audio/audio.c

   1 /*
   2  * QEMU Audio subsystem
   3  *
   4  * Copyright (c) 2003-2004 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 <assert.h>
  25 #include "vl.h"
  26
  27 #define USE_SDL_AUDIO
  28 #define USE_WAV_AUDIO
  29
  30 #include "audio/audio_int.h"
  31
  32 #define dolog(...) AUD_log ("audio", __VA_ARGS__)
  33 #ifdef DEBUG
  34 #define ldebug(...) dolog (__VA_ARGS__)
  35 #else
  36 #define ldebug(...)
  37 #endif
  38
  39 #define QC_AUDIO_DRV    "QEMU_AUDIO_DRV"
  40 #define QC_VOICES       "QEMU_VOICES"
  41 #define QC_FIXED_FORMAT "QEMU_FIXED_FORMAT"
  42 #define QC_FIXED_FREQ   "QEMU_FIXED_FREQ"
  43
  44 static HWVoice *hw_voices;
  45
  46 AudioState audio_state = {
  47     1,                          /* use fixed settings */
  48     44100,                      /* fixed frequency */
  49     2,                          /* fixed channels */
  50     AUD_FMT_S16,                /* fixed format */
  51     1,                          /* number of hw voices */
  52     -1                          /* voice size */
  53 };
  54
  55 /* http://www.df.lth.se/~john_e/gems/gem002d.html */
  56 /* http://www.multi-platforms.com/Tips/PopCount.htm */
  57 uint32_t popcount (uint32_t u)
  58 {
  59     u = ((u&0x55555555) + ((u>>1)&0x55555555));
  60     u = ((u&0x33333333) + ((u>>2)&0x33333333));
  61     u = ((u&0x0f0f0f0f) + ((u>>4)&0x0f0f0f0f));
  62     u = ((u&0x00ff00ff) + ((u>>8)&0x00ff00ff));
  63     u = ( u&0x0000ffff) + (u>>16);
  64     return u;
  65 }
  66
  67 inline uint32_t lsbindex (uint32_t u)
  68 {
  69     return popcount ((u&-u)-1);
  70 }
  71
  72 int audio_get_conf_int (const char *key, int defval)
  73 {
  74     int val = defval;
  75     char *strval;
  76
  77     strval = getenv (key);
  78     if (strval) {
  79         val = atoi (strval);
  80     }
  81
  82     return val;
  83 }
  84
  85 const char *audio_get_conf_str (const char *key, const char *defval)
  86 {
  87     const char *val = getenv (key);
  88     if (!val)
  89         return defval;
  90     else
  91         return val;
  92 }
  93
  94 void AUD_log (const char *cap, const char *fmt, ...)
  95 {
  96     va_list ap;
  97     fprintf (stderr, "%s: ", cap);
  98     va_start (ap, fmt);
  99     vfprintf (stderr, fmt, ap);
 100     va_end (ap);
 101 }
 102
 103 /*
 104  * Soft Voice
 105  */
 106 void pcm_sw_free_resources (SWVoice *sw)
 107 {
 108     if (sw->buf) qemu_free (sw->buf);
 109     if (sw->rate) st_rate_stop (sw->rate);
 110     sw->buf = NULL;
 111     sw->rate = NULL;
 112 }
 113
 114 int pcm_sw_alloc_resources (SWVoice *sw)
 115 {
 116     sw->buf = qemu_mallocz (sw->hw->samples * sizeof (st_sample_t));
 117     if (!sw->buf)
 118         return -1;
 119
 120     sw->rate = st_rate_start (sw->freq, sw->hw->freq);
 121     if (!sw->rate) {
 122         qemu_free (sw->buf);
 123         sw->buf = NULL;
 124         return -1;
 125     }
 126     return 0;
 127 }
 128
 129 void pcm_sw_fini (SWVoice *sw)
 130 {
 131     pcm_sw_free_resources (sw);
 132 }
 133
 134 int pcm_sw_init (SWVoice *sw, HWVoice *hw, int freq,
 135                  int nchannels, audfmt_e fmt)
 136 {
 137     int bits = 8, sign = 0;
 138
 139     switch (fmt) {
 140     case AUD_FMT_S8:
 141         sign = 1;
 142     case AUD_FMT_U8:
 143         break;
 144
 145     case AUD_FMT_S16:
 146         sign = 1;
 147     case AUD_FMT_U16:
 148         bits = 16;
 149         break;
 150     }
 151
 152     sw->hw = hw;
 153     sw->freq = freq;
 154     sw->fmt = fmt;
 155     sw->nchannels = nchannels;
 156     sw->shift = (nchannels == 2) + (bits == 16);
 157     sw->align = (1 << sw->shift) - 1;
 158     sw->left = 0;
 159     sw->pos = 0;
 160     sw->wpos = 0;
 161     sw->live = 0;
 162     sw->ratio = (sw->hw->freq * ((int64_t) INT_MAX)) / sw->freq;
 163     sw->bytes_per_second = sw->freq << sw->shift;
 164     sw->conv = mixeng_conv[nchannels == 2][sign][bits == 16];
 165
 166     pcm_sw_free_resources (sw);
 167     return pcm_sw_alloc_resources (sw);
 168 }
 169
 170 /* Hard voice */
 171 void pcm_hw_free_resources (HWVoice *hw)
 172 {
 173     if (hw->mix_buf)
 174         qemu_free (hw->mix_buf);
 175     hw->mix_buf = NULL;
 176 }
 177
 178 int pcm_hw_alloc_resources (HWVoice *hw)
 179 {
 180     hw->mix_buf = qemu_mallocz (hw->samples * sizeof (st_sample_t));
 181     if (!hw->mix_buf)
 182         return -1;
 183     return 0;
 184 }
 185
 186
 187 void pcm_hw_fini (HWVoice *hw)
 188 {
 189     if (hw->active) {
 190         ldebug ("pcm_hw_fini: %d %d %d\n", hw->freq, hw->nchannels, hw->fmt);
 191         pcm_hw_free_resources (hw);
 192         hw->pcm_ops->fini (hw);
 193         memset (hw, 0, audio_state.drv->voice_size);
 194     }
 195 }
 196
 197 void pcm_hw_gc (HWVoice *hw)
 198 {
 199     if (hw->nb_voices)
 200         return;
 201
 202     pcm_hw_fini (hw);
 203 }
 204
 205 int pcm_hw_get_live (HWVoice *hw)
 206 {
 207     int i, alive = 0, live = hw->samples;
 208
 209     for (i = 0; i < hw->nb_voices; i++) {
 210         if (hw->pvoice[i]->live) {
 211             live = audio_MIN (hw->pvoice[i]->live, live);
 212             alive += 1;
 213         }
 214     }
 215
 216     if (alive)
 217         return live;
 218     else
 219         return -1;
 220 }
 221
 222 int pcm_hw_get_live2 (HWVoice *hw, int *nb_active)
 223 {
 224     int i, alive = 0, live = hw->samples;
 225
 226     *nb_active = 0;
 227     for (i = 0; i < hw->nb_voices; i++) {
 228         if (hw->pvoice[i]->live) {
 229             if (hw->pvoice[i]->live < live) {
 230                 *nb_active = hw->pvoice[i]->active != 0;
 231                 live = hw->pvoice[i]->live;
 232             }
 233             alive += 1;
 234         }
 235     }
 236
 237     if (alive)
 238         return live;
 239     else
 240         return -1;
 241 }
 242
 243 void pcm_hw_dec_live (HWVoice *hw, int decr)
 244 {
 245     int i;
 246
 247     for (i = 0; i < hw->nb_voices; i++) {
 248         if (hw->pvoice[i]->live) {
 249             hw->pvoice[i]->live -= decr;
 250         }
 251     }
 252 }
 253
 254 void pcm_hw_clear (HWVoice *hw, void *buf, int len)
 255 {
 256     if (!len)
 257         return;
 258
 259     switch (hw->fmt) {
 260     case AUD_FMT_S16:
 261     case AUD_FMT_S8:
 262         memset (buf, len << hw->shift, 0x00);
 263         break;
 264
 265     case AUD_FMT_U8:
 266         memset (buf, len << hw->shift, 0x80);
 267         break;
 268
 269     case AUD_FMT_U16:
 270         {
 271             unsigned int i;
 272             uint16_t *p = buf;
 273             int shift = hw->nchannels - 1;
 274
 275             for (i = 0; i < len << shift; i++) {
 276                 p[i] = INT16_MAX;
 277             }
 278         }
 279         break;
 280     }
 281 }
 282
 283 int pcm_hw_write (SWVoice *sw, void *buf, int size)
 284 {
 285     int hwsamples, samples, isamp, osamp, wpos, live, dead, left, swlim, blck;
 286     int ret = 0, pos = 0;
 287     if (!sw)
 288         return size;
 289
 290     hwsamples = sw->hw->samples;
 291     samples = size >> sw->shift;
 292
 293     if (!sw->live) {
 294         sw->wpos = sw->hw->rpos;
 295     }
 296     wpos = sw->wpos;
 297     live = sw->live;
 298     dead = hwsamples - live;
 299     swlim = (dead * ((int64_t) INT_MAX)) / sw->ratio;
 300     swlim = audio_MIN (swlim, samples);
 301
 302     ldebug ("size=%d live=%d dead=%d swlim=%d wpos=%d\n",
 303            size, live, dead, swlim, wpos);
 304     if (swlim)
 305         sw->conv (sw->buf, buf, swlim);
 306
 307     while (swlim) {
 308         dead = hwsamples - live;
 309         left = hwsamples - wpos;
 310         blck = audio_MIN (dead, left);
 311         if (!blck) {
 312             /* dolog ("swlim=%d\n", swlim); */
 313             break;
 314         }
 315         isamp = swlim;
 316         osamp = blck;
 317         st_rate_flow (sw->rate, sw->buf + pos, sw->hw->mix_buf + wpos, &isamp, &osamp);
 318         ret += isamp;
 319         swlim -= isamp;
 320         pos += isamp;
 321         live += osamp;
 322         wpos = (wpos + osamp) % hwsamples;
 323     }
 324
 325     sw->wpos = wpos;
 326     sw->live = live;
 327     return ret << sw->shift;
 328 }
 329
 330 int pcm_hw_init (HWVoice *hw, int freq, int nchannels, audfmt_e fmt)
 331 {
 332     int sign = 0, bits = 8;
 333
 334     pcm_hw_fini (hw);
 335     ldebug ("pcm_hw_init: %d %d %d\n", freq, nchannels, fmt);
 336     if (hw->pcm_ops->init (hw, freq, nchannels, fmt)) {
 337         memset (hw, 0, audio_state.drv->voice_size);
 338         return -1;
 339     }
 340
 341     switch (hw->fmt) {
 342     case AUD_FMT_S8:
 343         sign = 1;
 344     case AUD_FMT_U8:
 345         break;
 346
 347     case AUD_FMT_S16:
 348         sign = 1;
 349     case AUD_FMT_U16:
 350         bits = 16;
 351         break;
 352     }
 353
 354     hw->nb_voices = 0;
 355     hw->active = 1;
 356     hw->shift = (hw->nchannels == 2) + (bits == 16);
 357     hw->bytes_per_second = hw->freq << hw->shift;
 358     hw->align = (1 << hw->shift) - 1;
 359     hw->samples = hw->bufsize >> hw->shift;
 360     hw->clip = mixeng_clip[hw->nchannels == 2][sign][bits == 16];
 361     if (pcm_hw_alloc_resources (hw)) {
 362         pcm_hw_fini (hw);
 363         return -1;
 364     }
 365     return 0;
 366 }
 367
 368 static int dist (void *hw)
 369 {
 370     if (hw) {
 371         return (((uint8_t *) hw - (uint8_t *) hw_voices)
 372                 / audio_state.voice_size) + 1;
 373     }
 374     else {
 375         return 0;
 376     }
 377 }
 378
 379 #define ADVANCE(hw) hw ? advance (hw, audio_state.voice_size) : hw_voices
 380
 381 HWVoice *pcm_hw_find_any (HWVoice *hw)
 382 {
 383     int i = dist (hw);
 384     for (; i < audio_state.nb_hw_voices; i++) {
 385         hw = ADVANCE (hw);
 386         return hw;
 387     }
 388     return NULL;
 389 }
 390
 391 HWVoice *pcm_hw_find_any_active (HWVoice *hw)
 392 {
 393     int i = dist (hw);
 394     for (; i < audio_state.nb_hw_voices; i++) {
 395         hw = ADVANCE (hw);
 396         if (hw->active)
 397             return hw;
 398     }
 399     return NULL;
 400 }
 401
 402 HWVoice *pcm_hw_find_any_active_enabled (HWVoice *hw)
 403 {
 404     int i = dist (hw);
 405     for (; i < audio_state.nb_hw_voices; i++) {
 406         hw = ADVANCE (hw);
 407         if (hw->active && hw->enabled)
 408             return hw;
 409     }
 410     return NULL;
 411 }
 412
 413 HWVoice *pcm_hw_find_any_passive (HWVoice *hw)
 414 {
 415     int i = dist (hw);
 416     for (; i < audio_state.nb_hw_voices; i++) {
 417         hw = ADVANCE (hw);
 418         if (!hw->active)
 419             return hw;
 420     }
 421     return NULL;
 422 }
 423
 424 HWVoice *pcm_hw_find_specific (HWVoice *hw, int freq,
 425                                int nchannels, audfmt_e fmt)
 426 {
 427     while ((hw = pcm_hw_find_any_active (hw))) {
 428         if (hw->freq == freq &&
 429             hw->nchannels == nchannels &&
 430             hw->fmt == fmt)
 431             return hw;
 432     }
 433     return NULL;
 434 }
 435
 436 HWVoice *pcm_hw_add (int freq, int nchannels, audfmt_e fmt)
 437 {
 438     HWVoice *hw;
 439
 440     if (audio_state.fixed_format) {
 441         freq = audio_state.fixed_freq;
 442         nchannels = audio_state.fixed_channels;
 443         fmt = audio_state.fixed_fmt;
 444     }
 445
 446     hw = pcm_hw_find_specific (NULL, freq, nchannels, fmt);
 447
 448     if (hw)
 449         return hw;
 450
 451     hw = pcm_hw_find_any_passive (NULL);
 452     if (hw) {
 453         hw->pcm_ops = audio_state.drv->pcm_ops;
 454         if (!hw->pcm_ops)
 455             return NULL;
 456
 457         if (pcm_hw_init (hw, freq, nchannels, fmt)) {
 458             pcm_hw_gc (hw);
 459             return NULL;
 460         }
 461         else
 462             return hw;
 463     }
 464
 465     return pcm_hw_find_any (NULL);
 466 }
 467
 468 int pcm_hw_add_sw (HWVoice *hw, SWVoice *sw)
 469 {
 470     SWVoice **pvoice = qemu_mallocz ((hw->nb_voices + 1) * sizeof (sw));
 471     if (!pvoice)
 472         return -1;
 473
 474     memcpy (pvoice, hw->pvoice, hw->nb_voices * sizeof (sw));
 475     qemu_free (hw->pvoice);
 476     hw->pvoice = pvoice;
 477     hw->pvoice[hw->nb_voices++] = sw;
 478     return 0;
 479 }
 480
 481 int pcm_hw_del_sw (HWVoice *hw, SWVoice *sw)
 482 {
 483     int i, j;
 484     if (hw->nb_voices > 1) {
 485         SWVoice **pvoice = qemu_mallocz ((hw->nb_voices - 1) * sizeof (sw));
 486
 487         if (!pvoice) {
 488             dolog ("Can not maintain consistent state (not enough memory)\n");
 489             return -1;
 490         }
 491
 492         for (i = 0, j = 0; i < hw->nb_voices; i++) {
 493             if (j >= hw->nb_voices - 1) {
 494                 dolog ("Can not maintain consistent state "
 495                        "(invariant violated)\n");
 496                 return -1;
 497             }
 498             if (hw->pvoice[i] != sw)
 499                 pvoice[j++] = hw->pvoice[i];
 500         }
 501         qemu_free (hw->pvoice);
 502         hw->pvoice = pvoice;
 503         hw->nb_voices -= 1;
 504     }
 505     else {
 506         qemu_free (hw->pvoice);
 507         hw->pvoice = NULL;
 508         hw->nb_voices = 0;
 509     }
 510     return 0;
 511 }
 512
 513 SWVoice *pcm_create_voice_pair (int freq, int nchannels, audfmt_e fmt)
 514 {
 515     SWVoice *sw;
 516     HWVoice *hw;
 517
 518     sw = qemu_mallocz (sizeof (*sw));
 519     if (!sw)
 520         goto err1;
 521
 522     hw = pcm_hw_add (freq, nchannels, fmt);
 523     if (!hw)
 524         goto err2;
 525
 526     if (pcm_hw_add_sw (hw, sw))
 527         goto err3;
 528
 529     if (pcm_sw_init (sw, hw, freq, nchannels, fmt))
 530         goto err4;
 531
 532     return sw;
 533
 534 err4:
 535     pcm_hw_del_sw (hw, sw);
 536 err3:
 537     pcm_hw_gc (hw);
 538 err2:
 539     qemu_free (sw);
 540 err1:
 541     return NULL;
 542 }
 543
 544 SWVoice *AUD_open (SWVoice *sw, const char *name,
 545                    int freq, int nchannels, audfmt_e fmt)
 546 {
 547     if (!audio_state.drv) {
 548         return NULL;
 549     }
 550
 551     if (sw && freq == sw->freq && sw->nchannels == nchannels && sw->fmt == fmt) {
 552         return sw;
 553     }
 554
 555     if (sw) {
 556         ldebug ("Different format %s %d %d %d\n",
 557                 name,
 558                 sw->freq == freq,
 559                 sw->nchannels == nchannels,
 560                 sw->fmt == fmt);
 561     }
 562
 563     if (nchannels != 1 && nchannels != 2) {
 564         dolog ("Bogus channel count %d for voice %s\n", nchannels, name);
 565         return NULL;
 566     }
 567
 568     if (!audio_state.fixed_format && sw) {
 569         pcm_sw_fini (sw);
 570         pcm_hw_del_sw (sw->hw, sw);
 571         pcm_hw_gc (sw->hw);
 572         if (sw->name) {
 573             qemu_free (sw->name);
 574             sw->name = NULL;
 575         }
 576         qemu_free (sw);
 577         sw = NULL;
 578     }
 579
 580     if (sw) {
 581         HWVoice *hw = sw->hw;
 582         if (!hw) {
 583             dolog ("Internal logic error voice %s has no hardware store\n",
 584                    name);
 585             return sw;
 586         }
 587
 588         if (pcm_sw_init (sw, hw, freq, nchannels, fmt)) {
 589             pcm_sw_fini (sw);
 590             pcm_hw_del_sw (hw, sw);
 591             pcm_hw_gc (hw);
 592             if (sw->name) {
 593                 qemu_free (sw->name);
 594                 sw->name = NULL;
 595             }
 596             qemu_free (sw);
 597             return NULL;
 598         }
 599     }
 600     else {
 601         sw = pcm_create_voice_pair (freq, nchannels, fmt);
 602         if (!sw) {
 603             dolog ("Failed to create voice %s\n", name);
 604             return NULL;
 605         }
 606     }
 607
 608     if (sw->name) {
 609         qemu_free (sw->name);
 610         sw->name = NULL;
 611     }
 612     sw->name = qemu_strdup (name);
 613     return sw;
 614 }
 615
 616 void AUD_close (SWVoice *sw)
 617 {
 618     if (!sw)
 619         return;
 620
 621     pcm_sw_fini (sw);
 622     pcm_hw_del_sw (sw->hw, sw);
 623     pcm_hw_gc (sw->hw);
 624     if (sw->name) {
 625         qemu_free (sw->name);
 626         sw->name = NULL;
 627     }
 628     qemu_free (sw);
 629 }
 630
 631 int AUD_write (SWVoice *sw, void *buf, int size)
 632 {
 633     int bytes;
 634
 635     if (!sw->hw->enabled)
 636         dolog ("Writing to disabled voice %s\n", sw->name);
 637     bytes = sw->hw->pcm_ops->write (sw, buf, size);
 638     return bytes;
 639 }
 640
 641 void AUD_run (void)
 642 {
 643     HWVoice *hw = NULL;
 644
 645     while ((hw = pcm_hw_find_any_active_enabled (hw))) {
 646         int i;
 647         if (hw->pending_disable && pcm_hw_get_live (hw) <= 0) {
 648             hw->enabled = 0;
 649             hw->pcm_ops->ctl (hw, VOICE_DISABLE);
 650             for (i = 0; i < hw->nb_voices; i++) {
 651                 hw->pvoice[i]->live = 0;
 652                 /* hw->pvoice[i]->old_ticks = 0; */
 653             }
 654             continue;
 655         }
 656
 657         hw->pcm_ops->run (hw);
 658         assert (hw->rpos < hw->samples);
 659         for (i = 0; i < hw->nb_voices; i++) {
 660             SWVoice *sw = hw->pvoice[i];
 661             if (!sw->active && !sw->live && sw->old_ticks) {
 662                 int64_t delta = qemu_get_clock (vm_clock) - sw->old_ticks;
 663                 if (delta > audio_state.ticks_threshold) {
 664                     ldebug ("resetting old_ticks for %s\n", sw->name);
 665                     sw->old_ticks = 0;
 666                 }
 667             }
 668         }
 669     }
 670 }
 671
 672 int AUD_get_free (SWVoice *sw)
 673 {
 674     int free;
 675
 676     if (!sw)
 677         return 4096;
 678
 679     free = ((sw->hw->samples - sw->live) << sw->hw->shift) * sw->ratio
 680         / INT_MAX;
 681
 682     free &= ~sw->hw->align;
 683     if (!free) return 0;
 684
 685     return free;
 686 }
 687
 688 int AUD_get_buffer_size (SWVoice *sw)
 689 {
 690     return sw->hw->bufsize;
 691 }
 692
 693 void AUD_adjust (SWVoice *sw, int bytes)
 694 {
 695     if (!sw)
 696         return;
 697     sw->old_ticks += (ticks_per_sec * (int64_t) bytes) / sw->bytes_per_second;
 698 }
 699
 700 void AUD_reset (SWVoice *sw)
 701 {
 702     sw->active = 0;
 703     sw->old_ticks = 0;
 704 }
 705
 706 int AUD_calc_elapsed (SWVoice *sw)
 707 {
 708     int64_t now, delta, bytes;
 709     int dead, swlim;
 710
 711     if (!sw)
 712         return 0;
 713
 714     now = qemu_get_clock (vm_clock);
 715     delta = now - sw->old_ticks;
 716     bytes = (delta * sw->bytes_per_second) / ticks_per_sec;
 717     if (delta < 0) {
 718         dolog ("whoops delta(<0)=%lld\n", delta);
 719         return 0;
 720     }
 721
 722     dead = sw->hw->samples - sw->live;
 723     swlim = ((dead * (int64_t) INT_MAX) / sw->ratio);
 724
 725     if (bytes > swlim) {
 726         return swlim;
 727     }
 728     else {
 729         return bytes;
 730     }
 731 }
 732
 733 void AUD_enable (SWVoice *sw, int on)
 734 {
 735     int i;
 736     HWVoice *hw;
 737
 738     if (!sw)
 739         return;
 740
 741     hw = sw->hw;
 742     if (on) {
 743         if (!sw->live)
 744             sw->wpos = sw->hw->rpos;
 745         if (!sw->old_ticks) {
 746             sw->old_ticks = qemu_get_clock (vm_clock);
 747         }
 748     }
 749
 750     if (sw->active != on) {
 751         if (on) {
 752             hw->pending_disable = 0;
 753             if (!hw->enabled) {
 754                 hw->enabled = 1;
 755                 for (i = 0; i < hw->nb_voices; i++) {
 756                     ldebug ("resetting voice\n");
 757                     sw = hw->pvoice[i];
 758                     sw->old_ticks = qemu_get_clock (vm_clock);
 759                 }
 760                 hw->pcm_ops->ctl (hw, VOICE_ENABLE);
 761             }
 762         }
 763         else {
 764             if (hw->enabled && !hw->pending_disable) {
 765                 int nb_active = 0;
 766                 for (i = 0; i < hw->nb_voices; i++) {
 767                     nb_active += hw->pvoice[i]->active != 0;
 768                 }
 769
 770                 if (nb_active == 1) {
 771                     hw->pending_disable = 1;
 772                 }
 773             }
 774         }
 775         sw->active = on;
 776     }
 777 }
 778
 779 static struct audio_output_driver *drvtab[] = {
 780 #ifdef CONFIG_OSS
 781     &oss_output_driver,
 782 #endif
 783 #ifdef USE_FMOD_AUDIO
 784     &fmod_output_driver,
 785 #endif
 786 #ifdef CONFIG_SDL
 787     &sdl_output_driver,
 788 #endif
 789 #ifdef USE_WAV_AUDIO
 790     &wav_output_driver,
 791 #endif
 792 };
 793
 794 static int voice_init (struct audio_output_driver *drv)
 795 {
 796     audio_state.opaque = drv->init ();
 797     if (audio_state.opaque) {
 798         if (audio_state.nb_hw_voices > drv->max_voices) {
 799             dolog ("`%s' does not support %d multiple hardware channels\n"
 800                    "Resetting to %d\n",
 801                    drv->name, audio_state.nb_hw_voices, drv->max_voices);
 802             audio_state.nb_hw_voices = drv->max_voices;
 803         }
 804         hw_voices = qemu_mallocz (audio_state.nb_hw_voices * drv->voice_size);
 805         if (hw_voices) {
 806             audio_state.drv = drv;
 807             return 1;
 808         }
 809         else {
 810             dolog ("Not enough memory for %d `%s' voices (each %d bytes)\n",
 811                    audio_state.nb_hw_voices, drv->name, drv->voice_size);
 812             drv->fini (audio_state.opaque);
 813             return 0;
 814         }
 815     }
 816     else {
 817         dolog ("Could not init `%s' audio\n", drv->name);
 818         return 0;
 819     }
 820 }
 821
 822 static void audio_vm_stop_handler (void *opaque, int reason)
 823 {
 824     HWVoice *hw = NULL;
 825
 826     while ((hw = pcm_hw_find_any (hw))) {
 827         if (!hw->pcm_ops)
 828             continue;
 829
 830         hw->pcm_ops->ctl (hw, reason ? VOICE_ENABLE : VOICE_DISABLE);
 831     }
 832 }
 833
 834 static void audio_atexit (void)
 835 {
 836     HWVoice *hw = NULL;
 837
 838     while ((hw = pcm_hw_find_any (hw))) {
 839         if (!hw->pcm_ops)
 840             continue;
 841
 842         hw->pcm_ops->ctl (hw, VOICE_DISABLE);
 843         hw->pcm_ops->fini (hw);
 844     }
 845     audio_state.drv->fini (audio_state.opaque);
 846 }
 847
 848 static void audio_save (QEMUFile *f, void *opaque)
 849 {
 850 }
 851
 852 static int audio_load (QEMUFile *f, void *opaque, int version_id)
 853 {
 854     if (version_id != 1)
 855         return -EINVAL;
 856
 857     return 0;
 858 }
 859
 860 void AUD_init (void)
 861 {
 862     int i;
 863     int done = 0;
 864     const char *drvname;
 865
 866     audio_state.fixed_format =
 867         !!audio_get_conf_int (QC_FIXED_FORMAT, audio_state.fixed_format);
 868     audio_state.fixed_freq =
 869         audio_get_conf_int (QC_FIXED_FREQ, audio_state.fixed_freq);
 870     audio_state.nb_hw_voices =
 871         audio_get_conf_int (QC_VOICES, audio_state.nb_hw_voices);
 872
 873     if (audio_state.nb_hw_voices <= 0) {
 874         dolog ("Bogus number of voices %d, resetting to 1\n",
 875                audio_state.nb_hw_voices);
 876     }
 877
 878     drvname = audio_get_conf_str (QC_AUDIO_DRV, NULL);
 879     if (drvname) {
 880         int found = 0;
 881         for (i = 0; i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
 882             if (!strcmp (drvname, drvtab[i]->name)) {
 883                 done = voice_init (drvtab[i]);
 884                 found = 1;
 885                 break;
 886             }
 887         }
 888         if (!found) {
 889             dolog ("Unknown audio driver `%s'\n", drvname);
 890         }
 891     }
 892
 893     qemu_add_vm_stop_handler (audio_vm_stop_handler, NULL);
 894     atexit (audio_atexit);
 895
 896     if (!done) {
 897         for (i = 0; !done && i < sizeof (drvtab) / sizeof (drvtab[0]); i++) {
 898             if (drvtab[i]->can_be_default)
 899                 done = voice_init (drvtab[i]);
 900         }
 901     }
 902
 903     audio_state.ticks_threshold = ticks_per_sec / 50;
 904     audio_state.freq_threshold = 100;
 905
 906     register_savevm ("audio", 0, 1, audio_save, audio_load, NULL);
 907     if (!done) {
 908         dolog ("Can not initialize audio subsystem\n");
 909         return;
 910     }
 911 }