audio/dsoundaudio.c

   1 /*
   2  * QEMU DirectSound audio driver
   3  *
   4  * Copyright (c) 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
  25 /*
  26  * SEAL 1.07 by Carlos 'pel' Hasan was used as documentation
  27  */
  28
  29 #include "qemu/osdep.h"
  30 #include "audio.h"
  31
  32 #define AUDIO_CAP "dsound"
  33 #include "audio_int.h"
  34 #include "qemu/host-utils.h"
  35 #include "qemu/module.h"
  36
  37 #include <windows.h>
  38 #include <mmsystem.h>
  39 #include <objbase.h>
  40 #include <dsound.h>
  41
  42 #include "audio_win_int.h"
  43
  44 /* #define DEBUG_DSOUND */
  45
  46 typedef struct {
  47     LPDIRECTSOUND dsound;
  48     LPDIRECTSOUNDCAPTURE dsound_capture;
  49     struct audsettings settings;
  50     Audiodev *dev;
  51 } dsound;
  52
  53 typedef struct {
  54     HWVoiceOut hw;
  55     LPDIRECTSOUNDBUFFER dsound_buffer;
  56     bool first_time;
  57     dsound *s;
  58 } DSoundVoiceOut;
  59
  60 typedef struct {
  61     HWVoiceIn hw;
  62     LPDIRECTSOUNDCAPTUREBUFFER dsound_capture_buffer;
  63     bool first_time;
  64     dsound *s;
  65 } DSoundVoiceIn;
  66
  67 static void dsound_log_hresult (HRESULT hr)
  68 {
  69     const char *str = "BUG";
  70
  71     switch (hr) {
  72     case DS_OK:
  73         str = "The method succeeded";
  74         break;
  75 #ifdef DS_NO_VIRTUALIZATION
  76     case DS_NO_VIRTUALIZATION:
  77         str = "The buffer was created, but another 3D algorithm was substituted";
  78         break;
  79 #endif
  80 #ifdef DS_INCOMPLETE
  81     case DS_INCOMPLETE:
  82         str = "The method succeeded, but not all the optional effects were obtained";
  83         break;
  84 #endif
  85 #ifdef DSERR_ACCESSDENIED
  86     case DSERR_ACCESSDENIED:
  87         str = "The request failed because access was denied";
  88         break;
  89 #endif
  90 #ifdef DSERR_ALLOCATED
  91     case DSERR_ALLOCATED:
  92         str = "The request failed because resources, "
  93               "such as a priority level, were already in use "
  94               "by another caller";
  95         break;
  96 #endif
  97 #ifdef DSERR_ALREADYINITIALIZED
  98     case DSERR_ALREADYINITIALIZED:
  99         str = "The object is already initialized";
 100         break;
 101 #endif
 102 #ifdef DSERR_BADFORMAT
 103     case DSERR_BADFORMAT:
 104         str = "The specified wave format is not supported";
 105         break;
 106 #endif
 107 #ifdef DSERR_BADSENDBUFFERGUID
 108     case DSERR_BADSENDBUFFERGUID:
 109         str = "The GUID specified in an audiopath file "
 110               "does not match a valid mix-in buffer";
 111         break;
 112 #endif
 113 #ifdef DSERR_BUFFERLOST
 114     case DSERR_BUFFERLOST:
 115         str = "The buffer memory has been lost and must be restored";
 116         break;
 117 #endif
 118 #ifdef DSERR_BUFFERTOOSMALL
 119     case DSERR_BUFFERTOOSMALL:
 120         str = "The buffer size is not great enough to "
 121               "enable effects processing";
 122         break;
 123 #endif
 124 #ifdef DSERR_CONTROLUNAVAIL
 125     case DSERR_CONTROLUNAVAIL:
 126         str = "The buffer control (volume, pan, and so on) "
 127               "requested by the caller is not available. "
 128               "Controls must be specified when the buffer is created, "
 129               "using the dwFlags member of DSBUFFERDESC";
 130         break;
 131 #endif
 132 #ifdef DSERR_DS8_REQUIRED
 133     case DSERR_DS8_REQUIRED:
 134         str = "A DirectSound object of class CLSID_DirectSound8 or later "
 135               "is required for the requested functionality. "
 136               "For more information, see IDirectSound8 Interface";
 137         break;
 138 #endif
 139 #ifdef DSERR_FXUNAVAILABLE
 140     case DSERR_FXUNAVAILABLE:
 141         str = "The effects requested could not be found on the system, "
 142               "or they are in the wrong order or in the wrong location; "
 143               "for example, an effect expected in hardware "
 144               "was found in software";
 145         break;
 146 #endif
 147 #ifdef DSERR_GENERIC
 148     case DSERR_GENERIC:
 149         str = "An undetermined error occurred inside the DirectSound subsystem";
 150         break;
 151 #endif
 152 #ifdef DSERR_INVALIDCALL
 153     case DSERR_INVALIDCALL:
 154         str = "This function is not valid for the current state of this object";
 155         break;
 156 #endif
 157 #ifdef DSERR_INVALIDPARAM
 158     case DSERR_INVALIDPARAM:
 159         str = "An invalid parameter was passed to the returning function";
 160         break;
 161 #endif
 162 #ifdef DSERR_NOAGGREGATION
 163     case DSERR_NOAGGREGATION:
 164         str = "The object does not support aggregation";
 165         break;
 166 #endif
 167 #ifdef DSERR_NODRIVER
 168     case DSERR_NODRIVER:
 169         str = "No sound driver is available for use, "
 170               "or the given GUID is not a valid DirectSound device ID";
 171         break;
 172 #endif
 173 #ifdef DSERR_NOINTERFACE
 174     case DSERR_NOINTERFACE:
 175         str = "The requested COM interface is not available";
 176         break;
 177 #endif
 178 #ifdef DSERR_OBJECTNOTFOUND
 179     case DSERR_OBJECTNOTFOUND:
 180         str = "The requested object was not found";
 181         break;
 182 #endif
 183 #ifdef DSERR_OTHERAPPHASPRIO
 184     case DSERR_OTHERAPPHASPRIO:
 185         str = "Another application has a higher priority level, "
 186               "preventing this call from succeeding";
 187         break;
 188 #endif
 189 #ifdef DSERR_OUTOFMEMORY
 190     case DSERR_OUTOFMEMORY:
 191         str = "The DirectSound subsystem could not allocate "
 192                "sufficient memory to complete the caller's request";
 193         break;
 194 #endif
 195 #ifdef DSERR_PRIOLEVELNEEDED
 196     case DSERR_PRIOLEVELNEEDED:
 197         str = "A cooperative level of DSSCL_PRIORITY or higher is required";
 198         break;
 199 #endif
 200 #ifdef DSERR_SENDLOOP
 201     case DSERR_SENDLOOP:
 202         str = "A circular loop of send effects was detected";
 203         break;
 204 #endif
 205 #ifdef DSERR_UNINITIALIZED
 206     case DSERR_UNINITIALIZED:
 207         str = "The Initialize method has not been called "
 208               "or has not been called successfully "
 209               "before other methods were called";
 210         break;
 211 #endif
 212 #ifdef DSERR_UNSUPPORTED
 213     case DSERR_UNSUPPORTED:
 214         str = "The function called is not supported at this time";
 215         break;
 216 #endif
 217     default:
 218         AUD_log (AUDIO_CAP, "Reason: Unknown (HRESULT 0x%lx)\n", hr);
 219         return;
 220     }
 221
 222     AUD_log (AUDIO_CAP, "Reason: %s\n", str);
 223 }
 224
 225 static void G_GNUC_PRINTF (2, 3) dsound_logerr (
 226     HRESULT hr,
 227     const char *fmt,
 228     ...
 229     )
 230 {
 231     va_list ap;
 232
 233     va_start (ap, fmt);
 234     AUD_vlog (AUDIO_CAP, fmt, ap);
 235     va_end (ap);
 236
 237     dsound_log_hresult (hr);
 238 }
 239
 240 static void G_GNUC_PRINTF (3, 4) dsound_logerr2 (
 241     HRESULT hr,
 242     const char *typ,
 243     const char *fmt,
 244     ...
 245     )
 246 {
 247     va_list ap;
 248
 249     AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
 250     va_start (ap, fmt);
 251     AUD_vlog (AUDIO_CAP, fmt, ap);
 252     va_end (ap);
 253
 254     dsound_log_hresult (hr);
 255 }
 256
 257 #ifdef DEBUG_DSOUND
 258 static void print_wave_format (WAVEFORMATEX *wfx)
 259 {
 260     dolog ("tag             = %d\n", wfx->wFormatTag);
 261     dolog ("nChannels       = %d\n", wfx->nChannels);
 262     dolog ("nSamplesPerSec  = %ld\n", wfx->nSamplesPerSec);
 263     dolog ("nAvgBytesPerSec = %ld\n", wfx->nAvgBytesPerSec);
 264     dolog ("nBlockAlign     = %d\n", wfx->nBlockAlign);
 265     dolog ("wBitsPerSample  = %d\n", wfx->wBitsPerSample);
 266     dolog ("cbSize          = %d\n", wfx->cbSize);
 267 }
 268 #endif
 269
 270 static int dsound_restore_out (LPDIRECTSOUNDBUFFER dsb, dsound *s)
 271 {
 272     HRESULT hr;
 273
 274     hr = IDirectSoundBuffer_Restore (dsb);
 275
 276     if (hr != DS_OK) {
 277         dsound_logerr (hr, "Could not restore playback buffer\n");
 278         return -1;
 279     }
 280     return 0;
 281 }
 282
 283 #include "dsound_template.h"
 284 #define DSBTYPE_IN
 285 #include "dsound_template.h"
 286 #undef DSBTYPE_IN
 287
 288 static int dsound_get_status_out (LPDIRECTSOUNDBUFFER dsb, DWORD *statusp,
 289                                   dsound *s)
 290 {
 291     HRESULT hr;
 292
 293     hr = IDirectSoundBuffer_GetStatus (dsb, statusp);
 294     if (FAILED (hr)) {
 295         dsound_logerr (hr, "Could not get playback buffer status\n");
 296         return -1;
 297     }
 298
 299     if (*statusp & DSBSTATUS_BUFFERLOST) {
 300         dsound_restore_out(dsb, s);
 301         return -1;
 302     }
 303
 304     return 0;
 305 }
 306
 307 static int dsound_get_status_in (LPDIRECTSOUNDCAPTUREBUFFER dscb,
 308                                  DWORD *statusp)
 309 {
 310     HRESULT hr;
 311
 312     hr = IDirectSoundCaptureBuffer_GetStatus (dscb, statusp);
 313     if (FAILED (hr)) {
 314         dsound_logerr (hr, "Could not get capture buffer status\n");
 315         return -1;
 316     }
 317
 318     return 0;
 319 }
 320
 321 static void dsound_clear_sample (HWVoiceOut *hw, LPDIRECTSOUNDBUFFER dsb,
 322                                  dsound *s)
 323 {
 324     int err;
 325     LPVOID p1, p2;
 326     DWORD blen1, blen2, len1, len2;
 327
 328     err = dsound_lock_out (
 329         dsb,
 330         &hw->info,
 331         0,
 332         hw->size_emul,
 333         &p1, &p2,
 334         &blen1, &blen2,
 335         1,
 336         s
 337         );
 338     if (err) {
 339         return;
 340     }
 341
 342     len1 = blen1 / hw->info.bytes_per_frame;
 343     len2 = blen2 / hw->info.bytes_per_frame;
 344
 345 #ifdef DEBUG_DSOUND
 346     dolog ("clear %p,%ld,%ld %p,%ld,%ld\n",
 347            p1, blen1, len1,
 348            p2, blen2, len2);
 349 #endif
 350
 351     if (p1 && len1) {
 352         audio_pcm_info_clear_buf (&hw->info, p1, len1);
 353     }
 354
 355     if (p2 && len2) {
 356         audio_pcm_info_clear_buf (&hw->info, p2, len2);
 357     }
 358
 359     dsound_unlock_out (dsb, p1, p2, blen1, blen2);
 360 }
 361
 362 static int dsound_set_cooperative_level(dsound *s)
 363 {
 364     HRESULT hr;
 365     HWND hwnd;
 366
 367     hwnd = GetDesktopWindow();
 368     hr = IDirectSound_SetCooperativeLevel (
 369         s->dsound,
 370         hwnd,
 371         DSSCL_PRIORITY
 372         );
 373
 374     if (FAILED (hr)) {
 375         dsound_logerr (hr, "Could not set cooperative level for window %p\n",
 376                        hwnd);
 377         return -1;
 378     }
 379
 380     return 0;
 381 }
 382
 383 static void dsound_enable_out(HWVoiceOut *hw, bool enable)
 384 {
 385     HRESULT hr;
 386     DWORD status;
 387     DSoundVoiceOut *ds = (DSoundVoiceOut *) hw;
 388     LPDIRECTSOUNDBUFFER dsb = ds->dsound_buffer;
 389     dsound *s = ds->s;
 390
 391     if (!dsb) {
 392         dolog ("Attempt to control voice without a buffer\n");
 393         return;
 394     }
 395
 396     if (enable) {
 397         if (dsound_get_status_out (dsb, &status, s)) {
 398             return;
 399         }
 400
 401         if (status & DSBSTATUS_PLAYING) {
 402             dolog ("warning: Voice is already playing\n");
 403             return;
 404         }
 405
 406         dsound_clear_sample (hw, dsb, s);
 407
 408         hr = IDirectSoundBuffer_Play (dsb, 0, 0, DSBPLAY_LOOPING);
 409         if (FAILED (hr)) {
 410             dsound_logerr (hr, "Could not start playing buffer\n");
 411             return;
 412         }
 413     } else {
 414         if (dsound_get_status_out (dsb, &status, s)) {
 415             return;
 416         }
 417
 418         if (status & DSBSTATUS_PLAYING) {
 419             hr = IDirectSoundBuffer_Stop (dsb);
 420             if (FAILED (hr)) {
 421                 dsound_logerr (hr, "Could not stop playing buffer\n");
 422                 return;
 423             }
 424         } else {
 425             dolog ("warning: Voice is not playing\n");
 426         }
 427     }
 428 }
 429
 430 static size_t dsound_buffer_get_free(HWVoiceOut *hw)
 431 {
 432     DSoundVoiceOut *ds = (DSoundVoiceOut *) hw;
 433     LPDIRECTSOUNDBUFFER dsb = ds->dsound_buffer;
 434     HRESULT hr;
 435     DWORD ppos, wpos;
 436
 437     hr = IDirectSoundBuffer_GetCurrentPosition(
 438         dsb, &ppos, ds->first_time ? &wpos : NULL);
 439     if (FAILED(hr)) {
 440         dsound_logerr(hr, "Could not get playback buffer position\n");
 441         return 0;
 442     }
 443
 444     if (ds->first_time) {
 445         hw->pos_emul = wpos;
 446         ds->first_time = false;
 447     }
 448
 449     return audio_ring_dist(ppos, hw->pos_emul, hw->size_emul);
 450 }
 451
 452 static void *dsound_get_buffer_out(HWVoiceOut *hw, size_t *size)
 453 {
 454     DSoundVoiceOut *ds = (DSoundVoiceOut *)hw;
 455     LPDIRECTSOUNDBUFFER dsb = ds->dsound_buffer;
 456     DWORD act_size;
 457     size_t req_size;
 458     int err;
 459     void *ret;
 460
 461     req_size = MIN(*size, hw->size_emul - hw->pos_emul);
 462     assert(req_size > 0);
 463
 464     err = dsound_lock_out(dsb, &hw->info, hw->pos_emul, req_size, &ret, NULL,
 465                           &act_size, NULL, false, ds->s);
 466     if (err) {
 467         dolog("Failed to lock buffer\n");
 468         *size = 0;
 469         return NULL;
 470     }
 471
 472     *size = act_size;
 473     return ret;
 474 }
 475
 476 static size_t dsound_put_buffer_out(HWVoiceOut *hw, void *buf, size_t len)
 477 {
 478     DSoundVoiceOut *ds = (DSoundVoiceOut *) hw;
 479     LPDIRECTSOUNDBUFFER dsb = ds->dsound_buffer;
 480     int err = dsound_unlock_out(dsb, buf, NULL, len, 0);
 481
 482     if (err) {
 483         dolog("Failed to unlock buffer!!\n");
 484         return 0;
 485     }
 486     hw->pos_emul = (hw->pos_emul + len) % hw->size_emul;
 487
 488     return len;
 489 }
 490
 491 static void dsound_enable_in(HWVoiceIn *hw, bool enable)
 492 {
 493     HRESULT hr;
 494     DWORD status;
 495     DSoundVoiceIn *ds = (DSoundVoiceIn *) hw;
 496     LPDIRECTSOUNDCAPTUREBUFFER dscb = ds->dsound_capture_buffer;
 497
 498     if (!dscb) {
 499         dolog ("Attempt to control capture voice without a buffer\n");
 500         return;
 501     }
 502
 503     if (enable) {
 504         if (dsound_get_status_in (dscb, &status)) {
 505             return;
 506         }
 507
 508         if (status & DSCBSTATUS_CAPTURING) {
 509             dolog ("warning: Voice is already capturing\n");
 510             return;
 511         }
 512
 513         /* clear ?? */
 514
 515         hr = IDirectSoundCaptureBuffer_Start (dscb, DSCBSTART_LOOPING);
 516         if (FAILED (hr)) {
 517             dsound_logerr (hr, "Could not start capturing\n");
 518             return;
 519         }
 520     } else {
 521         if (dsound_get_status_in (dscb, &status)) {
 522             return;
 523         }
 524
 525         if (status & DSCBSTATUS_CAPTURING) {
 526             hr = IDirectSoundCaptureBuffer_Stop (dscb);
 527             if (FAILED (hr)) {
 528                 dsound_logerr (hr, "Could not stop capturing\n");
 529                 return;
 530             }
 531         } else {
 532             dolog ("warning: Voice is not capturing\n");
 533         }
 534     }
 535 }
 536
 537 static void *dsound_get_buffer_in(HWVoiceIn *hw, size_t *size)
 538 {
 539     DSoundVoiceIn *ds = (DSoundVoiceIn *) hw;
 540     LPDIRECTSOUNDCAPTUREBUFFER dscb = ds->dsound_capture_buffer;
 541     HRESULT hr;
 542     DWORD rpos, act_size;
 543     size_t req_size;
 544     int err;
 545     void *ret;
 546
 547     hr = IDirectSoundCaptureBuffer_GetCurrentPosition(dscb, NULL, &rpos);
 548     if (FAILED(hr)) {
 549         dsound_logerr(hr, "Could not get capture buffer position\n");
 550         *size = 0;
 551         return NULL;
 552     }
 553
 554     if (ds->first_time) {
 555         hw->pos_emul = rpos;
 556         ds->first_time = false;
 557     }
 558
 559     req_size = audio_ring_dist(rpos, hw->pos_emul, hw->size_emul);
 560     req_size = MIN(*size, MIN(req_size, hw->size_emul - hw->pos_emul));
 561
 562     if (req_size == 0) {
 563         *size = 0;
 564         return NULL;
 565     }
 566
 567     err = dsound_lock_in(dscb, &hw->info, hw->pos_emul, req_size, &ret, NULL,
 568                          &act_size, NULL, false, ds->s);
 569     if (err) {
 570         dolog("Failed to lock buffer\n");
 571         *size = 0;
 572         return NULL;
 573     }
 574
 575     *size = act_size;
 576     return ret;
 577 }
 578
 579 static void dsound_put_buffer_in(HWVoiceIn *hw, void *buf, size_t len)
 580 {
 581     DSoundVoiceIn *ds = (DSoundVoiceIn *) hw;
 582     LPDIRECTSOUNDCAPTUREBUFFER dscb = ds->dsound_capture_buffer;
 583     int err = dsound_unlock_in(dscb, buf, NULL, len, 0);
 584
 585     if (err) {
 586         dolog("Failed to unlock buffer!!\n");
 587         return;
 588     }
 589     hw->pos_emul = (hw->pos_emul + len) % hw->size_emul;
 590 }
 591
 592 static void dsound_audio_fini (void *opaque)
 593 {
 594     HRESULT hr;
 595     dsound *s = opaque;
 596
 597     if (!s->dsound) {
 598         g_free(s);
 599         return;
 600     }
 601
 602     hr = IDirectSound_Release (s->dsound);
 603     if (FAILED (hr)) {
 604         dsound_logerr (hr, "Could not release DirectSound\n");
 605     }
 606     s->dsound = NULL;
 607
 608     if (!s->dsound_capture) {
 609         g_free(s);
 610         return;
 611     }
 612
 613     hr = IDirectSoundCapture_Release (s->dsound_capture);
 614     if (FAILED (hr)) {
 615         dsound_logerr (hr, "Could not release DirectSoundCapture\n");
 616     }
 617     s->dsound_capture = NULL;
 618
 619     g_free(s);
 620 }
 621
 622 static void *dsound_audio_init(Audiodev *dev, Error **errp)
 623 {
 624     int err;
 625     HRESULT hr;
 626     dsound *s = g_new0(dsound, 1);
 627     AudiodevDsoundOptions *dso;
 628
 629     assert(dev->driver == AUDIODEV_DRIVER_DSOUND);
 630     s->dev = dev;
 631     dso = &dev->u.dsound;
 632
 633     if (!dso->has_latency) {
 634         dso->has_latency = true;
 635         dso->latency = 10000; /* 10 ms */
 636     }
 637
 638     hr = CoInitialize (NULL);
 639     if (FAILED (hr)) {
 640         dsound_logerr (hr, "Could not initialize COM\n");
 641         g_free(s);
 642         return NULL;
 643     }
 644
 645     hr = CoCreateInstance (
 646         &CLSID_DirectSound,
 647         NULL,
 648         CLSCTX_ALL,
 649         &IID_IDirectSound,
 650         (void **) &s->dsound
 651         );
 652     if (FAILED (hr)) {
 653         dsound_logerr (hr, "Could not create DirectSound instance\n");
 654         g_free(s);
 655         return NULL;
 656     }
 657
 658     hr = IDirectSound_Initialize (s->dsound, NULL);
 659     if (FAILED (hr)) {
 660         dsound_logerr (hr, "Could not initialize DirectSound\n");
 661
 662         hr = IDirectSound_Release (s->dsound);
 663         if (FAILED (hr)) {
 664             dsound_logerr (hr, "Could not release DirectSound\n");
 665         }
 666         g_free(s);
 667         return NULL;
 668     }
 669
 670     hr = CoCreateInstance (
 671         &CLSID_DirectSoundCapture,
 672         NULL,
 673         CLSCTX_ALL,
 674         &IID_IDirectSoundCapture,
 675         (void **) &s->dsound_capture
 676         );
 677     if (FAILED (hr)) {
 678         dsound_logerr (hr, "Could not create DirectSoundCapture instance\n");
 679     } else {
 680         hr = IDirectSoundCapture_Initialize (s->dsound_capture, NULL);
 681         if (FAILED (hr)) {
 682             dsound_logerr (hr, "Could not initialize DirectSoundCapture\n");
 683
 684             hr = IDirectSoundCapture_Release (s->dsound_capture);
 685             if (FAILED (hr)) {
 686                 dsound_logerr (hr, "Could not release DirectSoundCapture\n");
 687             }
 688             s->dsound_capture = NULL;
 689         }
 690     }
 691
 692     err = dsound_set_cooperative_level(s);
 693     if (err) {
 694         dsound_audio_fini (s);
 695         return NULL;
 696     }
 697
 698     return s;
 699 }
 700
 701 static struct audio_pcm_ops dsound_pcm_ops = {
 702     .init_out = dsound_init_out,
 703     .fini_out = dsound_fini_out,
 704     .write    = audio_generic_write,
 705     .buffer_get_free = dsound_buffer_get_free,
 706     .get_buffer_out = dsound_get_buffer_out,
 707     .put_buffer_out = dsound_put_buffer_out,
 708     .enable_out = dsound_enable_out,
 709
 710     .init_in  = dsound_init_in,
 711     .fini_in  = dsound_fini_in,
 712     .read     = audio_generic_read,
 713     .get_buffer_in = dsound_get_buffer_in,
 714     .put_buffer_in = dsound_put_buffer_in,
 715     .enable_in = dsound_enable_in,
 716 };
 717
 718 static struct audio_driver dsound_audio_driver = {
 719     .name           = "dsound",
 720     .descr          = "DirectSound http://wikipedia.org/wiki/DirectSound",
 721     .init           = dsound_audio_init,
 722     .fini           = dsound_audio_fini,
 723     .pcm_ops        = &dsound_pcm_ops,
 724     .max_voices_out = INT_MAX,
 725     .max_voices_in  = 1,
 726     .voice_size_out = sizeof (DSoundVoiceOut),
 727     .voice_size_in  = sizeof (DSoundVoiceIn)
 728 };
 729
 730 static void register_audio_dsound(void)
 731 {
 732     audio_driver_register(&dsound_audio_driver);
 733 }
 734 type_init(register_audio_dsound);