pandory500/SDL-mirror
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audio: Don't trust audio drivers to drain pending audio.

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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.
This commit is contained in:
Ryan C. Gordon 2016-10-07 15:13:46 -04:00
parent ae70bcd0f5
commit ff255ca66e
11 changed files with 19 additions and 130 deletions
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22
src/audio/SDL_audio.c
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@ -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.