfo, rates);
2635 }
2636 
2637 /**
2638  * @brief Remove channel from a sync group, if there is one.
2639  *
2640  * This function is initially intended for the following conditions:
2641  *   - Starting a syncgroup (@c SNDCTL_DSP_SYNCSTART ioctl)
2642  *   - Closing a device.  (A channel can't be destroyed if it's still in use.)
2643  *
2644  * @note Before calling this function, the syncgroup list mutex must be
2645  * held.  (Consider pcm_channel::sm protected by the SG list mutex
2646  * whether @c c is locked or not.)
2647  *
2648  * @param c	channel device to be started or closed
2649  * @returns	If this channel was the only member of a group, the group ID
2650  * 		is returned to the caller so that the caller can release it
2651  * 		via free_unr() after giving up the syncgroup lock.  Else it
2652  * 		returns 0.
2653  */
2654 int
2655 chn_syncdestroy(struct pcm_channel *c)
2656 {
2657 	struct pcmchan_syncmember *sm;
2658 	struct pcmchan_syncgroup *sg;
2659 	int sg_id;
2660 
2661 	sg_id = 0;
2662 
2663 	PCM_SG_LOCKASSERT(MA_OWNED);
2664 
2665 	if (c->sm != NULL) {
2666 		sm = c->sm;
2667 		sg = sm->parent;
2668 		c->sm = NULL;
2669 
2670 		KASSERT(sg != NULL, ("syncmember has null parent"));
2671 
2672 		SLIST_REMOVE(&sg->members, sm, pcmchan_syncmember, link);
2673 		free(sm, M_DEVBUF);
2674 
2675 		if (SLIST_EMPTY(&sg->members)) {
2676 			SLIST_REMOVE(&snd_pcm_syncgroups, sg, pcmchan_syncgroup, link);
2677 			sg_id = sg->id;
2678 			free(sg, M_DEVBUF);
2679 		}
2680 	}
2681 
2682 	return sg_id;
2683 }
2684 
2685 #ifdef OSSV4_EXPERIMENT
2686 int
2687 chn_getpeaks(struct pcm_channel *c, int *lpeak, int *rpeak)
2688 {
2689 	CHN_LOCKASSERT(c);
2690 	return CHANNEL_GETPEAKS(c->methods, c->devinfo, lpeak, rpeak);
2691 }
2692 #endif
2693