audio: Don't trust audio drivers to drain pending audio.

This tends to be a frequent spot where drivers hang, and the waits were
often unreliable in any case.

Instead, our audio thread now alerts the driver that we're done streaming audio
(which currently XAudio2 uses to alert the system not to warn about the
impending underflow) and then SDL_Delay()'s for a duration that's reasonable
to drain the DMA buffers before closing the device.

src/audio/SDL_audio.c

@@ -191,11 +191,6 @@ SDL_AudioGetDeviceBuf_Default(_THIS)
     return NULL;
 }
 
-static void
-SDL_AudioWaitDone_Default(_THIS)
-{                               /* no-op. */
-}
-
 static int
 SDL_AudioCaptureFromDevice_Default(_THIS, void *buffer, int buflen)
 {
@@ -207,6 +202,11 @@ SDL_AudioFlushCapture_Default(_THIS)
 {                               /* no-op. */
 }
 
+static void
+SDL_AudioPrepareToClose_Default(_THIS)
+{                               /* no-op. */
+}
+
 static void
 SDL_AudioCloseDevice_Default(_THIS)
 {                               /* no-op. */
@@ -292,9 +292,9 @@ finish_audio_entry_points_init(void)
     FILL_STUB(PlayDevice);
     FILL_STUB(GetPendingBytes);
     FILL_STUB(GetDeviceBuf);
-    FILL_STUB(WaitDone);
     FILL_STUB(CaptureFromDevice);
     FILL_STUB(FlushCapture);
+    FILL_STUB(PrepareToClose);
     FILL_STUB(CloseDevice);
     FILL_STUB(LockDevice);
     FILL_STUB(UnlockDevice);
@@ -715,6 +715,9 @@ SDL_FinalizeAudioDevice(SDL_AudioDevice *device)
         return;
     }
 
+    SDL_AtomicSet(&device->shutdown, 1);  /* just in case. */
+    SDL_AtomicSet(&device->enabled, 0);
+
     /* lock/unlock here so we don't race if the audio thread saw the shutdown
        var without locking, and the thread that requested shutdown is now
        trying to unlock the mutex while we destroy it. Threading is hard. */
@@ -811,9 +814,10 @@ SDL_RunAudio(void *devicep)
         }
     }
 
+    current_audio.impl.PrepareToClose(device);
+
     /* Wait for the audio to drain. */
-    /* !!! FIXME: can we rename this WaitDrain? */
-    current_audio.impl.WaitDone(device);
+    SDL_Delay(((device->spec.samples * 1000) / device->spec.freq) * 2);
 
     SDL_FinalizeAudioDevice(device);
 
@@ -1153,7 +1157,7 @@ close_audio_device(SDL_AudioDevice * device)
 
         if (!device->iscapture) {
             const SDL_AudioSpec *spec = &device->spec;
-            delay = ((spec.samples * 1000) / spec.freq) * 2;
+            delay = ((spec->samples * 1000) / spec->freq) * 2;
         }
 
         /* Lock to make sure an audio callback doesn't fire after we return.

src/audio/SDL_sysaudio.h

@@ -79,9 +79,9 @@ typedef struct SDL_AudioDriverImpl
     void (*PlayDevice) (_THIS);
     int (*GetPendingBytes) (_THIS);
     Uint8 *(*GetDeviceBuf) (_THIS);
-    void (*WaitDone) (_THIS);
     int (*CaptureFromDevice) (_THIS, void *buffer, int buflen);
     void (*FlushCapture) (_THIS);
+    void (*PrepareToClose) (_THIS);  /**< Called between run and draining wait for playback devices */
     void (*CloseDevice) (_THIS);
     void (*LockDevice) (_THIS);
     void (*UnlockDevice) (_THIS);

src/audio/arts/SDL_artsaudio.c

@@ -185,13 +185,6 @@ ARTS_PlayDevice(_THIS)
 #endif
 }
 
-static void
-ARTS_WaitDone(_THIS)
-{
-    /* !!! FIXME: camp here until buffer drains... SDL_Delay(???); */
-}
-
-
 static Uint8 *
 ARTS_GetDeviceBuf(_THIS)
 {
@@ -356,7 +349,6 @@ ARTS_Init(SDL_AudioDriverImpl * impl)
     impl->WaitDevice = ARTS_WaitDevice;
     impl->GetDeviceBuf = ARTS_GetDeviceBuf;
     impl->CloseDevice = ARTS_CloseDevice;
-    impl->WaitDone = ARTS_WaitDone;
     impl->Deinitialize = ARTS_Deinitialize;
     impl->OnlyHasDefaultOutputDevice = 1;
 

src/audio/directsound/SDL_directsound.c

@@ -307,22 +307,6 @@ DSOUND_GetDeviceBuf(_THIS)
     return (this->hidden->locked_buf);
 }
 
-static void
-DSOUND_WaitDone(_THIS)
-{
-    Uint8 *stream = DSOUND_GetDeviceBuf(this);
-
-    /* Wait for the playing chunk to finish */
-    if (stream != NULL) {
-        SDL_memset(stream, this->spec.silence, this->spec.size);
-        DSOUND_PlayDevice(this);
-    }
-    DSOUND_WaitDevice(this);
-
-    /* Stop the looping sound buffer */
-    IDirectSoundBuffer_Stop(this->hidden->mixbuf);
-}
-
 static int
 DSOUND_CaptureFromDevice(_THIS, void *buffer, int buflen)
 {
@@ -600,7 +584,6 @@ DSOUND_Init(SDL_AudioDriverImpl * impl)
     impl->OpenDevice = DSOUND_OpenDevice;
     impl->PlayDevice = DSOUND_PlayDevice;
     impl->WaitDevice = DSOUND_WaitDevice;
-    impl->WaitDone = DSOUND_WaitDone;
     impl->GetDeviceBuf = DSOUND_GetDeviceBuf;
     impl->CaptureFromDevice = DSOUND_CaptureFromDevice;
     impl->FlushCapture = DSOUND_FlushCapture;

src/audio/fusionsound/SDL_fsaudio.c

@@ -151,13 +151,6 @@ SDL_FS_PlayDevice(_THIS)
 #endif
 }
 
-static void
-SDL_FS_WaitDone(_THIS)
-{
-    this->hidden->stream->Wait(this->hidden->stream,
-                               this->hidden->mixsamples * FUSION_BUFFERS);
-}
-
 
 static Uint8 *
 SDL_FS_GetDeviceBuf(_THIS)
@@ -319,7 +312,6 @@ SDL_FS_Init(SDL_AudioDriverImpl * impl)
     impl->WaitDevice = SDL_FS_WaitDevice;
     impl->GetDeviceBuf = SDL_FS_GetDeviceBuf;
     impl->CloseDevice = SDL_FS_CloseDevice;
-    impl->WaitDone = SDL_FS_WaitDone;
     impl->Deinitialize = SDL_FS_Deinitialize;
     impl->OnlyHasDefaultOutputDevice = 1;
 

src/audio/psp/SDL_pspaudio.c

@@ -152,7 +152,6 @@ PSPAUDIO_Init(SDL_AudioDriverImpl * impl)
     impl->PlayDevice = PSPAUDIO_PlayDevice;
     impl->WaitDevice = PSPAUDIO_WaitDevice;
     impl->GetDeviceBuf = PSPAUDIO_GetDeviceBuf;
-    impl->WaitDone = PSPAUDIO_WaitDevice;
     impl->CloseDevice = PSPAUDIO_CloseDevice;
     impl->ThreadInit = PSPAUDIO_ThreadInit;
 

src/audio/pulseaudio/SDL_pulseaudio.c

@@ -368,28 +368,6 @@ PULSEAUDIO_PlayDevice(_THIS)
     }
 }
 
-static void
-PULSEAUDIO_WaitDone(_THIS)
-{
-    if (SDL_AtomicGet(&this->enabled)) {
-        struct SDL_PrivateAudioData *h = this->hidden;
-        pa_operation *o = PULSEAUDIO_pa_stream_drain(h->stream, stream_operation_complete_no_op, NULL);
-        if (o) {
-            while (PULSEAUDIO_pa_operation_get_state(o) != PA_OPERATION_DONE) {
-                if (PULSEAUDIO_pa_context_get_state(h->context) != PA_CONTEXT_READY ||
-                    PULSEAUDIO_pa_stream_get_state(h->stream) != PA_STREAM_READY ||
-                    PULSEAUDIO_pa_mainloop_iterate(h->mainloop, 1, NULL) < 0) {
-                    PULSEAUDIO_pa_operation_cancel(o);
-                    break;
-                }
-            }
-            PULSEAUDIO_pa_operation_unref(o);
-        }
-    }
-}
-
-
-
 static Uint8 *
 PULSEAUDIO_GetDeviceBuf(_THIS)
 {
@@ -776,7 +754,6 @@ PULSEAUDIO_Init(SDL_AudioDriverImpl * impl)
     impl->WaitDevice = PULSEAUDIO_WaitDevice;
     impl->GetDeviceBuf = PULSEAUDIO_GetDeviceBuf;
     impl->CloseDevice = PULSEAUDIO_CloseDevice;
-    impl->WaitDone = PULSEAUDIO_WaitDone;
     impl->Deinitialize = PULSEAUDIO_Deinitialize;
     impl->CaptureFromDevice = PULSEAUDIO_CaptureFromDevice;
     impl->FlushCapture = PULSEAUDIO_FlushCapture;

src/audio/qsa/SDL_qsa_audio.c

@@ -708,24 +708,6 @@ QSA_DetectDevices(void)
     }
 }
 
-static void
-QSA_WaitDone(_THIS)
-{
-    if (!this->hidden->iscapture) {
-        if (this->hidden->audio_handle != NULL) {
-            /* Wait till last fragment is played and stop channel */
-            snd_pcm_plugin_flush(this->hidden->audio_handle,
-                                 SND_PCM_CHANNEL_PLAYBACK);
-        }
-    } else {
-        if (this->hidden->audio_handle != NULL) {
-            /* Discard all unread data and stop channel */
-            snd_pcm_plugin_flush(this->hidden->audio_handle,
-                                 SND_PCM_CHANNEL_CAPTURE);
-        }
-    }
-}
-
 static void
 QSA_Deinitialize(void)
 {
@@ -759,7 +741,6 @@ QSA_Init(SDL_AudioDriverImpl * impl)
     impl->PlayDevice = QSA_PlayDevice;
     impl->GetDeviceBuf = QSA_GetDeviceBuf;
     impl->CloseDevice = QSA_CloseDevice;
-    impl->WaitDone = QSA_WaitDone;
     impl->Deinitialize = QSA_Deinitialize;
     impl->LockDevice = NULL;
     impl->UnlockDevice = NULL;

src/audio/sndio/SDL_sndioaudio.c

@@ -170,16 +170,11 @@ SNDIO_GetDeviceBuf(_THIS)
     return this->hidden->mixbuf;
 }
 
-static void
-SNDIO_WaitDone(_THIS)
-{
-    SNDIO_sio_stop(this->hidden->dev);
-}
-
 static void
 SNDIO_CloseDevice(_THIS)
 {
     if ( this->hidden->dev != NULL ) {
+        SNDIO_sio_stop(this->hidden->dev);
         SNDIO_sio_close(this->hidden->dev);
     }
     SDL_free(this->hidden->mixbuf);
@@ -304,7 +299,6 @@ SNDIO_Init(SDL_AudioDriverImpl * impl)
     impl->WaitDevice = SNDIO_WaitDevice;
     impl->PlayDevice = SNDIO_PlayDevice;
     impl->GetDeviceBuf = SNDIO_GetDeviceBuf;
-    impl->WaitDone = SNDIO_WaitDone;
     impl->CloseDevice = SNDIO_CloseDevice;
     impl->Deinitialize = SNDIO_Deinitialize;
     impl->OnlyHasDefaultOutputDevice = 1;  /* !!! FIXME: sndio can handle multiple devices. */

src/audio/winmm/SDL_winmm.c

@@ -135,24 +135,6 @@ WINMM_PlayDevice(_THIS)
     this->hidden->next_buffer = (this->hidden->next_buffer + 1) % NUM_BUFFERS;
 }
 
-static void
-WINMM_WaitDone(_THIS)
-{
-    int i, left;
-
-    do {
-        left = NUM_BUFFERS;
-        for (i = 0; i < NUM_BUFFERS; ++i) {
-            if (this->hidden->wavebuf[i].dwFlags & WHDR_DONE) {
-                --left;
-            }
-        }
-        if (left > 0) {
-            SDL_Delay(100);
-        }
-    } while (left > 0);
-}
-
 static int
 WINMM_CaptureFromDevice(_THIS, void *buffer, int buflen)
 {
@@ -422,7 +404,6 @@ WINMM_Init(SDL_AudioDriverImpl * impl)
     impl->OpenDevice = WINMM_OpenDevice;
     impl->PlayDevice = WINMM_PlayDevice;
     impl->WaitDevice = WINMM_WaitDevice;
-    impl->WaitDone = WINMM_WaitDone;
     impl->GetDeviceBuf = WINMM_GetDeviceBuf;
     impl->CaptureFromDevice = WINMM_CaptureFromDevice;
     impl->FlushCapture = WINMM_FlushCapture;

src/audio/xaudio2/SDL_xaudio2.c

@@ -232,28 +232,14 @@ XAUDIO2_WaitDevice(_THIS)
 }
 
 static void
-XAUDIO2_WaitDone(_THIS)
+XAUDIO2_PrepareToClose(_THIS)
 {
     IXAudio2SourceVoice *source = this->hidden->source;
-    XAUDIO2_VOICE_STATE state;
-    SDL_assert(!SDL_AtomicGet(&this->enabled));  /* flag that stops playing. */
-    IXAudio2SourceVoice_Discontinuity(source);
-#if SDL_XAUDIO2_WIN8
-    IXAudio2SourceVoice_GetState(source, &state, XAUDIO2_VOICE_NOSAMPLESPLAYED);
-#else
-    IXAudio2SourceVoice_GetState(source, &state);
-#endif
-    while (state.BuffersQueued > 0) {
-        SDL_SemWait(this->hidden->semaphore);
-#if SDL_XAUDIO2_WIN8
-        IXAudio2SourceVoice_GetState(source, &state, XAUDIO2_VOICE_NOSAMPLESPLAYED);
-#else
-        IXAudio2SourceVoice_GetState(source, &state);
-#endif
+    if (source) {
+        IXAudio2SourceVoice_Discontinuity(source);
     }
 }
 
-
 static void
 XAUDIO2_CloseDevice(_THIS)
 {
@@ -489,7 +475,7 @@ XAUDIO2_Init(SDL_AudioDriverImpl * impl)
     impl->OpenDevice = XAUDIO2_OpenDevice;
     impl->PlayDevice = XAUDIO2_PlayDevice;
     impl->WaitDevice = XAUDIO2_WaitDevice;
-    impl->WaitDone = XAUDIO2_WaitDone;
+    impl->PrepareToClose = XAUDIO2_PrepareToClose;
     impl->GetDeviceBuf = XAUDIO2_GetDeviceBuf;
     impl->CloseDevice = XAUDIO2_CloseDevice;
     impl->Deinitialize = XAUDIO2_Deinitialize;