sys/dev/sound/pcm/vchan.c

   1 /*-
   2  * Copyright (c) 2001 Cameron Grant <cg@freebsd.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/dev/sound/pcm/vchan.c,v 1.17.2.5 2007/02/04 06:17:14 ariff Exp $
  27  */
  28
  29 #include <dev/sound/pcm/sound.h>
  30 #include <dev/sound/pcm/vchan.h>
  31 #include "feeder_if.h"
  32
  33 SND_DECLARE_FILE("$DragonFly: src/sys/dev/sound/pcm/vchan.c,v 1.8 2008/01/06 16:55:51 swildner Exp $");
  34
  35 /*
  36  * Default speed
  37  */
  38 #define VCHAN_DEFAULT_SPEED     48000
  39
  40 extern int feeder_rate_ratemin;
  41 extern int feeder_rate_ratemax;
  42
  43 struct vchinfo {
  44         u_int32_t spd, fmt, blksz, bps, run;
  45         struct pcm_channel *channel, *parent;
  46         struct pcmchan_caps caps;
  47 };
  48
  49 static u_int32_t vchan_fmt[] = {
  50         AFMT_STEREO | AFMT_S16_LE,
  51         0
  52 };
  53
  54 /*
  55  * These values are: (1.022**v-1)*65536/(1.022**100-1)
  56  *
  57  * Inspired by inverting opensound (BSDL'd)'s mix_cvt.
  58  */
  59 static int log_mix_cvt[101] = {
  60 0, 184, 373, 565, 762, 964, 1170, 1380, 1595, 1814, 2039, 2268, 2503, 2742,
  61 2987, 3238, 3493, 3755, 4022, 4295, 4574, 4859, 5151, 5449, 5753, 6064, 6382,
  62 6707, 7039, 7379, 7726, 8080, 8442, 8813, 9191, 9578, 9973, 10377, 10790,
  63 11212, 11643, 12084, 12534, 12995, 13465, 13946, 14437, 14940, 15453, 15977,
  64 16513, 17061, 17621, 18193, 18778, 19376, 19987, 20611, 21249, 21901, 22567,
  65 23248, 23944, 24656, 25383, 26126, 26885, 27661, 28454, 29265, 30093, 30940,
  66 31805, 32689, 33593, 34517, 35461, 36425, 37411, 38419, 39449, 40501, 41577,
  67 42676, 43799, 44947, 46121, 47320, 48546, 49798, 51078, 52387, 53724, 55090,
  68 56487, 57914, 59373, 60864, 62387, 63944, 65536
  69 };
  70
  71 static int
  72 vchan_mix_s16(int16_t *to, int16_t *tmp, unsigned int count, int volume)
  73 {
  74         /*
  75          * to is the output buffer, tmp is the input buffer
  76          * count is the number of 16bit samples to mix
  77          * volume is in range 0-100, (left | (right << 8))
  78          */
  79         int i;
  80         int x;
  81         int scale[2];
  82         int doscale;
  83
  84         scale[0] = log_mix_cvt[volume & 0xff];
  85         scale[1] = log_mix_cvt[(volume >> 8) & 0xff];
  86         doscale = volume != (100 | (100 << 8));
  87
  88         for(i = 0; i < count; i++) {
  89                 x = to[i];
  90                 if (doscale)
  91                         x += ((int)tmp[i] * scale[i % 2]) >> 16;
  92                 else
  93                         x += tmp[i];
  94                 if (x < -32768) {
  95                         /* kprintf("%d + %d = %d (u)\n", to[i], tmp[i], x); */
  96                         x = -32768;
  97                 }
  98                 if (x > 32767) {
  99                         /* kprintf("%d + %d = %d (o)\n", to[i], tmp[i], x); */
 100                         x = 32767;
 101                 }
 102                 to[i] = x & 0x0000ffff;
 103         }
 104         return 0;
 105 }
 106
 107 static int
 108 feed_vchan_s16(struct pcm_feeder *f, struct pcm_channel *c, u_int8_t *b, u_int32_t count, void *source)
 109 {
 110         /* we're going to abuse things a bit */
 111         struct snd_dbuf *src = source;
 112         struct pcmchan_children *cce;
 113         struct pcm_channel *ch;
 114         uint32_t sz;
 115         int16_t *tmp, *dst;
 116         unsigned int cnt, rcnt = 0;
 117
 118         #if 0
 119         if (sndbuf_getsize(src) < count)
 120                 panic("feed_vchan_s16(%s): tmp buffer size %d < count %d, flags = 0x%x",
 121                     c->name, sndbuf_getsize(src), count, c->flags);
 122         #endif
 123         sz = sndbuf_getsize(src);
 124         if (sz < count)
 125                 count = sz;
 126         count &= ~1;
 127         if (count < 2)
 128                 return 0;
 129         bzero(b, count);
 130
 131         /*
 132          * we are going to use our source as a temporary buffer since it's
 133          * got no other purpose.  we obtain our data by traversing the channel
 134          * list of children and calling vchan_mix_* to mix count bytes from each
 135          * into our destination buffer, b
 136          */
 137         dst = (int16_t *)b;
 138         tmp = (int16_t *)sndbuf_getbuf(src);
 139         bzero(tmp, count);
 140         SLIST_FOREACH(cce, &c->children, link) {
 141                 ch = cce->channel;
 142                 CHN_LOCK(ch);
 143                 if (ch->flags & CHN_F_TRIGGERED) {
 144                         if (ch->flags & CHN_F_MAPPED)
 145                                 sndbuf_acquire(ch->bufsoft, NULL, sndbuf_getfree(ch->bufsoft));
 146                         cnt = FEEDER_FEED(ch->feeder, ch, (u_int8_t *)tmp, count, ch->bufsoft);
 147                         vchan_mix_s16(dst, tmp, cnt >> 1, ch->volume);
 148                         if (cnt > rcnt)
 149                                 rcnt = cnt;
 150                 }
 151                 CHN_UNLOCK(ch);
 152         }
 153
 154         return rcnt & ~1;
 155 }
 156
 157 static struct pcm_feederdesc feeder_vchan_s16_desc[] = {
 158         {FEEDER_MIXER, AFMT_S16_LE | AFMT_STEREO, AFMT_S16_LE | AFMT_STEREO, 0},
 159         {0},
 160 };
 161 static kobj_method_t feeder_vchan_s16_methods[] = {
 162         KOBJMETHOD(feeder_feed,         feed_vchan_s16),
 163         KOBJMETHOD_END
 164 };
 165 FEEDER_DECLARE(feeder_vchan_s16, 2, NULL);
 166
 167 /************************************************************/
 168
 169 static void *
 170 vchan_init(kobj_t obj, void *devinfo, struct snd_dbuf *b, struct pcm_channel *c, int dir)
 171 {
 172         struct vchinfo *ch;
 173         struct pcm_channel *parent = devinfo;
 174
 175         KASSERT(dir == PCMDIR_PLAY, ("vchan_init: bad direction"));
 176         ch = kmalloc(sizeof(*ch), M_DEVBUF, M_WAITOK | M_ZERO);
 177         ch->parent = parent;
 178         ch->channel = c;
 179         ch->fmt = AFMT_U8;
 180         ch->spd = DSP_DEFAULT_SPEED;
 181         ch->blksz = 2048;
 182
 183         c->flags |= CHN_F_VIRTUAL;
 184
 185         return ch;
 186 }
 187
 188 static int
 189 vchan_free(kobj_t obj, void *data)
 190 {
 191         kfree(data, M_DEVBUF);
 192         return 0;
 193 }
 194
 195 static int
 196 vchan_setformat(kobj_t obj, void *data, u_int32_t format)
 197 {
 198         struct vchinfo *ch = data;
 199         struct pcm_channel *parent = ch->parent;
 200         struct pcm_channel *channel = ch->channel;
 201
 202         ch->fmt = format;
 203         ch->bps = 1;
 204         ch->bps <<= (ch->fmt & AFMT_STEREO)? 1 : 0;
 205         if (ch->fmt & AFMT_16BIT)
 206                 ch->bps <<= 1;
 207         else if (ch->fmt & AFMT_24BIT)
 208                 ch->bps *= 3;
 209         else if (ch->fmt & AFMT_32BIT)
 210                 ch->bps <<= 2;
 211         CHN_UNLOCK(channel);
 212         chn_notify(parent, CHN_N_FORMAT);
 213         CHN_LOCK(channel);
 214         sndbuf_setfmt(channel->bufsoft, format);
 215         return 0;
 216 }
 217
 218 static int
 219 vchan_setspeed(kobj_t obj, void *data, u_int32_t speed)
 220 {
 221         struct vchinfo *ch = data;
 222         struct pcm_channel *parent = ch->parent;
 223         struct pcm_channel *channel = ch->channel;
 224
 225         ch->spd = speed;
 226         CHN_UNLOCK(channel);
 227         CHN_LOCK(parent);
 228         speed = sndbuf_getspd(parent->bufsoft);
 229         CHN_UNLOCK(parent);
 230         CHN_LOCK(channel);
 231         return speed;
 232 }
 233
 234 static int
 235 vchan_setblocksize(kobj_t obj, void *data, u_int32_t blocksize)
 236 {
 237         struct vchinfo *ch = data;
 238         struct pcm_channel *channel = ch->channel;
 239         struct pcm_channel *parent = ch->parent;
 240         /* struct pcm_channel *channel = ch->channel; */
 241         int prate, crate;
 242
 243         ch->blksz = blocksize;
 244         /* CHN_UNLOCK(channel); */
 245         sndbuf_setblksz(channel->bufhard, blocksize);
 246         chn_notify(parent, CHN_N_BLOCKSIZE);
 247         CHN_LOCK(parent);
 248         /* CHN_LOCK(channel); */
 249
 250         crate = ch->spd * ch->bps;
 251         prate = sndbuf_getspd(parent->bufsoft) * sndbuf_getbps(parent->bufsoft);
 252         blocksize = sndbuf_getblksz(parent->bufsoft);
 253         CHN_UNLOCK(parent);
 254         blocksize *= prate;
 255         blocksize /= crate;
 256
 257         return blocksize;
 258 }
 259
 260 static int
 261 vchan_trigger(kobj_t obj, void *data, int go)
 262 {
 263         struct vchinfo *ch = data;
 264         struct pcm_channel *parent = ch->parent;
 265         struct pcm_channel *channel = ch->channel;
 266
 267         if (go == PCMTRIG_EMLDMAWR || go == PCMTRIG_EMLDMARD)
 268                 return 0;
 269
 270         ch->run = (go == PCMTRIG_START)? 1 : 0;
 271         CHN_UNLOCK(channel);
 272         chn_notify(parent, CHN_N_TRIGGER);
 273         CHN_LOCK(channel);
 274
 275         return 0;
 276 }
 277
 278 static struct pcmchan_caps *
 279 vchan_getcaps(kobj_t obj, void *data)
 280 {
 281         struct vchinfo *ch = data;
 282
 283         ch->caps.minspeed = sndbuf_getspd(ch->parent->bufsoft);
 284         ch->caps.maxspeed = ch->caps.minspeed;
 285         ch->caps.fmtlist = vchan_fmt;
 286         ch->caps.caps = 0;
 287
 288         return &ch->caps;
 289 }
 290
 291 static kobj_method_t vchan_methods[] = {
 292         KOBJMETHOD(channel_init,                vchan_init),
 293         KOBJMETHOD(channel_free,                vchan_free),
 294         KOBJMETHOD(channel_setformat,           vchan_setformat),
 295         KOBJMETHOD(channel_setspeed,            vchan_setspeed),
 296         KOBJMETHOD(channel_setblocksize,        vchan_setblocksize),
 297         KOBJMETHOD(channel_trigger,             vchan_trigger),
 298         KOBJMETHOD(channel_getcaps,             vchan_getcaps),
 299         KOBJMETHOD_END
 300 };
 301 CHANNEL_DECLARE(vchan);
 302
 303 #if 0
 304 /*
 305  * On the fly vchan rate settings
 306  */
 307 #ifdef SND_DYNSYSCTL
 308 static int
 309 sysctl_hw_snd_vchanrate(SYSCTL_HANDLER_ARGS)
 310 {
 311         struct snddev_info *d;
 312         struct snddev_channel *sce;
 313         struct pcm_channel *c, *ch = NULL, *fake;
 314         struct pcmchan_caps *caps;
 315         int err = 0;
 316         int newspd = 0;
 317
 318         d = oidp->oid_arg1;
 319         if (!(d->flags & SD_F_AUTOVCHAN) || d->vchancount < 1)
 320                 return EINVAL;
 321         if (pcm_inprog(d, 1) != 1 && req->newptr != NULL) {
 322                 pcm_inprog(d, -1);
 323                 return EINPROGRESS;
 324         }
 325         SLIST_FOREACH(sce, &d->channels, link) {
 326                 c = sce->channel;
 327                 CHN_LOCK(c);
 328                 if (c->direction == PCMDIR_PLAY) {
 329                         if (c->flags & CHN_F_VIRTUAL) {
 330                                 /* Sanity check */
 331                                 if (ch != NULL && ch != c->parentchannel) {
 332                                         CHN_UNLOCK(c);
 333                                         pcm_inprog(d, -1);
 334                                         return EINVAL;
 335                                 }
 336                                 if (req->newptr != NULL &&
 337                                                 (c->flags & CHN_F_BUSY)) {
 338                                         CHN_UNLOCK(c);
 339                                         pcm_inprog(d, -1);
 340                                         return EBUSY;
 341                                 }
 342                         } else if (c->flags & CHN_F_HAS_VCHAN) {
 343                                 /* No way!! */
 344                                 if (ch != NULL) {
 345                                         CHN_UNLOCK(c);
 346                                         pcm_inprog(d, -1);
 347                                         return EINVAL;
 348                                 }
 349                                 ch = c;
 350                                 newspd = ch->speed;
 351                         }
 352                 }
 353                 CHN_UNLOCK(c);
 354         }
 355         if (ch == NULL) {
 356                 pcm_inprog(d, -1);
 357                 return EINVAL;
 358         }
 359         err = sysctl_handle_int(oidp, &newspd, sizeof(newspd), req);
 360         if (err == 0 && req->newptr != NULL) {
 361                 if (newspd < 1 || newspd < feeder_rate_ratemin ||
 362                                 newspd > feeder_rate_ratemax) {
 363                         pcm_inprog(d, -1);
 364                         return EINVAL;
 365                 }
 366                 CHN_LOCK(ch);
 367                 caps = chn_getcaps(ch);
 368                 if (caps == NULL || newspd < caps->minspeed ||
 369                                 newspd > caps->maxspeed) {
 370                         CHN_UNLOCK(ch);
 371                         pcm_inprog(d, -1);
 372                         return EINVAL;
 373                 }
 374                 if (newspd != ch->speed) {
 375                         err = chn_setspeed(ch, newspd);
 376                         /*
 377                          * Try to avoid FEEDER_RATE on parent channel if the
 378                          * requested value is not supported by the hardware.
 379                          */
 380                         if (!err && (ch->feederflags & (1 << FEEDER_RATE))) {
 381                                 newspd = sndbuf_getspd(ch->bufhard);
 382                                 err = chn_setspeed(ch, newspd);
 383                         }
 384                         CHN_UNLOCK(ch);
 385                         if (err == 0) {
 386                                 fake = pcm_getfakechan(d);
 387                                 if (fake != NULL) {
 388                                         CHN_LOCK(fake);
 389                                         fake->speed = newspd;
 390                                         CHN_UNLOCK(fake);
 391                                 }
 392                         }
 393                 } else
 394                         CHN_UNLOCK(ch);
 395         }
 396         pcm_inprog(d, -1);
 397         return err;
 398 }
 399 #endif
 400 #endif
 401
 402 /* virtual channel interface */
 403
 404 int
 405 vchan_create(struct pcm_channel *parent)
 406 {
 407         struct snddev_info *d = parent->parentsnddev;
 408         struct pcmchan_children *pce;
 409         struct pcm_channel *child, *fake;
 410         struct pcmchan_caps *parent_caps;
 411         int err, first, speed = 0;
 412
 413         if (!(parent->flags & CHN_F_BUSY))
 414                 return EBUSY;
 415
 416
 417         CHN_UNLOCK(parent);
 418
 419         pce = kmalloc(sizeof(*pce), M_DEVBUF, M_WAITOK | M_ZERO);
 420
 421         /* create a new playback channel */
 422         child = pcm_chn_create(d, parent, &vchan_class, PCMDIR_VIRTUAL, parent);
 423         if (!child) {
 424                 kfree(pce, M_DEVBUF);
 425                 CHN_LOCK(parent);
 426                 return ENODEV;
 427         }
 428         pce->channel = child;
 429
 430         /* add us to our grandparent's channel list */
 431         /*
 432          * XXX maybe we shouldn't always add the dev_t
 433          */
 434         err = pcm_chn_add(d, child);
 435         if (err) {
 436                 pcm_chn_destroy(child);
 437                 kfree(pce, M_DEVBUF);
 438                 CHN_LOCK(parent);
 439                 return err;
 440         }
 441
 442         CHN_LOCK(parent);
 443         /* add us to our parent channel's children */
 444         first = SLIST_EMPTY(&parent->children);
 445         SLIST_INSERT_HEAD(&parent->children, pce, link);
 446         parent->flags |= CHN_F_HAS_VCHAN;
 447
 448         if (first) {
 449                 parent_caps = chn_getcaps(parent);
 450                 if (parent_caps == NULL)
 451                         err = EINVAL;
 452
 453                 if (!err)
 454                         err = chn_reset(parent, AFMT_STEREO | AFMT_S16_LE);
 455
 456                 if (!err) {
 457                         fake = pcm_getfakechan(d);
 458                         if (fake != NULL) {
 459                                 /*
 460                                  * Avoid querying kernel hint, use saved value
 461                                  * from fake channel.
 462                                  */
 463                                 CHN_UNLOCK(parent);
 464                                 CHN_LOCK(fake);
 465                                 speed = fake->speed;
 466                                 CHN_UNLOCK(fake);
 467                                 CHN_LOCK(parent);
 468                         }
 469
 470                         /*
 471                          * This is very sad. Few soundcards advertised as being
 472                          * able to do (insanely) higher/lower speed, but in
 473                          * reality, they simply can't. At least, we give user chance
 474                          * to set sane value via kernel hints or sysctl.
 475                          */
 476                         if (speed < 1) {
 477                                 int r;
 478                                 CHN_UNLOCK(parent);
 479                                 r = resource_int_value(device_get_name(parent->dev),
 480                                                         device_get_unit(parent->dev),
 481                                                                 "vchanrate", &speed);
 482                                 CHN_LOCK(parent);
 483                                 if (r != 0) {
 484                                         /*
 485                                          * Workaround for sb16 running
 486                                          * poorly at 45k / 49k.
 487                                          */
 488                                         switch (parent_caps->maxspeed) {
 489                                         case 45000:
 490                                         case 49000:
 491                                                 speed = 44100;
 492                                                 break;
 493                                         default:
 494                                                 speed = VCHAN_DEFAULT_SPEED;
 495                                                 break;
 496                                         }
 497                                 }
 498                         }
 499
 500                         /*
 501                          * Limit speed based on driver caps.
 502                          * This is supposed to help fixed rate, non-VRA
 503                          * AC97 cards, but.. (see below)
 504                          */
 505                         if (speed < parent_caps->minspeed)
 506                                 speed = parent_caps->minspeed;
 507                         if (speed > parent_caps->maxspeed)
 508                                 speed = parent_caps->maxspeed;
 509
 510                         /*
 511                          * We still need to limit the speed between
 512                          * feeder_rate_ratemin <-> feeder_rate_ratemax. This is
 513                          * just an escape goat if all of the above failed
 514                          * miserably.
 515                          */
 516                         if (speed < feeder_rate_ratemin)
 517                                 speed = feeder_rate_ratemin;
 518                         if (speed > feeder_rate_ratemax)
 519                                 speed = feeder_rate_ratemax;
 520
 521                         err = chn_setspeed(parent, speed);
 522                         /*
 523                          * Try to avoid FEEDER_RATE on parent channel if the
 524                          * requested value is not supported by the hardware.
 525                          */
 526                         if (!err && (parent->feederflags & (1 << FEEDER_RATE))) {
 527                                 speed = sndbuf_getspd(parent->bufhard);
 528                                 err = chn_setspeed(parent, speed);
 529                         }
 530
 531                         if (!err && fake != NULL) {
 532                                 /*
 533                                  * Save new value to fake channel.
 534                                  */
 535                                 CHN_UNLOCK(parent);
 536                                 CHN_LOCK(fake);
 537                                 fake->speed = speed;
 538                                 CHN_UNLOCK(fake);
 539                                 CHN_LOCK(parent);
 540                         }
 541                 }
 542
 543                 if (err) {
 544                         SLIST_REMOVE(&parent->children, pce, pcmchan_children, link);
 545                         parent->flags &= ~CHN_F_HAS_VCHAN;
 546                         CHN_UNLOCK(parent);
 547                         kfree(pce, M_DEVBUF);
 548                         if (pcm_chn_remove(d, child) == 0)
 549                                 pcm_chn_destroy(child);
 550                         CHN_LOCK(parent);
 551                         return err;
 552                 }
 553         }
 554
 555         return 0;
 556 }
 557
 558 int
 559 vchan_destroy(struct pcm_channel *c)
 560 {
 561         struct pcm_channel *parent = c->parentchannel;
 562         struct snddev_info *d = parent->parentsnddev;
 563         struct pcmchan_children *pce;
 564         struct snddev_channel *sce;
 565         uint32_t spd;
 566         int err;
 567
 568         CHN_LOCK(parent);
 569         if (!(parent->flags & CHN_F_BUSY)) {
 570                 CHN_UNLOCK(parent);
 571                 return EBUSY;
 572         }
 573         if (SLIST_EMPTY(&parent->children)) {
 574                 CHN_UNLOCK(parent);
 575                 return EINVAL;
 576         }
 577
 578         /* remove us from our parent's children list */
 579         SLIST_FOREACH(pce, &parent->children, link) {
 580                 if (pce->channel == c)
 581                         goto gotch;
 582         }
 583         CHN_UNLOCK(parent);
 584         return EINVAL;
 585 gotch:
 586         SLIST_FOREACH(sce, &d->channels, link) {
 587                 if (sce->channel == c) {
 588                         if (sce->dsp_dev) {
 589                                 destroy_dev(sce->dsp_dev);
 590                                 sce->dsp_dev = NULL;
 591                         }
 592                         d->devcount--;
 593                         break;
 594                 }
 595         }
 596         SLIST_REMOVE(&parent->children, pce, pcmchan_children, link);
 597         kfree(pce, M_DEVBUF);
 598
 599         if (SLIST_EMPTY(&parent->children)) {
 600                 parent->flags &= ~(CHN_F_BUSY | CHN_F_HAS_VCHAN);
 601                 spd = parent->speed;
 602                 if (chn_reset(parent, parent->format) == 0)
 603                         chn_setspeed(parent, spd);
 604         }
 605
 606         /* remove us from our grandparent's channel list */
 607         err = pcm_chn_remove(d, c);
 608
 609         CHN_UNLOCK(parent);
 610         /* destroy ourselves */
 611         if (!err)
 612                 err = pcm_chn_destroy(c);
 613
 614         return err;
 615 }
 616
 617 int
 618 vchan_initsys(device_t dev)
 619 {
 620 #ifdef SND_DYNSYSCTL
 621         struct snddev_info *d;
 622
 623         d = device_get_softc(dev);
 624         SYSCTL_ADD_PROC(snd_sysctl_tree(dev), SYSCTL_CHILDREN(snd_sysctl_tree_top(dev)),
 625             OID_AUTO, "vchans", CTLTYPE_INT | CTLFLAG_RW, d, sizeof(d),
 626             sysctl_hw_snd_vchans, "I", "");
 627 #if 0
 628         SYSCTL_ADD_PROC(snd_sysctl_tree(dev), SYSCTL_CHILDREN(snd_sysctl_tree_top(dev)),
 629             OID_AUTO, "vchanrate", CTLTYPE_INT | CTLFLAG_RW, d, sizeof(d),
 630             sysctl_hw_snd_vchanrate, "I", "");
 631 #endif
 632 #endif
 633
 634         return 0;
 635 }