xref: /freebsd/sys/dev/sound/pcm/feeder_chain.c (revision e1bbaa71d62c8681a576f9f5bedf475c7541bd35)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2008-2009 Ariff Abdullah <ariff@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #ifdef HAVE_KERNEL_OPTION_HEADERS
30 #include "opt_snd.h"
31 #endif
32 
33 #include <dev/sound/pcm/sound.h>
34 
35 #include "feeder_if.h"
36 
37 /* chain state */
38 struct feeder_chain_state {
39 	uint32_t afmt;				/* audio format */
40 	uint32_t rate;				/* sampling rate */
41 	struct pcmchan_matrix *matrix;		/* matrix map */
42 };
43 
44 /*
45  * chain descriptor that will be passed around from the beginning until the
46  * end of chain process.
47  */
48 struct feeder_chain_desc {
49 	struct feeder_chain_state origin;	/* original state */
50 	struct feeder_chain_state current;	/* current state */
51 	struct feeder_chain_state target;	/* target state */
52 	struct pcm_feederdesc desc;		/* feeder descriptor */
53 	uint32_t afmt_ne;			/* preferred native endian */
54 	int mode;				/* chain mode */
55 	int use_eq;				/* need EQ? */
56 	int use_matrix;				/* need channel matrixing? */
57 	int use_volume;				/* need softpcmvol? */
58 	int dummy;				/* dummy passthrough */
59 	int expensive;				/* possibly expensive */
60 };
61 
62 #define FEEDER_CHAIN_LEAN		0
63 #define FEEDER_CHAIN_16			1
64 #define FEEDER_CHAIN_32			2
65 #define FEEDER_CHAIN_MULTI		3
66 #define FEEDER_CHAIN_FULLMULTI		4
67 #define FEEDER_CHAIN_LAST		5
68 
69 #if defined(SND_FEEDER_FULL_MULTIFORMAT)
70 #define FEEDER_CHAIN_DEFAULT		FEEDER_CHAIN_FULLMULTI
71 #elif defined(SND_FEEDER_MULTIFORMAT)
72 #define FEEDER_CHAIN_DEFAULT		FEEDER_CHAIN_MULTI
73 #else
74 #define FEEDER_CHAIN_DEFAULT		FEEDER_CHAIN_LEAN
75 #endif
76 
77 /*
78  * List of preferred formats that might be required during
79  * processing. It will be decided through snd_fmtbest().
80  */
81 
82 /* 'Lean' mode, signed 16 or 32 bit native endian. */
83 static uint32_t feeder_chain_formats_lean[] = {
84 	AFMT_S16_NE, AFMT_S32_NE,
85 	0
86 };
87 
88 /* Force everything to signed 16 bit native endian. */
89 static uint32_t feeder_chain_formats_16[] = {
90 	AFMT_S16_NE,
91 	0
92 };
93 
94 /* Force everything to signed 32 bit native endian. */
95 static uint32_t feeder_chain_formats_32[] = {
96 	AFMT_S32_NE,
97 	0
98 };
99 
100 /* Multiple choices, all except 8 bit. */
101 static uint32_t feeder_chain_formats_multi[] = {
102 	AFMT_S16_LE, AFMT_S16_BE, AFMT_U16_LE, AFMT_U16_BE,
103 	AFMT_S24_LE, AFMT_S24_BE, AFMT_U24_LE, AFMT_U24_BE,
104 	AFMT_S32_LE, AFMT_S32_BE, AFMT_U32_LE, AFMT_U32_BE,
105 	AFMT_F32_LE, AFMT_F32_BE,
106 	0
107 };
108 
109 /* Everything that is convertible. */
110 static uint32_t feeder_chain_formats_fullmulti[] = {
111 	AFMT_S8, AFMT_U8,
112 	AFMT_S16_LE, AFMT_S16_BE, AFMT_U16_LE, AFMT_U16_BE,
113 	AFMT_S24_LE, AFMT_S24_BE, AFMT_U24_LE, AFMT_U24_BE,
114 	AFMT_S32_LE, AFMT_S32_BE, AFMT_U32_LE, AFMT_U32_BE,
115 	AFMT_F32_LE, AFMT_F32_BE,
116 	0
117 };
118 
119 static uint32_t *feeder_chain_formats[FEEDER_CHAIN_LAST] = {
120 	[FEEDER_CHAIN_LEAN]      = feeder_chain_formats_lean,
121 	[FEEDER_CHAIN_16]        = feeder_chain_formats_16,
122 	[FEEDER_CHAIN_32]        = feeder_chain_formats_32,
123 	[FEEDER_CHAIN_MULTI]     = feeder_chain_formats_multi,
124 	[FEEDER_CHAIN_FULLMULTI] = feeder_chain_formats_fullmulti
125 };
126 
127 static int feeder_chain_mode = FEEDER_CHAIN_DEFAULT;
128 
129 #if defined(_KERNEL) && defined(SND_DEBUG) && defined(SND_FEEDER_FULL_MULTIFORMAT)
130 SYSCTL_INT(_hw_snd, OID_AUTO, feeder_chain_mode, CTLFLAG_RWTUN,
131     &feeder_chain_mode, 0,
132     "feeder chain mode "
133     "(0=lean, 1=16bit, 2=32bit, 3=multiformat, 4=fullmultiformat)");
134 #endif
135 
136 /*
137  * feeder_build_format(): Chain any format converter.
138  */
139 static int
feeder_build_format(struct pcm_channel * c,struct feeder_chain_desc * cdesc)140 feeder_build_format(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
141 {
142 	struct feeder_class *fc;
143 	struct pcm_feederdesc *desc;
144 	int ret;
145 
146 	desc = &(cdesc->desc);
147 	desc->type = FEEDER_FORMAT;
148 	desc->in = 0;
149 	desc->out = 0;
150 	desc->flags = 0;
151 
152 	fc = feeder_getclass(desc);
153 	if (fc == NULL) {
154 		device_printf(c->dev,
155 		    "%s(): can't find feeder_format\n", __func__);
156 		return (ENOTSUP);
157 	}
158 
159 	desc->in = cdesc->current.afmt;
160 	desc->out = cdesc->target.afmt;
161 
162 	ret = feeder_add(c, fc, desc);
163 	if (ret != 0) {
164 		device_printf(c->dev,
165 		    "%s(): can't add feeder_format\n", __func__);
166 		return (ret);
167 	}
168 
169 	c->feederflags |= 1 << FEEDER_FORMAT;
170 
171 	cdesc->current.afmt = cdesc->target.afmt;
172 
173 	return (0);
174 }
175 
176 /*
177  * feeder_build_formatne(): Chain format converter that suite best for native
178  *                          endian format.
179  */
180 static int
feeder_build_formatne(struct pcm_channel * c,struct feeder_chain_desc * cdesc)181 feeder_build_formatne(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
182 {
183 	struct feeder_chain_state otarget;
184 	int ret;
185 
186 	if (cdesc->afmt_ne == 0 ||
187 	    AFMT_ENCODING(cdesc->current.afmt) == cdesc->afmt_ne)
188 		return (0);
189 
190 	otarget = cdesc->target;
191 	cdesc->target = cdesc->current;
192 	cdesc->target.afmt = SND_FORMAT(cdesc->afmt_ne,
193 	    cdesc->current.matrix->channels, cdesc->current.matrix->ext);
194 
195 	ret = feeder_build_format(c, cdesc);
196 	if (ret != 0)
197 		return (ret);
198 
199 	cdesc->target = otarget;
200 
201 	return (0);
202 }
203 
204 /*
205  * feeder_build_rate(): Chain sample rate converter.
206  */
207 static int
feeder_build_rate(struct pcm_channel * c,struct feeder_chain_desc * cdesc)208 feeder_build_rate(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
209 {
210 	struct feeder_class *fc;
211 	struct pcm_feeder *f;
212 	struct pcm_feederdesc *desc;
213 	int ret;
214 
215 	ret = feeder_build_formatne(c, cdesc);
216 	if (ret != 0)
217 		return (ret);
218 
219 	desc = &(cdesc->desc);
220 	desc->type = FEEDER_RATE;
221 	desc->in = 0;
222 	desc->out = 0;
223 	desc->flags = 0;
224 
225 	fc = feeder_getclass(desc);
226 	if (fc == NULL) {
227 		device_printf(c->dev,
228 		    "%s(): can't find feeder_rate\n", __func__);
229 		return (ENOTSUP);
230 	}
231 
232 	desc->in = cdesc->current.afmt;
233 	desc->out = desc->in;
234 
235 	ret = feeder_add(c, fc, desc);
236 	if (ret != 0) {
237 		device_printf(c->dev,
238 		    "%s(): can't add feeder_rate\n", __func__);
239 		return (ret);
240 	}
241 
242 	f = c->feeder;
243 
244 	/*
245 	 * If in 'dummy' mode (possibly due to passthrough mode), set the
246 	 * conversion quality to the lowest possible (should be fastest) since
247 	 * listener won't be hearing anything. Theoretically we can just
248 	 * disable it, but that will cause weird runtime behaviour:
249 	 * application appear to play something that is either too fast or too
250 	 * slow.
251 	 */
252 	if (cdesc->dummy != 0) {
253 		ret = FEEDER_SET(f, FEEDRATE_QUALITY, 0);
254 		if (ret != 0) {
255 			device_printf(c->dev,
256 			    "%s(): can't set resampling quality\n", __func__);
257 			return (ret);
258 		}
259 	}
260 
261 	ret = FEEDER_SET(f, FEEDRATE_SRC, cdesc->current.rate);
262 	if (ret != 0) {
263 		device_printf(c->dev,
264 		    "%s(): can't set source rate\n", __func__);
265 		return (ret);
266 	}
267 
268 	ret = FEEDER_SET(f, FEEDRATE_DST, cdesc->target.rate);
269 	if (ret != 0) {
270 		device_printf(c->dev,
271 		    "%s(): can't set destination rate\n", __func__);
272 		return (ret);
273 	}
274 
275 	c->feederflags |= 1 << FEEDER_RATE;
276 
277 	cdesc->current.rate = cdesc->target.rate;
278 
279 	return (0);
280 }
281 
282 /*
283  * feeder_build_matrix(): Chain channel matrixing converter.
284  */
285 static int
feeder_build_matrix(struct pcm_channel * c,struct feeder_chain_desc * cdesc)286 feeder_build_matrix(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
287 {
288 	struct feeder_class *fc;
289 	struct pcm_feeder *f;
290 	struct pcm_feederdesc *desc;
291 	int ret;
292 
293 	ret = feeder_build_formatne(c, cdesc);
294 	if (ret != 0)
295 		return (ret);
296 
297 	desc = &(cdesc->desc);
298 	desc->type = FEEDER_MATRIX;
299 	desc->in = 0;
300 	desc->out = 0;
301 	desc->flags = 0;
302 
303 	fc = feeder_getclass(desc);
304 	if (fc == NULL) {
305 		device_printf(c->dev,
306 		    "%s(): can't find feeder_matrix\n", __func__);
307 		return (ENOTSUP);
308 	}
309 
310 	desc->in = cdesc->current.afmt;
311 	desc->out = SND_FORMAT(cdesc->current.afmt,
312 	    cdesc->target.matrix->channels, cdesc->target.matrix->ext);
313 
314 	ret = feeder_add(c, fc, desc);
315 	if (ret != 0) {
316 		device_printf(c->dev,
317 		    "%s(): can't add feeder_matrix\n", __func__);
318 		return (ret);
319 	}
320 
321 	f = c->feeder;
322 	ret = feeder_matrix_setup(f, cdesc->current.matrix,
323 	    cdesc->target.matrix);
324 	if (ret != 0) {
325 		device_printf(c->dev,
326 		    "%s(): feeder_matrix_setup() failed\n", __func__);
327 		return (ret);
328 	}
329 
330 	c->feederflags |= 1 << FEEDER_MATRIX;
331 
332 	cdesc->current.afmt = desc->out;
333 	cdesc->current.matrix = cdesc->target.matrix;
334 	cdesc->use_matrix = 0;
335 
336 	return (0);
337 }
338 
339 /*
340  * feeder_build_volume(): Chain soft volume.
341  */
342 static int
feeder_build_volume(struct pcm_channel * c,struct feeder_chain_desc * cdesc)343 feeder_build_volume(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
344 {
345 	struct feeder_class *fc;
346 	struct pcm_feeder *f;
347 	struct pcm_feederdesc *desc;
348 	int ret;
349 
350 	ret = feeder_build_formatne(c, cdesc);
351 	if (ret != 0)
352 		return (ret);
353 
354 	desc = &(cdesc->desc);
355 	desc->type = FEEDER_VOLUME;
356 	desc->in = 0;
357 	desc->out = 0;
358 	desc->flags = 0;
359 
360 	fc = feeder_getclass(desc);
361 	if (fc == NULL) {
362 		device_printf(c->dev,
363 		    "%s(): can't find feeder_volume\n", __func__);
364 		return (ENOTSUP);
365 	}
366 
367 	desc->in = cdesc->current.afmt;
368 	desc->out = desc->in;
369 
370 	ret = feeder_add(c, fc, desc);
371 	if (ret != 0) {
372 		device_printf(c->dev,
373 		    "%s(): can't add feeder_volume\n", __func__);
374 		return (ret);
375 	}
376 
377 	f = c->feeder;
378 
379 	/*
380 	 * If in 'dummy' mode (possibly due to passthrough mode), set BYPASS
381 	 * mode since listener won't be hearing anything. Theoretically we can
382 	 * just disable it, but that will confuse volume per channel mixer.
383 	 */
384 	if (cdesc->dummy != 0) {
385 		ret = FEEDER_SET(f, FEEDVOLUME_STATE, FEEDVOLUME_BYPASS);
386 		if (ret != 0) {
387 			device_printf(c->dev,
388 			    "%s(): can't set volume bypass\n", __func__);
389 			return (ret);
390 		}
391 	}
392 
393 	ret = feeder_volume_apply_matrix(f, cdesc->current.matrix);
394 	if (ret != 0) {
395 		device_printf(c->dev,
396 		    "%s(): feeder_volume_apply_matrix() failed\n", __func__);
397 		return (ret);
398 	}
399 
400 	c->feederflags |= 1 << FEEDER_VOLUME;
401 
402 	cdesc->use_volume = 0;
403 
404 	return (0);
405 }
406 
407 /*
408  * feeder_build_eq(): Chain parametric software equalizer.
409  */
410 static int
feeder_build_eq(struct pcm_channel * c,struct feeder_chain_desc * cdesc)411 feeder_build_eq(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
412 {
413 	struct feeder_class *fc;
414 	struct pcm_feeder *f;
415 	struct pcm_feederdesc *desc;
416 	int ret;
417 
418 	ret = feeder_build_formatne(c, cdesc);
419 	if (ret != 0)
420 		return (ret);
421 
422 	desc = &(cdesc->desc);
423 	desc->type = FEEDER_EQ;
424 	desc->in = 0;
425 	desc->out = 0;
426 	desc->flags = 0;
427 
428 	fc = feeder_getclass(desc);
429 	if (fc == NULL) {
430 		device_printf(c->dev,
431 		    "%s(): can't find feeder_eq\n", __func__);
432 		return (ENOTSUP);
433 	}
434 
435 	desc->in = cdesc->current.afmt;
436 	desc->out = desc->in;
437 
438 	ret = feeder_add(c, fc, desc);
439 	if (ret != 0) {
440 		device_printf(c->dev,
441 		    "%s(): can't add feeder_eq\n", __func__);
442 		return (ret);
443 	}
444 
445 	f = c->feeder;
446 
447 	ret = FEEDER_SET(f, FEEDEQ_RATE, cdesc->current.rate);
448 	if (ret != 0) {
449 		device_printf(c->dev,
450 		    "%s(): can't set rate on feeder_eq\n", __func__);
451 		return (ret);
452 	}
453 
454 	c->feederflags |= 1 << FEEDER_EQ;
455 
456 	cdesc->use_eq = 0;
457 
458 	return (0);
459 }
460 
461 /*
462  * feeder_build_root(): Chain root feeder, the top, father of all.
463  */
464 static int
feeder_build_root(struct pcm_channel * c,struct feeder_chain_desc * cdesc)465 feeder_build_root(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
466 {
467 	struct feeder_class *fc;
468 	int ret;
469 
470 	fc = feeder_getclass(NULL);
471 	if (fc == NULL) {
472 		device_printf(c->dev,
473 		    "%s(): can't find feeder_root\n", __func__);
474 		return (ENOTSUP);
475 	}
476 
477 	ret = feeder_add(c, fc, NULL);
478 	if (ret != 0) {
479 		device_printf(c->dev,
480 		    "%s(): can't add feeder_root\n", __func__);
481 		return (ret);
482 	}
483 
484 	c->feederflags |= 1 << FEEDER_ROOT;
485 
486 	c->feeder->desc->in = cdesc->current.afmt;
487 	c->feeder->desc->out = cdesc->current.afmt;
488 
489 	return (0);
490 }
491 
492 /*
493  * feeder_build_mixer(): Chain software mixer for virtual channels.
494  */
495 static int
feeder_build_mixer(struct pcm_channel * c,struct feeder_chain_desc * cdesc)496 feeder_build_mixer(struct pcm_channel *c, struct feeder_chain_desc *cdesc)
497 {
498 	struct feeder_class *fc;
499 	struct pcm_feederdesc *desc;
500 	int ret;
501 
502 	desc = &(cdesc->desc);
503 	desc->type = FEEDER_MIXER;
504 	desc->in = 0;
505 	desc->out = 0;
506 	desc->flags = 0;
507 
508 	fc = feeder_getclass(desc);
509 	if (fc == NULL) {
510 		device_printf(c->dev,
511 		    "%s(): can't find feeder_mixer\n", __func__);
512 		return (ENOTSUP);
513 	}
514 
515 	desc->in = cdesc->current.afmt;
516 	desc->out = desc->in;
517 
518 	ret = feeder_add(c, fc, desc);
519 	if (ret != 0) {
520 		device_printf(c->dev,
521 		    "%s(): can't add feeder_mixer\n", __func__);
522 		return (ret);
523 	}
524 
525 	c->feederflags |= 1 << FEEDER_MIXER;
526 
527 	return (0);
528 }
529 
530 /* Macrosses to ease our job doing stuffs later. */
531 #define FEEDER_BW(c, t)		((c)->t.matrix->channels * (c)->t.rate)
532 
533 #define FEEDRATE_UP(c)		((c)->target.rate > (c)->current.rate)
534 #define FEEDRATE_DOWN(c)	((c)->target.rate < (c)->current.rate)
535 #define FEEDRATE_REQUIRED(c)	(FEEDRATE_UP(c) || FEEDRATE_DOWN(c))
536 
537 #define FEEDMATRIX_UP(c)	((c)->target.matrix->channels >		\
538 				 (c)->current.matrix->channels)
539 #define FEEDMATRIX_DOWN(c)	((c)->target.matrix->channels <		\
540 				 (c)->current.matrix->channels)
541 #define FEEDMATRIX_REQUIRED(c)	(FEEDMATRIX_UP(c) ||			\
542 				 FEEDMATRIX_DOWN(c) || (c)->use_matrix != 0)
543 
544 #define FEEDFORMAT_REQUIRED(c)	(AFMT_ENCODING((c)->current.afmt) !=	\
545 				 AFMT_ENCODING((c)->target.afmt))
546 
547 #define FEEDVOLUME_REQUIRED(c)	((c)->use_volume != 0)
548 
549 #define FEEDEQ_VALIDRATE(c, t)	(feeder_eq_validrate((c)->t.rate) != 0)
550 #define FEEDEQ_ECONOMY(c)	(FEEDER_BW(c, current) < FEEDER_BW(c, target))
551 #define FEEDEQ_REQUIRED(c)	((c)->use_eq != 0 &&			\
552 				 FEEDEQ_VALIDRATE(c, current))
553 
554 #define FEEDFORMAT_NE_REQUIRED(c)					\
555 	((c)->afmt_ne != AFMT_S32_NE &&					\
556 	(((c)->mode == FEEDER_CHAIN_16 &&				\
557 	AFMT_ENCODING((c)->current.afmt) != AFMT_S16_NE) ||		\
558 	((c)->mode == FEEDER_CHAIN_32 &&				\
559 	AFMT_ENCODING((c)->current.afmt) != AFMT_S32_NE) ||		\
560 	(c)->mode == FEEDER_CHAIN_FULLMULTI ||				\
561 	((c)->mode == FEEDER_CHAIN_MULTI &&				\
562 	((c)->current.afmt & AFMT_8BIT)) ||				\
563 	((c)->mode == FEEDER_CHAIN_LEAN &&				\
564 	!((c)->current.afmt & (AFMT_S16_NE | AFMT_S32_NE)))))
565 
566 static void
feeder_default_matrix(struct pcmchan_matrix * m,uint32_t fmt,int id)567 feeder_default_matrix(struct pcmchan_matrix *m, uint32_t fmt, int id)
568 {
569 	int x;
570 
571 	memset(m, 0, sizeof(*m));
572 
573 	m->id = id;
574 	m->channels = AFMT_CHANNEL(fmt);
575 	m->ext = AFMT_EXTCHANNEL(fmt);
576 	for (x = 0; x != SND_CHN_T_MAX; x++)
577 		m->offset[x] = -1;
578 }
579 
580 int
feeder_chain(struct pcm_channel * c)581 feeder_chain(struct pcm_channel *c)
582 {
583 	struct snddev_info *d;
584 	struct pcmchan_caps *caps;
585 	struct feeder_chain_desc cdesc;
586 	struct pcmchan_matrix *hwmatrix, *softmatrix;
587 	uint32_t hwfmt, softfmt;
588 	int ret;
589 
590 	CHN_LOCKASSERT(c);
591 
592 	/* Remove everything first. */
593 	feeder_remove(c);
594 
595 	KASSERT(c->feeder == NULL, ("feeder chain not empty"));
596 
597 	/* clear and populate chain descriptor. */
598 	bzero(&cdesc, sizeof(cdesc));
599 
600 	switch (feeder_chain_mode) {
601 	case FEEDER_CHAIN_LEAN:
602 	case FEEDER_CHAIN_16:
603 	case FEEDER_CHAIN_32:
604 #if defined(SND_FEEDER_MULTIFORMAT) || defined(SND_FEEDER_FULL_MULTIFORMAT)
605 	case FEEDER_CHAIN_MULTI:
606 #endif
607 #if defined(SND_FEEDER_FULL_MULTIFORMAT)
608 	case FEEDER_CHAIN_FULLMULTI:
609 #endif
610 		break;
611 	default:
612 		feeder_chain_mode = FEEDER_CHAIN_DEFAULT;
613 		break;
614 	}
615 
616 	cdesc.mode = feeder_chain_mode;
617 	cdesc.expensive = 1;	/* XXX faster.. */
618 
619 #define VCHAN_PASSTHROUGH(c)	(((c)->flags & (CHN_F_VIRTUAL |		\
620 				 CHN_F_PASSTHROUGH)) ==			\
621 				 (CHN_F_VIRTUAL | CHN_F_PASSTHROUGH))
622 
623 	/* Get the best possible hardware format. */
624 	if (VCHAN_PASSTHROUGH(c))
625 		hwfmt = c->parentchannel->format;
626 	else {
627 		caps = chn_getcaps(c);
628 		if (caps == NULL || caps->fmtlist == NULL) {
629 			device_printf(c->dev,
630 			    "%s(): failed to get channel caps\n", __func__);
631 			return (ENODEV);
632 		}
633 
634 		if ((c->format & AFMT_PASSTHROUGH) &&
635 		    !snd_fmtvalid(c->format, caps->fmtlist))
636 			return (ENODEV);
637 
638 		hwfmt = snd_fmtbest(c->format, caps->fmtlist);
639 		if (hwfmt == 0 || !snd_fmtvalid(hwfmt, caps->fmtlist)) {
640 			device_printf(c->dev,
641 			    "%s(): invalid hardware format 0x%08x\n",
642 			    __func__, hwfmt);
643 			{
644 				int i;
645 				for (i = 0; caps->fmtlist[i] != 0; i++)
646 					printf("0x%08x\n", caps->fmtlist[i]);
647 				printf("Req: 0x%08x\n", c->format);
648 			}
649 			return (ENODEV);
650 		}
651 	}
652 
653 	/*
654 	 * The 'hardware' possibly have different interpretation of channel
655 	 * matrixing, so get it first .....
656 	 */
657 	hwmatrix = CHANNEL_GETMATRIX(c->methods, c->devinfo, hwfmt);
658 	if (hwmatrix == NULL) {
659 		/* setup a default matrix */
660 		hwmatrix = &c->matrix_scratch;
661 		feeder_default_matrix(hwmatrix, hwfmt,
662 		    SND_CHN_MATRIX_UNKNOWN);
663 	}
664 	/* ..... and rebuild hwfmt. */
665 	hwfmt = SND_FORMAT(hwfmt, hwmatrix->channels, hwmatrix->ext);
666 
667 	/* Reset and rebuild default channel format/matrix map. */
668 	softfmt = c->format;
669 	softmatrix = &c->matrix;
670 	if (softmatrix->channels != AFMT_CHANNEL(softfmt) ||
671 	    softmatrix->ext != AFMT_EXTCHANNEL(softfmt)) {
672 		softmatrix = feeder_matrix_format_map(softfmt);
673 		if (softmatrix == NULL) {
674 			/* setup a default matrix */
675 		  	softmatrix = &c->matrix;
676 			feeder_default_matrix(softmatrix, softfmt,
677 			    SND_CHN_MATRIX_PCMCHANNEL);
678 		} else {
679 			c->matrix = *softmatrix;
680 			c->matrix.id = SND_CHN_MATRIX_PCMCHANNEL;
681 		}
682 	}
683 	softfmt = SND_FORMAT(softfmt, softmatrix->channels, softmatrix->ext);
684 	if (softfmt != c->format)
685 		device_printf(c->dev,
686 		    "%s(): WARNING: %s Soft format 0x%08x -> 0x%08x\n",
687 		    __func__, CHN_DIRSTR(c), c->format, softfmt);
688 
689 	/*
690 	 * PLAY and REC are opposite.
691 	 */
692 	if (c->direction == PCMDIR_PLAY) {
693 		cdesc.origin.afmt    = softfmt;
694 		cdesc.origin.matrix  = softmatrix;
695 		cdesc.origin.rate    = c->speed;
696 		cdesc.target.afmt    = hwfmt;
697 		cdesc.target.matrix  = hwmatrix;
698 		cdesc.target.rate    = sndbuf_getspd(c->bufhard);
699 	} else {
700 		cdesc.origin.afmt    = hwfmt;
701 		cdesc.origin.matrix  = hwmatrix;
702 		cdesc.origin.rate    = sndbuf_getspd(c->bufhard);
703 		cdesc.target.afmt    = softfmt;
704 		cdesc.target.matrix  = softmatrix;
705 		cdesc.target.rate    = c->speed;
706 	}
707 
708 	d = c->parentsnddev;
709 
710 	/*
711 	 * If channel is in bitperfect or passthrough mode, make it appear
712 	 * that 'origin' and 'target' identical, skipping mostly chain
713 	 * procedures.
714 	 */
715 	if (CHN_BITPERFECT(c) || (c->format & AFMT_PASSTHROUGH)) {
716 		if (c->direction == PCMDIR_PLAY)
717 			cdesc.origin = cdesc.target;
718 		else
719 			cdesc.target = cdesc.origin;
720 		c->format = cdesc.target.afmt;
721 		c->speed  = cdesc.target.rate;
722 	} else {
723 		/*
724 		 * Bail out early if we do not support either of those formats.
725 		 */
726 		if ((cdesc.origin.afmt & AFMT_CONVERTIBLE) == 0 ||
727 		    (cdesc.target.afmt & AFMT_CONVERTIBLE) == 0) {
728 			device_printf(c->dev,
729 			    "%s(): unsupported formats: in=0x%08x, out=0x%08x\n",
730 			    __func__, cdesc.origin.afmt, cdesc.target.afmt);
731 			return (ENODEV);
732 		}
733 
734 		/* hwfmt is not convertible, so 'dummy' it. */
735 		if (hwfmt & AFMT_PASSTHROUGH)
736 			cdesc.dummy = 1;
737 
738 		if ((softfmt & AFMT_CONVERTIBLE) &&
739 		    (((d->flags & SD_F_VPC) && !(c->flags & CHN_F_HAS_VCHAN)) ||
740 		    (!(d->flags & SD_F_VPC) && (d->flags & SD_F_SOFTPCMVOL) &&
741 		    !(c->flags & CHN_F_VIRTUAL))))
742 			cdesc.use_volume = 1;
743 
744 		if (feeder_matrix_compare(cdesc.origin.matrix,
745 		    cdesc.target.matrix) != 0)
746 			cdesc.use_matrix = 1;
747 
748 		/* Soft EQ only applicable for PLAY. */
749 		if (cdesc.dummy == 0 &&
750 		    c->direction == PCMDIR_PLAY && (d->flags & SD_F_EQ) &&
751 		    (((d->flags & SD_F_EQ_PC) &&
752 		    !(c->flags & CHN_F_HAS_VCHAN)) ||
753 		    (!(d->flags & SD_F_EQ_PC) && !(c->flags & CHN_F_VIRTUAL))))
754 			cdesc.use_eq = 1;
755 
756 		if (FEEDFORMAT_NE_REQUIRED(&cdesc)) {
757 			cdesc.afmt_ne =
758 			    (cdesc.dummy != 0) ?
759 			    snd_fmtbest(AFMT_ENCODING(softfmt),
760 			    feeder_chain_formats[cdesc.mode]) :
761 			    snd_fmtbest(AFMT_ENCODING(cdesc.target.afmt),
762 			    feeder_chain_formats[cdesc.mode]);
763 			if (cdesc.afmt_ne == 0) {
764 				device_printf(c->dev,
765 				    "%s(): snd_fmtbest failed!\n", __func__);
766 				cdesc.afmt_ne =
767 				    (((cdesc.dummy != 0) ? softfmt :
768 				    cdesc.target.afmt) &
769 				    (AFMT_24BIT | AFMT_32BIT)) ?
770 				    AFMT_S32_NE : AFMT_S16_NE;
771 			}
772 		}
773 	}
774 
775 	cdesc.current = cdesc.origin;
776 
777 	/* Build everything. */
778 
779 	c->feederflags = 0;
780 
781 #define FEEDER_BUILD(t)	do {						\
782 	ret = feeder_build_##t(c, &cdesc);				\
783 	if (ret != 0)							\
784 		return (ret);						\
785 	} while (0)
786 
787 	if (!(c->flags & CHN_F_HAS_VCHAN) || c->direction == PCMDIR_REC)
788 		FEEDER_BUILD(root);
789 	else if (c->direction == PCMDIR_PLAY && (c->flags & CHN_F_HAS_VCHAN))
790 		FEEDER_BUILD(mixer);
791 	else
792 		return (ENOTSUP);
793 
794 	/*
795 	 * The basic idea is: The smaller the bandwidth, the cheaper the
796 	 * conversion process, with following constraints:-
797 	 *
798 	 * 1) Almost all feeders work best in 16/32 native endian.
799 	 * 2) Try to avoid 8bit feeders due to poor dynamic range.
800 	 * 3) Avoid volume, format, matrix and rate in BITPERFECT or
801 	 *    PASSTHROUGH mode.
802 	 * 4) Try putting volume before EQ or rate. Should help to
803 	 *    avoid/reduce possible clipping.
804 	 * 5) EQ require specific, valid rate, unless it allow sloppy
805 	 *    conversion.
806 	 */
807 	if (FEEDMATRIX_UP(&cdesc)) {
808 		if (FEEDEQ_REQUIRED(&cdesc) &&
809 		    (!FEEDEQ_VALIDRATE(&cdesc, target) ||
810 		    (cdesc.expensive == 0 && FEEDEQ_ECONOMY(&cdesc))))
811 			FEEDER_BUILD(eq);
812 		if (FEEDRATE_REQUIRED(&cdesc))
813 			FEEDER_BUILD(rate);
814 		FEEDER_BUILD(matrix);
815 		if (FEEDVOLUME_REQUIRED(&cdesc))
816 			FEEDER_BUILD(volume);
817 		if (FEEDEQ_REQUIRED(&cdesc))
818 			FEEDER_BUILD(eq);
819 	} else if (FEEDMATRIX_DOWN(&cdesc)) {
820 		FEEDER_BUILD(matrix);
821 		if (FEEDVOLUME_REQUIRED(&cdesc))
822 			FEEDER_BUILD(volume);
823 		if (FEEDEQ_REQUIRED(&cdesc) &&
824 		    (!FEEDEQ_VALIDRATE(&cdesc, target) ||
825 		    FEEDEQ_ECONOMY(&cdesc)))
826 			FEEDER_BUILD(eq);
827 		if (FEEDRATE_REQUIRED(&cdesc))
828 			FEEDER_BUILD(rate);
829 		if (FEEDEQ_REQUIRED(&cdesc))
830 			FEEDER_BUILD(eq);
831 	} else {
832 		if (FEEDRATE_DOWN(&cdesc)) {
833 			if (FEEDEQ_REQUIRED(&cdesc) &&
834 			    !FEEDEQ_VALIDRATE(&cdesc, target)) {
835 				if (FEEDVOLUME_REQUIRED(&cdesc))
836 					FEEDER_BUILD(volume);
837 				FEEDER_BUILD(eq);
838 			}
839 			FEEDER_BUILD(rate);
840 		}
841 		if (FEEDMATRIX_REQUIRED(&cdesc))
842 			FEEDER_BUILD(matrix);
843 		if (FEEDVOLUME_REQUIRED(&cdesc))
844 			FEEDER_BUILD(volume);
845 		if (FEEDRATE_UP(&cdesc)) {
846 			if (FEEDEQ_REQUIRED(&cdesc) &&
847 			    !FEEDEQ_VALIDRATE(&cdesc, target))
848 				FEEDER_BUILD(eq);
849 			FEEDER_BUILD(rate);
850 		}
851 		if (FEEDEQ_REQUIRED(&cdesc))
852 			FEEDER_BUILD(eq);
853 	}
854 
855 	if (FEEDFORMAT_REQUIRED(&cdesc))
856 		FEEDER_BUILD(format);
857 
858 	if (c->direction == PCMDIR_REC && (c->flags & CHN_F_HAS_VCHAN))
859 		FEEDER_BUILD(mixer);
860 
861 	sndbuf_setfmt(c->bufsoft, c->format);
862 	sndbuf_setspd(c->bufsoft, c->speed);
863 
864 	sndbuf_setfmt(c->bufhard, hwfmt);
865 
866 	chn_syncstate(c);
867 
868 	return (0);
869 }
870