audio/ossaudio.c

   1 /*
   2  * QEMU OSS audio driver
   3  *
   4  * Copyright (c) 2003-2005 Vassili Karpov (malc)
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include <sys/mman.h>
  25 #include <sys/types.h>
  26 #include <sys/ioctl.h>
  27 #include <sys/soundcard.h>
  28 #include "vl.h"
  29
  30 #define AUDIO_CAP "oss"
  31 #include "audio_int.h"
  32
  33 typedef struct OSSVoiceOut {
  34     HWVoiceOut hw;
  35     void *pcm_buf;
  36     int fd;
  37     int nfrags;
  38     int fragsize;
  39     int mmapped;
  40     int old_optr;
  41 } OSSVoiceOut;
  42
  43 typedef struct OSSVoiceIn {
  44     HWVoiceIn hw;
  45     void *pcm_buf;
  46     int fd;
  47     int nfrags;
  48     int fragsize;
  49     int old_optr;
  50 } OSSVoiceIn;
  51
  52 static struct {
  53     int try_mmap;
  54     int nfrags;
  55     int fragsize;
  56     const char *devpath_out;
  57     const char *devpath_in;
  58 } conf = {
  59     .try_mmap = 0,
  60     .nfrags = 4,
  61     .fragsize = 4096,
  62     .devpath_out = "/dev/dsp",
  63     .devpath_in = "/dev/dsp"
  64 };
  65
  66 struct oss_params {
  67     int freq;
  68     audfmt_e fmt;
  69     int nchannels;
  70     int nfrags;
  71     int fragsize;
  72 };
  73
  74 static void GCC_FMT_ATTR (2, 3) oss_logerr (int err, const char *fmt, ...)
  75 {
  76     va_list ap;
  77
  78     AUD_vlog (AUDIO_CAP, fmt, ap);
  79
  80     va_start (ap, fmt);
  81     AUD_log (AUDIO_CAP, "Reason: %s\n", strerror (err));
  82     va_end (ap);
  83 }
  84
  85 static void GCC_FMT_ATTR (3, 4) oss_logerr2 (
  86     int err,
  87     const char *typ,
  88     const char *fmt,
  89     ...
  90     )
  91 {
  92     va_list ap;
  93
  94     AUD_log (AUDIO_CAP, "Can not initialize %s\n", typ);
  95
  96     va_start (ap, fmt);
  97     AUD_vlog (AUDIO_CAP, fmt, ap);
  98     va_end (ap);
  99
 100     AUD_log (AUDIO_CAP, "Reason: %s\n", strerror (err));
 101 }
 102
 103 static void oss_anal_close (int *fdp)
 104 {
 105     int err = close (*fdp);
 106     if (err) {
 107         oss_logerr (errno, "Failed to close file(fd=%d)\n", *fdp);
 108     }
 109     *fdp = -1;
 110 }
 111
 112 static int oss_write (SWVoiceOut *sw, void *buf, int len)
 113 {
 114     return audio_pcm_sw_write (sw, buf, len);
 115 }
 116
 117 static int aud_to_ossfmt (audfmt_e fmt)
 118 {
 119     switch (fmt) {
 120     case AUD_FMT_S8:
 121         return AFMT_S8;
 122
 123     case AUD_FMT_U8:
 124         return AFMT_U8;
 125
 126     case AUD_FMT_S16:
 127         return AFMT_S16_LE;
 128
 129     case AUD_FMT_U16:
 130         return AFMT_U16_LE;
 131
 132     default:
 133         dolog ("Internal logic error: Bad audio format %d\n", fmt);
 134 #ifdef DEBUG_AUDIO
 135         abort ();
 136 #endif
 137         return AFMT_U8;
 138     }
 139 }
 140
 141 static int oss_to_audfmt (int ossfmt, audfmt_e *fmt, int *endianness)
 142 {
 143     switch (ossfmt) {
 144     case AFMT_S8:
 145         *endianness =0;
 146         *fmt = AUD_FMT_S8;
 147         break;
 148
 149     case AFMT_U8:
 150         *endianness = 0;
 151         *fmt = AUD_FMT_U8;
 152         break;
 153
 154     case AFMT_S16_LE:
 155         *endianness = 0;
 156         *fmt = AUD_FMT_S16;
 157         break;
 158
 159     case AFMT_U16_LE:
 160         *endianness = 0;
 161         *fmt = AUD_FMT_U16;
 162         break;
 163
 164     case AFMT_S16_BE:
 165         *endianness = 1;
 166         *fmt = AUD_FMT_S16;
 167         break;
 168
 169     case AFMT_U16_BE:
 170         *endianness = 1;
 171         *fmt = AUD_FMT_U16;
 172         break;
 173
 174     default:
 175         dolog ("Unrecognized audio format %d\n", ossfmt);
 176         return -1;
 177     }
 178
 179     return 0;
 180 }
 181
 182 #ifdef DEBUG_MISMATCHES
 183 static void oss_dump_info (struct oss_params *req, struct oss_params *obt)
 184 {
 185     dolog ("parameter | requested value | obtained value\n");
 186     dolog ("format    |      %10d |     %10d\n", req->fmt, obt->fmt);
 187     dolog ("channels  |      %10d |     %10d\n",
 188            req->nchannels, obt->nchannels);
 189     dolog ("frequency |      %10d |     %10d\n", req->freq, obt->freq);
 190     dolog ("nfrags    |      %10d |     %10d\n", req->nfrags, obt->nfrags);
 191     dolog ("fragsize  |      %10d |     %10d\n",
 192            req->fragsize, obt->fragsize);
 193 }
 194 #endif
 195
 196 static int oss_open (int in, struct oss_params *req,
 197                      struct oss_params *obt, int *pfd)
 198 {
 199     int fd;
 200     int mmmmssss;
 201     audio_buf_info abinfo;
 202     int fmt, freq, nchannels;
 203     const char *dspname = in ? conf.devpath_in : conf.devpath_out;
 204     const char *typ = in ? "ADC" : "DAC";
 205
 206     fd = open (dspname, (in ? O_RDONLY : O_WRONLY) | O_NONBLOCK);
 207     if (-1 == fd) {
 208         oss_logerr2 (errno, typ, "Failed to open `%s'\n", dspname);
 209         return -1;
 210     }
 211
 212     freq = req->freq;
 213     nchannels = req->nchannels;
 214     fmt = req->fmt;
 215
 216     if (ioctl (fd, SNDCTL_DSP_SAMPLESIZE, &fmt)) {
 217         oss_logerr2 (errno, typ, "Failed to set sample size %d\n", req->fmt);
 218         goto err;
 219     }
 220
 221     if (ioctl (fd, SNDCTL_DSP_CHANNELS, &nchannels)) {
 222         oss_logerr2 (errno, typ, "Failed to set number of channels %d\n",
 223                      req->nchannels);
 224         goto err;
 225     }
 226
 227     if (ioctl (fd, SNDCTL_DSP_SPEED, &freq)) {
 228         oss_logerr2 (errno, typ, "Failed to set frequency %d\n", req->freq);
 229         goto err;
 230     }
 231
 232     if (ioctl (fd, SNDCTL_DSP_NONBLOCK)) {
 233         oss_logerr2 (errno, typ, "Failed to set non-blocking mode\n");
 234         goto err;
 235     }
 236
 237     mmmmssss = (req->nfrags << 16) | lsbindex (req->fragsize);
 238     if (ioctl (fd, SNDCTL_DSP_SETFRAGMENT, &mmmmssss)) {
 239         oss_logerr2 (errno, typ, "Failed to set buffer length (%d, %d)\n",
 240                      req->nfrags, req->fragsize);
 241         goto err;
 242     }
 243
 244     if (ioctl (fd, in ? SNDCTL_DSP_GETISPACE : SNDCTL_DSP_GETOSPACE, &abinfo)) {
 245         oss_logerr2 (errno, typ, "Failed to get buffer length\n");
 246         goto err;
 247     }
 248
 249     obt->fmt = fmt;
 250     obt->nchannels = nchannels;
 251     obt->freq = freq;
 252     obt->nfrags = abinfo.fragstotal;
 253     obt->fragsize = abinfo.fragsize;
 254     *pfd = fd;
 255
 256     if ((req->fmt != obt->fmt) ||
 257         (req->nchannels != obt->nchannels) ||
 258         (req->freq != obt->freq) ||
 259         (req->fragsize != obt->fragsize) ||
 260         (req->nfrags != obt->nfrags)) {
 261 #ifdef DEBUG_MISMATCHES
 262         dolog ("Audio parameters mismatch\n");
 263         oss_dump_info (req, obt);
 264 #endif
 265     }
 266
 267 #ifdef DEBUG
 268     oss_dump_info (req, obt);
 269 #endif
 270     return 0;
 271
 272  err:
 273     oss_anal_close (&fd);
 274     return -1;
 275 }
 276
 277 static int oss_run_out (HWVoiceOut *hw)
 278 {
 279     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
 280     int err, rpos, live, decr;
 281     int samples;
 282     uint8_t *dst;
 283     st_sample_t *src;
 284     struct audio_buf_info abinfo;
 285     struct count_info cntinfo;
 286
 287     live = audio_pcm_hw_get_live_out (hw);
 288     if (!live) {
 289         return 0;
 290     }
 291
 292     if (oss->mmapped) {
 293         int bytes;
 294
 295         err = ioctl (oss->fd, SNDCTL_DSP_GETOPTR, &cntinfo);
 296         if (err < 0) {
 297             oss_logerr (errno, "SNDCTL_DSP_GETOPTR failed\n");
 298             return 0;
 299         }
 300
 301         if (cntinfo.ptr == oss->old_optr) {
 302             if (abs (hw->samples - live) < 64) {
 303                 dolog ("warning: overrun\n");
 304             }
 305             return 0;
 306         }
 307
 308         if (cntinfo.ptr > oss->old_optr) {
 309             bytes = cntinfo.ptr - oss->old_optr;
 310         }
 311         else {
 312             bytes = hw->bufsize + cntinfo.ptr - oss->old_optr;
 313         }
 314
 315         decr = audio_MIN (bytes >> hw->info.shift, live);
 316     }
 317     else {
 318         err = ioctl (oss->fd, SNDCTL_DSP_GETOSPACE, &abinfo);
 319         if (err < 0) {
 320             oss_logerr (errno, "SNDCTL_DSP_GETOPTR failed\n");
 321             return 0;
 322         }
 323
 324         if (abinfo.bytes < 0 || abinfo.bytes > hw->bufsize) {
 325             ldebug ("warning: invalid available size, size=%d bufsize=%d\n",
 326                     abinfo.bytes, hw->bufsize);
 327             return 0;
 328         }
 329
 330         decr = audio_MIN (abinfo.bytes >> hw->info.shift, live);
 331         if (!decr) {
 332             return 0;
 333         }
 334     }
 335
 336     samples = decr;
 337     rpos = hw->rpos;
 338     while (samples) {
 339         int left_till_end_samples = hw->samples - rpos;
 340         int convert_samples = audio_MIN (samples, left_till_end_samples);
 341
 342         src = hw->mix_buf + rpos;
 343         dst = advance (oss->pcm_buf, rpos << hw->info.shift);
 344
 345         hw->clip (dst, src, convert_samples);
 346         if (!oss->mmapped) {
 347             int written;
 348
 349             written = write (oss->fd, dst, convert_samples << hw->info.shift);
 350             /* XXX: follow errno recommendations ? */
 351             if (written == -1) {
 352                 oss_logerr (
 353                     errno,
 354                     "Failed to write %d bytes of audio data from %p\n",
 355                     convert_samples << hw->info.shift,
 356                     dst
 357                     );
 358                 continue;
 359             }
 360
 361             if (written != convert_samples << hw->info.shift) {
 362                 int wsamples = written >> hw->info.shift;
 363                 int wbytes = wsamples << hw->info.shift;
 364                 if (wbytes != written) {
 365                     dolog ("warning: misaligned write %d (requested %d), "
 366                            "alignment %d\n",
 367                            wbytes, written, hw->info.align + 1);
 368                 }
 369                 mixeng_clear (src, wsamples);
 370                 decr -= wsamples;
 371                 rpos = (rpos + wsamples) % hw->samples;
 372                 break;
 373             }
 374         }
 375
 376         mixeng_clear (src, convert_samples);
 377
 378         rpos = (rpos + convert_samples) % hw->samples;
 379         samples -= convert_samples;
 380     }
 381     if (oss->mmapped) {
 382         oss->old_optr = cntinfo.ptr;
 383     }
 384
 385     hw->rpos = rpos;
 386     return decr;
 387 }
 388
 389 static void oss_fini_out (HWVoiceOut *hw)
 390 {
 391     int err;
 392     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
 393
 394     ldebug ("oss_fini\n");
 395     oss_anal_close (&oss->fd);
 396
 397     if (oss->pcm_buf) {
 398         if (oss->mmapped) {
 399             err = munmap (oss->pcm_buf, hw->bufsize);
 400             if (err) {
 401                 oss_logerr (errno, "Failed to unmap buffer %p, size %d\n",
 402                             oss->pcm_buf, hw->bufsize);
 403             }
 404         }
 405         else {
 406             qemu_free (oss->pcm_buf);
 407         }
 408         oss->pcm_buf = NULL;
 409     }
 410 }
 411
 412 static int oss_init_out (HWVoiceOut *hw, int freq, int nchannels, audfmt_e fmt)
 413 {
 414     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
 415     struct oss_params req, obt;
 416     int endianness;
 417     int err;
 418     int fd;
 419     audfmt_e effective_fmt;
 420
 421     req.fmt = aud_to_ossfmt (fmt);
 422     req.freq = freq;
 423     req.nchannels = nchannels;
 424     req.fragsize = conf.fragsize;
 425     req.nfrags = conf.nfrags;
 426
 427     if (oss_open (0, &req, &obt, &fd)) {
 428         return -1;
 429     }
 430
 431     err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
 432     if (err) {
 433         oss_anal_close (&fd);
 434         return -1;
 435     }
 436
 437     audio_pcm_init_info (
 438         &hw->info,
 439         obt.freq,
 440         obt.nchannels,
 441         effective_fmt,
 442         audio_need_to_swap_endian (endianness)
 443         );
 444     oss->nfrags = obt.nfrags;
 445     oss->fragsize = obt.fragsize;
 446     hw->bufsize = obt.nfrags * obt.fragsize;
 447
 448     oss->mmapped = 0;
 449     if (conf.try_mmap) {
 450         oss->pcm_buf = mmap (0, hw->bufsize, PROT_READ | PROT_WRITE,
 451                              MAP_SHARED, fd, 0);
 452         if (oss->pcm_buf == MAP_FAILED) {
 453             oss_logerr (errno, "Failed to map %d bytes of DAC\n",
 454                         hw->bufsize);
 455         } else {
 456             int err;
 457             int trig = 0;
 458             if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
 459                 oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
 460             }
 461             else {
 462                 trig = PCM_ENABLE_OUTPUT;
 463                 if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
 464                     oss_logerr (
 465                         errno,
 466                         "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
 467                         );
 468                 }
 469                 else {
 470                     oss->mmapped = 1;
 471                 }
 472             }
 473
 474             if (!oss->mmapped) {
 475                 err = munmap (oss->pcm_buf, hw->bufsize);
 476                 if (err) {
 477                     oss_logerr (errno, "Failed to unmap buffer %p size %d\n",
 478                                 oss->pcm_buf, hw->bufsize);
 479                 }
 480             }
 481         }
 482     }
 483
 484     if (!oss->mmapped) {
 485         oss->pcm_buf = qemu_mallocz (hw->bufsize);
 486         if (!oss->pcm_buf) {
 487             oss_anal_close (&fd);
 488             return -1;
 489         }
 490     }
 491
 492     oss->fd = fd;
 493     return 0;
 494 }
 495
 496 static int oss_ctl_out (HWVoiceOut *hw, int cmd, ...)
 497 {
 498     int trig;
 499     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
 500
 501     if (!oss->mmapped) {
 502         return 0;
 503     }
 504
 505     switch (cmd) {
 506     case VOICE_ENABLE:
 507         ldebug ("enabling voice\n");
 508         audio_pcm_info_clear_buf (&hw->info, oss->pcm_buf, hw->samples);
 509         trig = PCM_ENABLE_OUTPUT;
 510         if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
 511             oss_logerr (
 512                 errno,
 513                 "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
 514                 );
 515             return -1;
 516         }
 517         break;
 518
 519     case VOICE_DISABLE:
 520         ldebug ("disabling voice\n");
 521         trig = 0;
 522         if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
 523             oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
 524             return -1;
 525         }
 526         break;
 527     }
 528     return 0;
 529 }
 530
 531 static int oss_init_in (HWVoiceIn *hw,
 532                         int freq, int nchannels, audfmt_e fmt)
 533 {
 534     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
 535     struct oss_params req, obt;
 536     int endianness;
 537     int err;
 538     int fd;
 539     audfmt_e effective_fmt;
 540
 541     req.fmt = aud_to_ossfmt (fmt);
 542     req.freq = freq;
 543     req.nchannels = nchannels;
 544     req.fragsize = conf.fragsize;
 545     req.nfrags = conf.nfrags;
 546     if (oss_open (1, &req, &obt, &fd)) {
 547         return -1;
 548     }
 549
 550     err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
 551     if (err) {
 552         oss_anal_close (&fd);
 553         return -1;
 554     }
 555
 556     audio_pcm_init_info (
 557         &hw->info,
 558         obt.freq,
 559         obt.nchannels,
 560         effective_fmt,
 561         audio_need_to_swap_endian (endianness)
 562         );
 563     oss->nfrags = obt.nfrags;
 564     oss->fragsize = obt.fragsize;
 565     hw->bufsize = obt.nfrags * obt.fragsize;
 566     oss->pcm_buf = qemu_mallocz (hw->bufsize);
 567     if (!oss->pcm_buf) {
 568         oss_anal_close (&fd);
 569         return -1;
 570     }
 571
 572     oss->fd = fd;
 573     return 0;
 574 }
 575
 576 static void oss_fini_in (HWVoiceIn *hw)
 577 {
 578     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
 579
 580     oss_anal_close (&oss->fd);
 581
 582     if (oss->pcm_buf) {
 583         qemu_free (oss->pcm_buf);
 584         oss->pcm_buf = NULL;
 585     }
 586 }
 587
 588 static int oss_run_in (HWVoiceIn *hw)
 589 {
 590     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
 591     int hwshift = hw->info.shift;
 592     int i;
 593     int live = audio_pcm_hw_get_live_in (hw);
 594     int dead = hw->samples - live;
 595     size_t read_samples = 0;
 596     struct {
 597         int add;
 598         int len;
 599     } bufs[2] = {
 600         { hw->wpos, 0 },
 601         { 0, 0 }
 602     };
 603
 604     if (!dead) {
 605         return 0;
 606     }
 607
 608     if (hw->wpos + dead > hw->samples) {
 609         bufs[0].len = (hw->samples - hw->wpos) << hwshift;
 610         bufs[1].len = (dead - (hw->samples - hw->wpos)) << hwshift;
 611     }
 612     else {
 613         bufs[0].len = dead << hwshift;
 614     }
 615
 616
 617     for (i = 0; i < 2; ++i) {
 618         ssize_t nread;
 619
 620         if (bufs[i].len) {
 621             void *p = advance (oss->pcm_buf, bufs[i].add << hwshift);
 622             nread = read (oss->fd, p, bufs[i].len);
 623
 624             if (nread > 0) {
 625                 if (nread & hw->info.align) {
 626                     dolog ("warning: misaligned read %d (requested %d), "
 627                            "alignment %d\n", nread, bufs[i].add << hwshift,
 628                            hw->info.align + 1);
 629                 }
 630                 read_samples += nread >> hwshift;
 631                 hw->conv (hw->conv_buf + bufs[i].add, p, nread >> hwshift,
 632                           &nominal_volume);
 633             }
 634
 635             if (bufs[i].len - nread) {
 636                 if (nread == -1) {
 637                     switch (errno) {
 638                     case EINTR:
 639                     case EAGAIN:
 640                         break;
 641                     default:
 642                         oss_logerr (
 643                             errno,
 644                             "Failed to read %d bytes of audio (to %p)\n",
 645                             bufs[i].len, p
 646                             );
 647                         break;
 648                     }
 649                 }
 650                 break;
 651             }
 652         }
 653     }
 654
 655     hw->wpos = (hw->wpos + read_samples) % hw->samples;
 656     return read_samples;
 657 }
 658
 659 static int oss_read (SWVoiceIn *sw, void *buf, int size)
 660 {
 661     return audio_pcm_sw_read (sw, buf, size);
 662 }
 663
 664 static int oss_ctl_in (HWVoiceIn *hw, int cmd, ...)
 665 {
 666     (void) hw;
 667     (void) cmd;
 668     return 0;
 669 }
 670
 671 static void *oss_audio_init (void)
 672 {
 673     return &conf;
 674 }
 675
 676 static void oss_audio_fini (void *opaque)
 677 {
 678     (void) opaque;
 679 }
 680
 681 static struct audio_option oss_options[] = {
 682     {"FRAGSIZE", AUD_OPT_INT, &conf.fragsize,
 683      "Fragment size in bytes", NULL, 0},
 684     {"NFRAGS", AUD_OPT_INT, &conf.nfrags,
 685      "Number of fragments", NULL, 0},
 686     {"MMAP", AUD_OPT_BOOL, &conf.try_mmap,
 687      "Try using memory mapped access", NULL, 0},
 688     {"DAC_DEV", AUD_OPT_STR, &conf.devpath_out,
 689      "Path to DAC device", NULL, 0},
 690     {"ADC_DEV", AUD_OPT_STR, &conf.devpath_in,
 691      "Path to ADC device", NULL, 0},
 692     {NULL, 0, NULL, NULL, NULL, 0}
 693 };
 694
 695 static struct audio_pcm_ops oss_pcm_ops = {
 696     oss_init_out,
 697     oss_fini_out,
 698     oss_run_out,
 699     oss_write,
 700     oss_ctl_out,
 701
 702     oss_init_in,
 703     oss_fini_in,
 704     oss_run_in,
 705     oss_read,
 706     oss_ctl_in
 707 };
 708
 709 struct audio_driver oss_audio_driver = {
 710     INIT_FIELD (name           = ) "oss",
 711     INIT_FIELD (descr          = ) "OSS http://www.opensound.com",
 712     INIT_FIELD (options        = ) oss_options,
 713     INIT_FIELD (init           = ) oss_audio_init,
 714     INIT_FIELD (fini           = ) oss_audio_fini,
 715     INIT_FIELD (pcm_ops        = ) &oss_pcm_ops,
 716     INIT_FIELD (can_be_default = ) 1,
 717     INIT_FIELD (max_voices_out = ) INT_MAX,
 718     INIT_FIELD (max_voices_in  = ) INT_MAX,
 719     INIT_FIELD (voice_size_out = ) sizeof (OSSVoiceOut),
 720     INIT_FIELD (voice_size_in  = ) sizeof (OSSVoiceIn)
 721 };