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Commit 2034ba88 authored by David Fuhrmann's avatar David Fuhrmann
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auhal: rework locking and avoid potential deadlock 

hopefully closes #11675
parent a9863cf8
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Showing with 47 additions and 25 deletions
modules/audio_output/auhal.c
View file @ 2034ba88
......@@ -106,8 +106,12 @@ struct aout_sys_t
int i_bytes_per_sample;
CFArrayRef device_list;
vlc_mutex_t device_list_lock; /* protects access to device_list */
vlc_mutex_t var_lock; /* protects access to device_list and i_selected_dev */
vlc_mutex_t selected_device_lock;/* Synchronizes access to i_selected_dev. This is only needed
between VLCs audio thread and the core audio callback thread.
The value is only changed in Start, further access to this variable
within the audio thread (start, stop, close) needs no protection. */
float f_volume;
bool b_mute;
......@@ -186,7 +190,8 @@ static int Open(vlc_object_t *obj)
OSStatus err = noErr;
vlc_mutex_init(&p_sys->var_lock);
vlc_mutex_init(&p_sys->device_list_lock);
vlc_mutex_init(&p_sys->selected_device_lock);
vlc_mutex_init(&p_sys->lock);
vlc_cond_init(&p_sys->cond);
p_sys->b_digital = false;
......@@ -263,13 +268,21 @@ static void Close(vlc_object_t *obj)
if (err != noErr)
msg_Err(p_aout, "failed to remove listener for default audio device [%4.4s]", (char *)&err);
vlc_mutex_lock(&p_sys->var_lock);
/*
* StreamsChangedListener can rebuild the device list and thus held the device_list_lock.
* To avoid a possible deadlock, an array copy is created here.
* In rare cases, this can lead to missing StreamsChangedListener callback deregistration (TODO).
*/
vlc_mutex_lock(&p_sys->device_list_lock);
CFArrayRef device_list_cpy = CFArrayCreateCopy(NULL, p_sys->device_list);
vlc_mutex_unlock(&p_sys->device_list_lock);
/* remove streams callbacks */
CFIndex count = CFArrayGetCount(p_sys->device_list);
CFIndex count = CFArrayGetCount(device_list_cpy);
if (count > 0) {
for (CFIndex x = 0; x < count; x++) {
AudioDeviceID deviceId = 0;
CFNumberRef cfn_device_id = CFArrayGetValueAtIndex(p_sys->device_list, x);
CFNumberRef cfn_device_id = CFArrayGetValueAtIndex(device_list_cpy, x);
if (!cfn_device_id)
continue;
......@@ -280,14 +293,15 @@ static void Close(vlc_object_t *obj)
}
}
CFRelease(device_list_cpy);
CFRelease(p_sys->device_list);
vlc_mutex_unlock(&p_sys->var_lock);
char *psz_device = aout_DeviceGet(p_aout);
config_PutPsz(p_aout, "auhal-audio-device", psz_device);
free(psz_device);
vlc_mutex_destroy(&p_sys->var_lock);
vlc_mutex_destroy(&p_sys->selected_device_lock);
vlc_mutex_destroy(&p_sys->device_list_lock);
vlc_mutex_destroy(&p_sys->lock);
vlc_cond_destroy(&p_sys->cond);
......@@ -318,7 +332,7 @@ static int Start(audio_output_t *p_aout, audio_sample_format_t *restrict fmt)
p_sys->b_paused = false;
p_sys->i_device_latency = 0;
vlc_mutex_lock(&p_sys->var_lock);
vlc_mutex_lock(&p_sys->selected_device_lock);
p_sys->i_selected_dev = p_sys->i_new_selected_dev;
aout_FormatPrint(p_aout, "VLC is looking for:", fmt);
......@@ -365,7 +379,7 @@ static int Start(audio_output_t *p_aout, audio_sample_format_t *restrict fmt)
err = AudioObjectGetPropertyData(kAudioObjectSystemObject, &defaultDeviceAddress, 0, NULL, &propertySize, &defaultDeviceID);
if (err != noErr) {
msg_Err(p_aout, "could not get default audio device [%4.4s]", (char *)&err);
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
goto error;
}
else
......@@ -374,7 +388,7 @@ static int Start(audio_output_t *p_aout, audio_sample_format_t *restrict fmt)
p_sys->i_selected_dev = defaultDeviceID;
p_sys->b_selected_dev_is_digital = var_InheritBool(p_aout, "spdif");
}
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
// recheck if device still supports digital
b_start_digital = p_sys->b_selected_dev_is_digital;
......@@ -1286,7 +1300,7 @@ static void RebuildDeviceList(audio_output_t * p_aout)
free(psz_name);
}
vlc_mutex_lock(&p_sys->var_lock);
vlc_mutex_lock(&p_sys->device_list_lock);
CFIndex count = 0;
if (p_sys->device_list)
count = CFArrayGetCount(p_sys->device_list);
......@@ -1302,6 +1316,7 @@ static void RebuildDeviceList(audio_output_t * p_aout)
if (cfn_device_id) {
CFNumberGetValue(cfn_device_id, kCFNumberSInt32Type, &i_device_id);
msg_Dbg(p_aout, "Device ID %i is not found in new array, deleting.", i_device_id);
ReportDevice(p_aout, i_device_id, NULL);
}
}
......@@ -1311,7 +1326,7 @@ static void RebuildDeviceList(audio_output_t * p_aout)
CFRelease(p_sys->device_list);
p_sys->device_list = CFArrayCreateCopy(kCFAllocatorDefault, currentListOfDevices);
CFRelease(currentListOfDevices);
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->device_list_lock);
free(deviceIDs);
}
......@@ -1582,12 +1597,14 @@ static OSStatus DevicesListener(AudioObjectID inObjectID, UInt32 inNumberAddres
msg_Dbg(p_aout, "audio device configuration changed, resetting cache");
RebuildDeviceList(p_aout);
vlc_mutex_lock(&p_sys->var_lock);
vlc_mutex_lock(&p_sys->selected_device_lock);
vlc_mutex_lock(&p_sys->device_list_lock);
CFNumberRef selectedDevice = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &p_sys->i_selected_dev);
if(!CFArrayContainsValue(p_sys->device_list, CFRangeMake(0, CFArrayGetCount(p_sys->device_list)), selectedDevice))
aout_RestartRequest(p_aout, AOUT_RESTART_OUTPUT);
CFRelease(selectedDevice);
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->device_list_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
return noErr;
}
......@@ -1624,6 +1641,8 @@ static OSStatus DefaultDeviceChangedListener(AudioObjectID inObjectID, UInt32 i
if (!p_aout)
return -1;
aout_sys_t *p_sys = p_aout->sys;
if (!p_aout->sys->b_selected_dev_is_default)
return noErr;
......@@ -1646,12 +1665,13 @@ static OSStatus DefaultDeviceChangedListener(AudioObjectID inObjectID, UInt32 i
return noErr;
}
vlc_mutex_lock(&p_sys->selected_device_lock);
/* Also ignore events which announce the same device id */
if(defaultDeviceID == p_aout->sys->i_selected_dev)
return noErr;
msg_Dbg(p_aout, "default device actually changed, resetting aout");
aout_RestartRequest(p_aout, AOUT_RESTART_OUTPUT);
if(defaultDeviceID != p_aout->sys->i_selected_dev) {
msg_Dbg(p_aout, "default device actually changed, resetting aout");
aout_RestartRequest(p_aout, AOUT_RESTART_OUTPUT);
}
vlc_mutex_unlock(&p_sys->selected_device_lock);
return noErr;
}
......@@ -1680,37 +1700,39 @@ static OSStatus StreamsChangedListener(AudioObjectID inObjectID, UInt32 inNumbe
msg_Dbg(p_aout, "available physical formats for audio device changed");
RebuildDeviceList(p_aout);
vlc_mutex_lock(&p_sys->selected_device_lock);
/* In this case audio has not yet started. Below code will not work and is not needed here. */
if (p_sys->i_selected_dev == 0)
if (p_sys->i_selected_dev == 0) {
vlc_mutex_unlock(&p_sys->selected_device_lock);
return 0;
}
/*
* check if changed stream id belongs to current device
*/
vlc_mutex_lock(&p_sys->var_lock);
AudioObjectPropertyAddress streamsAddress = { kAudioDevicePropertyStreams, kAudioDevicePropertyScopeOutput, kAudioObjectPropertyElementMaster };
err = AudioObjectGetPropertyDataSize(p_sys->i_selected_dev, &streamsAddress, 0, NULL, &i_param_size);
if (err != noErr) {
msg_Err(p_aout, "could not get number of streams for device %i [%4.4s]", p_sys->i_selected_dev, (char *)&err);
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
return VLC_EGENERIC;
}
i_streams = i_param_size / sizeof(AudioStreamID);
p_streams = (AudioStreamID *)malloc(i_param_size);
if (p_streams == NULL) {
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
return VLC_ENOMEM;
}
err = AudioObjectGetPropertyData(p_sys->i_selected_dev, &streamsAddress, 0, NULL, &i_param_size, p_streams);
if (err != noErr) {
msg_Err(p_aout, "could not get list of streams [%4.4s]", (char *)&err);
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
free(p_streams);
return VLC_EGENERIC;
}
vlc_mutex_unlock(&p_sys->var_lock);
vlc_mutex_unlock(&p_sys->selected_device_lock);
for (int i = 0; i < i_streams; i++) {
if (p_streams[i] == inObjectID) {
......
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