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audio: Fix locking in backends that manage their own callback threads. 

Otherwise you might get a race where an app pauses the device, but
the audio callback still manages to run after the pause is in place.
This commit is contained in:
Ryan C. Gordon 2022-05-20 21:07:25 -04:00
parent a95f5a792c
commit dc62fec5e9
No known key found for this signature in database
GPG Key ID: FA148B892AB48044
6 changed files with 59 additions and 60 deletions
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12
src/audio/coreaudio/SDL_coreaudio.m
View File

@ -522,8 +522,12 @@ static void
outputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer)
{
SDL_AudioDevice *this = (SDL_AudioDevice *) inUserData;
SDL_LockMutex(this->mixer_lock);
if (SDL_AtomicGet(&this->hidden->shutdown)) {
return; /* don't do anything. */
SDL_UnlockMutex(this->mixer_lock);
return; /* don't do anything, since we don't even want to enqueue this buffer again. */
}
if (!SDL_AtomicGet(&this->enabled) || SDL_AtomicGet(&this->paused)) {
@ -536,10 +540,8 @@ outputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffe
while (remaining > 0) {
if (SDL_AudioStreamAvailable(this->stream) == 0) {
/* Generate the data */
SDL_LockMutex(this->mixer_lock);
(*this->callbackspec.callback)(this->callbackspec.userdata,
this->hidden->buffer, this->hidden->bufferSize);
SDL_UnlockMutex(this->mixer_lock);
this->hidden->bufferOffset = 0;
SDL_AudioStreamPut(this->stream, this->hidden->buffer, this->hidden->bufferSize);
}
@ -565,10 +567,8 @@ outputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffe
UInt32 len;
if (this->hidden->bufferOffset >= this->hidden->bufferSize) {
/* Generate the data */
SDL_LockMutex(this->mixer_lock);
(*this->callbackspec.callback)(this->callbackspec.userdata,
this->hidden->buffer, this->hidden->bufferSize);
SDL_UnlockMutex(this->mixer_lock);
this->hidden->bufferOffset = 0;
}
@ -587,6 +587,8 @@ outputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffe
AudioQueueEnqueueBuffer(this->hidden->audioQueue, inBuffer, 0, NULL);
inBuffer->mAudioDataByteSize = inBuffer->mAudioDataBytesCapacity;
SDL_UnlockMutex(this->mixer_lock);
}
static void

5
src/audio/emscripten/SDL_emscriptenaudio.c
View File

@ -28,6 +28,11 @@
#include <emscripten/emscripten.h>
/* !!! FIXME: this currently expects that the audio callback runs in the main thread,
!!! FIXME: in intervals when the application isn't running, but that may not be
!!! FIXME: true always once pthread support becomes widespread. Revisit this code
!!! FIXME: at some point and see what needs to be done for that! */
static void
FeedAudioDevice(_THIS, const void *buf, const int buflen)
{

45
src/audio/haiku/SDL_haikuaudio.cc
View File

@ -49,39 +49,40 @@ FillSound(void *device, void *stream, size_t len,
SDL_AudioDevice *audio = (SDL_AudioDevice *) device;
SDL_AudioCallback callback = audio->callbackspec.callback;
SDL_LockMutex(audio->mixer_lock);
/* Only do something if audio is enabled */
if (!SDL_AtomicGet(&audio->enabled) || SDL_AtomicGet(&audio->paused)) {
if (audio->stream) {
SDL_AudioStreamClear(audio->stream);
}
SDL_memset(stream, audio->spec.silence, len);
return;
}
} else {
SDL_assert(audio->spec.size == len);
SDL_assert(audio->spec.size == len);
if (audio->stream == NULL) { /* no conversion necessary. */
callback(audio->callbackspec.userdata, (Uint8 *) stream, len);
} else { /* streaming/converting */
const int stream_len = audio->callbackspec.size;
const int ilen = (int) len;
while (SDL_AudioStreamAvailable(audio->stream) < ilen) {
callback(audio->callbackspec.userdata, audio->work_buffer, stream_len);
if (SDL_AudioStreamPut(audio->stream, audio->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(audio->stream);
SDL_AtomicSet(&audio->enabled, 0);
break;
}
}
if (audio->stream == NULL) { /* no conversion necessary. */
SDL_LockMutex(audio->mixer_lock);
callback(audio->callbackspec.userdata, (Uint8 *) stream, len);
SDL_UnlockMutex(audio->mixer_lock);
} else { /* streaming/converting */
const int stream_len = audio->callbackspec.size;
const int ilen = (int) len;
while (SDL_AudioStreamAvailable(audio->stream) < ilen) {
callback(audio->callbackspec.userdata, audio->work_buffer, stream_len);
if (SDL_AudioStreamPut(audio->stream, audio->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(audio->stream);
SDL_AtomicSet(&audio->enabled, 0);
break;
const int got = SDL_AudioStreamGet(audio->stream, stream, ilen);
SDL_assert((got < 0) || (got == ilen));
if (got != ilen) {
SDL_memset(stream, audio->spec.silence, len);
}
}
const int got = SDL_AudioStreamGet(audio->stream, stream, ilen);
SDL_assert((got < 0) || (got == ilen));
if (got != ilen) {
SDL_memset(stream, audio->spec.silence, len);
}
}
SDL_UnlockMutex(audio->mixer_lock);
}
static void

45
src/audio/nacl/SDL_naclaudio.c
View File

@ -50,7 +50,7 @@ static void nacl_audio_callback(void* stream, uint32_t buffer_size, PP_TimeDelta
SDL_AudioDevice* _this = (SDL_AudioDevice*) data;
SDL_AudioCallback callback = _this->callbackspec.callback;
SDL_LockMutex(private->mutex); /* !!! FIXME: is this mutex necessary? */
SDL_LockMutex(_this->mixer_lock);
/* Only do something if audio is enabled */
if (!SDL_AtomicGet(&_this->enabled) || SDL_AtomicGet(&_this->paused)) {
@ -58,34 +58,31 @@ static void nacl_audio_callback(void* stream, uint32_t buffer_size, PP_TimeDelta
SDL_AudioStreamClear(_this->stream);
}
SDL_memset(stream, _this->spec.silence, len);
return;
}
} else {
SDL_assert(_this->spec.size == len);
SDL_assert(_this->spec.size == len);
if (_this->stream == NULL) { /* no conversion necessary. */
callback(_this->callbackspec.userdata, stream, len);
} else { /* streaming/converting */
const int stream_len = _this->callbackspec.size;
while (SDL_AudioStreamAvailable(_this->stream) < len) {
callback(_this->callbackspec.userdata, _this->work_buffer, stream_len);
if (SDL_AudioStreamPut(_this->stream, _this->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(_this->stream);
SDL_AtomicSet(&_this->enabled, 0);
break;
}
}
if (_this->stream == NULL) { /* no conversion necessary. */
SDL_LockMutex(_this->mixer_lock);
callback(_this->callbackspec.userdata, stream, len);
SDL_UnlockMutex(_this->mixer_lock);
} else { /* streaming/converting */
const int stream_len = _this->callbackspec.size;
while (SDL_AudioStreamAvailable(_this->stream) < len) {
callback(_this->callbackspec.userdata, _this->work_buffer, stream_len);
if (SDL_AudioStreamPut(_this->stream, _this->work_buffer, stream_len) == -1) {
SDL_AudioStreamClear(_this->stream);
SDL_AtomicSet(&_this->enabled, 0);
break;
const int got = SDL_AudioStreamGet(_this->stream, stream, len);
SDL_assert((got < 0) || (got == len));
if (got != len) {
SDL_memset(stream, _this->spec.silence, len);
}
}
const int got = SDL_AudioStreamGet(_this->stream, stream, len);
SDL_assert((got < 0) || (got == len));
if (got != len) {
SDL_memset(stream, _this->spec.silence, len);
}
}
SDL_UnlockMutex(private->mutex);
SDL_UnlockMutex(_this->mixer_lock);
}
static void NACLAUDIO_CloseDevice(SDL_AudioDevice *device) {
@ -94,7 +91,6 @@ static void NACLAUDIO_CloseDevice(SDL_AudioDevice *device) {
SDL_PrivateAudioData *hidden = (SDL_PrivateAudioData *) device->hidden;
ppb_audio->StopPlayback(hidden->audio);
SDL_DestroyMutex(hidden->mutex);
core->ReleaseResource(hidden->audio);
}
@ -109,7 +105,6 @@ NACLAUDIO_OpenDevice(_THIS, const char *devname) {
return SDL_OutOfMemory();
}
private->mutex = SDL_CreateMutex();
_this->spec.freq = 44100;
_this->spec.format = AUDIO_S16LSB;
_this->spec.channels = 2;

3
src/audio/nacl/SDL_naclaudio.h
View File

@ -34,8 +34,7 @@
#define private _this->hidden
typedef struct SDL_PrivateAudioData {
SDL_mutex* mutex;
PP_Resource audio;
PP_Resource audio;
} SDL_PrivateAudioData;
#endif /* SDL_naclaudio_h_ */

7
src/audio/pipewire/SDL_pipewire.c
View File

@ -910,6 +910,7 @@ output_callback(void *data)
* and run the callback with the work buffer to keep the callback
* firing regularly in case the audio is being used as a timer.
*/
SDL_LockMutex(this->mixer_lock);
if (!SDL_AtomicGet(&this->paused)) {
if (SDL_AtomicGet(&this->enabled)) {
dst = spa_buf->datas[0].data;
@ -919,18 +920,13 @@ output_callback(void *data)
}
if (!this->stream) {
SDL_LockMutex(this->mixer_lock);
this->callbackspec.callback(this->callbackspec.userdata, dst, this->callbackspec.size);
SDL_UnlockMutex(this->mixer_lock);
} else {
int got;
/* Fire the callback until we have enough to fill a buffer */
while (SDL_AudioStreamAvailable(this->stream) < this->spec.size) {
SDL_LockMutex(this->mixer_lock);
this->callbackspec.callback(this->callbackspec.userdata, this->work_buffer, this->callbackspec.size);
SDL_UnlockMutex(this->mixer_lock);
SDL_AudioStreamPut(this->stream, this->work_buffer, this->callbackspec.size);
}
@ -940,6 +936,7 @@ output_callback(void *data)
} else {
SDL_memset(spa_buf->datas[0].data, this->spec.silence, this->spec.size);
}
SDL_UnlockMutex(this->mixer_lock);
spa_buf->datas[0].chunk->offset = 0;
spa_buf->datas[0].chunk->stride = this->hidden->stride;