Make the Connected state atomic

Also don't send the Disconnected event more than once.

16 files changed, 82 insertions, 79 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index 3c9598ca..915addac 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -3248,7 +3248,7 @@ static ALCsizei GetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALC
                 values[i++] = ALC_CAPTURE_SAMPLES;
                 values[i++] = V0(device->Backend,availableSamples)();
                 values[i++] = ALC_CONNECTED;
-                values[i++] = device->Connected;
+                values[i++] = ATOMIC_LOAD(&device->Connected, almemory_order_relaxed);
                 almtx_unlock(&device->BackendLock);
 
                 values[i++] = 0;
@@ -3268,7 +3268,7 @@ static ALCsizei GetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALC
                 return 1;
 
             case ALC_CONNECTED:
-                values[0] = device->Connected;
+                values[0] = ATOMIC_LOAD(&device->Connected, almemory_order_acquire);
                 return 1;
 
             default:
@@ -3457,7 +3457,7 @@ static ALCsizei GetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALC
             return 1;
 
         case ALC_CONNECTED:
-            values[0] = device->Connected;
+            values[0] = ATOMIC_LOAD(&device->Connected, almemory_order_acquire);
             return 1;
 
         case ALC_HRTF_SOFT:
@@ -3764,7 +3764,8 @@ ALC_API ALCcontext* ALC_APIENTRY alcCreateContext(ALCdevice *device, const ALCin
      * properly cleaned up after being made.
      */
     LockLists();
-    if(!VerifyDevice(&device) || device->Type == Capture || !device->Connected)
+    if(!VerifyDevice(&device) || device->Type == Capture ||
+       !ATOMIC_LOAD(&device->Connected, almemory_order_relaxed))
     {
         UnlockLists();
         alcSetError(device, ALC_INVALID_DEVICE);
@@ -4034,7 +4035,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
 
     //Validate device
     InitRef(&device->ref, 1);
-    device->Connected = ALC_TRUE;
+    ATOMIC_INIT(&device->Connected, ALC_TRUE);
     device->Type = Playback;
     ATOMIC_INIT(&device->LastError, ALC_NO_ERROR);
 
@@ -4290,7 +4291,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcCaptureOpenDevice(const ALCchar *deviceName,
 
     //Validate device
     InitRef(&device->ref, 1);
-    device->Connected = ALC_TRUE;
+    ATOMIC_INIT(&device->Connected, ALC_TRUE);
     device->Type = Capture;
 
     InitDevice(device);
@@ -4389,7 +4390,7 @@ ALC_API void ALC_APIENTRY alcCaptureStart(ALCdevice *device)
     else
     {
         almtx_lock(&device->BackendLock);
-        if(!device->Connected)
+        if(!ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
             alcSetError(device, ALC_INVALID_DEVICE);
         else if(!(device->Flags&DEVICE_RUNNING))
         {
@@ -4474,7 +4475,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceN
 
     //Validate device
     InitRef(&device->ref, 1);
-    device->Connected = ALC_TRUE;
+    ATOMIC_INIT(&device->Connected, ALC_TRUE);
     device->Type = Loopback;
     ATOMIC_INIT(&device->LastError, ALC_NO_ERROR);
 
@@ -4675,7 +4676,8 @@ ALC_API ALCboolean ALC_APIENTRY alcResetDeviceSOFT(ALCdevice *device, const ALCi
     ALCenum err;
 
     LockLists();
-    if(!VerifyDevice(&device) || device->Type == Capture || !device->Connected)
+    if(!VerifyDevice(&device) || device->Type == Capture ||
+       !ATOMIC_LOAD(&device->Connected, almemory_order_relaxed))
     {
         UnlockLists();
         alcSetError(device, ALC_INVALID_DEVICE);
diff --git a/Alc/ALu.c b/Alc/ALu.c
index 9f4f7a30..2435558d 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -1857,7 +1857,8 @@ void aluHandleDisconnect(ALCdevice *device, const char *msg, ...)
     va_list args;
     int msglen;
 
-    device->Connected = ALC_FALSE;
+    if(!ATOMIC_EXCHANGE(&device->Connected, AL_FALSE, almemory_order_acq_rel))
+        return;
 
     evt.EnumType = EventType_Disconnected;
     evt.Type = AL_EVENT_TYPE_DISCONNECTED_SOFT;
diff --git a/Alc/backends/alsa.c b/Alc/backends/alsa.c
index 72e2936f..c75749de 100644
--- a/Alc/backends/alsa.c
+++ b/Alc/backends/alsa.c
@@ -438,7 +438,7 @@ typedef struct ALCplaybackAlsa {
     ALvoid *buffer;
     ALsizei size;
 
-    volatile int killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCplaybackAlsa;
 
@@ -468,6 +468,8 @@ static void ALCplaybackAlsa_Construct(ALCplaybackAlsa *self, ALCdevice *device)
 
     self->pcmHandle = NULL;
     self->buffer = NULL;
+
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 void ALCplaybackAlsa_Destruct(ALCplaybackAlsa *self)
@@ -495,7 +497,7 @@ static int ALCplaybackAlsa_mixerProc(void *ptr)
 
     update_size = device->UpdateSize;
     num_updates = device->NumUpdates;
-    while(!self->killNow)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire))
     {
         int state = verify_state(self->pcmHandle);
         if(state < 0)
@@ -585,7 +587,7 @@ static int ALCplaybackAlsa_mixerNoMMapProc(void *ptr)
 
     update_size = device->UpdateSize;
     num_updates = device->NumUpdates;
-    while(!self->killNow)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire))
     {
         int state = verify_state(self->pcmHandle);
         if(state < 0)
@@ -910,7 +912,7 @@ static ALCboolean ALCplaybackAlsa_start(ALCplaybackAlsa *self)
         }
         thread_func = ALCplaybackAlsa_mixerProc;
     }
-    self->killNow = 0;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, thread_func, self) != althrd_success)
     {
         ERR("Could not create playback thread\n");
@@ -931,10 +933,8 @@ static void ALCplaybackAlsa_stop(ALCplaybackAlsa *self)
 {
     int res;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    self->killNow = 1;
     althrd_join(self->thread, &res);
 
     al_free(self->buffer);
@@ -1207,7 +1207,7 @@ static ALCenum ALCcaptureAlsa_captureSamples(ALCcaptureAlsa *self, ALCvoid *buff
     }
 
     self->last_avail -= samples;
-    while(device->Connected && samples > 0)
+    while(ATOMIC_LOAD(&device->Connected, almemory_order_acquire) && samples > 0)
     {
         snd_pcm_sframes_t amt = 0;
 
@@ -1275,7 +1275,7 @@ static ALCuint ALCcaptureAlsa_availableSamples(ALCcaptureAlsa *self)
     ALCdevice *device = STATIC_CAST(ALCbackend, self)->mDevice;
     snd_pcm_sframes_t avail = 0;
 
-    if(device->Connected && self->doCapture)
+    if(ATOMIC_LOAD(&device->Connected, almemory_order_acquire) && self->doCapture)
         avail = snd_pcm_avail_update(self->pcmHandle);
     if(avail < 0)
     {
diff --git a/Alc/backends/dsound.c b/Alc/backends/dsound.c
index bca8b7f0..0040a840 100644
--- a/Alc/backends/dsound.c
+++ b/Alc/backends/dsound.c
@@ -185,7 +185,7 @@ typedef struct ALCdsoundPlayback {
     IDirectSoundNotify *Notifies;
     HANDLE             NotifyEvent;
 
-    volatile int killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCdsoundPlayback;
 
@@ -217,6 +217,7 @@ static void ALCdsoundPlayback_Construct(ALCdsoundPlayback *self, ALCdevice *devi
     self->Buffer = NULL;
     self->Notifies = NULL;
     self->NotifyEvent = NULL;
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCdsoundPlayback_Destruct(ALCdsoundPlayback *self)
@@ -276,7 +277,8 @@ FORCE_ALIGN static int ALCdsoundPlayback_mixerProc(void *ptr)
     FragSize = device->UpdateSize * FrameSize;
 
     IDirectSoundBuffer_GetCurrentPosition(self->Buffer, &LastCursor, NULL);
-    while(!self->killNow)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         // Get current play cursor
         IDirectSoundBuffer_GetCurrentPosition(self->Buffer, &PlayCursor, NULL);
@@ -636,7 +638,7 @@ retry_open:
 
 static ALCboolean ALCdsoundPlayback_start(ALCdsoundPlayback *self)
 {
-    self->killNow = 0;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCdsoundPlayback_mixerProc, self) != althrd_success)
         return ALC_FALSE;
 
@@ -647,10 +649,8 @@ static void ALCdsoundPlayback_stop(ALCdsoundPlayback *self)
 {
     int res;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    self->killNow = 1;
     althrd_join(self->thread, &res);
 
     IDirectSoundBuffer_Stop(self->Buffer);
@@ -930,7 +930,7 @@ static ALCuint ALCdsoundCapture_availableSamples(ALCdsoundCapture *self)
     DWORD FrameSize;
     HRESULT hr;
 
-    if(!device->Connected)
+    if(!ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
         goto done;
 
     FrameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
diff --git a/Alc/backends/jack.c b/Alc/backends/jack.c
index 2f17bbf6..e6f4b435 100644
--- a/Alc/backends/jack.c
+++ b/Alc/backends/jack.c
@@ -312,7 +312,8 @@ static int ALCjackPlayback_mixerProc(void *arg)
     althrd_setname(althrd_current(), MIXER_THREAD_NAME);
 
     ALCjackPlayback_lock(self);
-    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         ALuint todo, len1, len2;
 
diff --git a/Alc/backends/null.c b/Alc/backends/null.c
index d17c8bda..2c2db54e 100644
--- a/Alc/backends/null.c
+++ b/Alc/backends/null.c
@@ -36,7 +36,7 @@
 typedef struct ALCnullBackend {
     DERIVE_FROM_TYPE(ALCbackend);
 
-    volatile int killNow;
+    ATOMIC(int) killNow;
     althrd_t thread;
 } ALCnullBackend;
 
@@ -65,6 +65,8 @@ static void ALCnullBackend_Construct(ALCnullBackend *self, ALCdevice *device)
 {
     ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
     SET_VTABLE2(ALCnullBackend, ALCbackend, self);
+
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 
@@ -86,7 +88,8 @@ static int ALCnullBackend_mixerProc(void *ptr)
         ERR("Failed to get starting time\n");
         return 1;
     }
-    while(!self->killNow && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         if(altimespec_get(&now, AL_TIME_UTC) != AL_TIME_UTC)
         {
@@ -142,7 +145,7 @@ static ALCboolean ALCnullBackend_reset(ALCnullBackend *self)
 
 static ALCboolean ALCnullBackend_start(ALCnullBackend *self)
 {
-    self->killNow = 0;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCnullBackend_mixerProc, self) != althrd_success)
         return ALC_FALSE;
     return ALC_TRUE;
@@ -152,10 +155,8 @@ static void ALCnullBackend_stop(ALCnullBackend *self)
 {
     int res;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    self->killNow = 1;
     althrd_join(self->thread, &res);
 }
 
diff --git a/Alc/backends/opensl.c b/Alc/backends/opensl.c
index 93d2e521..b20d7841 100644
--- a/Alc/backends/opensl.c
+++ b/Alc/backends/opensl.c
@@ -266,7 +266,8 @@ static int ALCopenslPlayback_mixerProc(void *arg)
     padding = ll_ringbuffer_write_space(self->mRing) - device->NumUpdates;
 
     ALCopenslPlayback_lock(self);
-    while(ATOMIC_LOAD_SEQ(&self->mKillNow) == AL_FALSE && device->Connected)
+    while(!ATOMIC_LOAD(&self->mKillNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         size_t todo, len0, len1;
 
diff --git a/Alc/backends/oss.c b/Alc/backends/oss.c
index 9b0c2d42..faf3ee99 100644
--- a/Alc/backends/oss.c
+++ b/Alc/backends/oss.c
@@ -284,7 +284,8 @@ static int ALCplaybackOSS_mixerProc(void *ptr)
     frame_size = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
 
     ALCplaybackOSS_lock(self);
-    while(!ATOMIC_LOAD_SEQ(&self->killNow) && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         FD_ZERO(&wfds);
         FD_SET(self->fd, &wfds);
diff --git a/Alc/backends/pulseaudio.c b/Alc/backends/pulseaudio.c
index 6ba82cd2..96794e20 100644
--- a/Alc/backends/pulseaudio.c
+++ b/Alc/backends/pulseaudio.c
@@ -472,7 +472,7 @@ typedef struct ALCpulsePlayback {
     pa_stream *stream;
     pa_context *context;
 
-    volatile ALboolean killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCpulsePlayback;
 
@@ -515,6 +515,7 @@ static void ALCpulsePlayback_Construct(ALCpulsePlayback *self, ALCdevice *device
 
     self->loop = NULL;
     AL_STRING_INIT(self->device_name);
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCpulsePlayback_Destruct(ALCpulsePlayback *self)
@@ -829,7 +830,8 @@ static int ALCpulsePlayback_mixerProc(void *ptr)
     pa_threaded_mainloop_lock(self->loop);
     frame_size = pa_frame_size(&self->spec);
 
-    while(!self->killNow && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         len = pa_stream_writable_size(self->stream);
         if(len < 0)
@@ -1141,7 +1143,7 @@ static ALCboolean ALCpulsePlayback_reset(ALCpulsePlayback *self)
 
 static ALCboolean ALCpulsePlayback_start(ALCpulsePlayback *self)
 {
-    self->killNow = AL_FALSE;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCpulsePlayback_mixerProc, self) != althrd_success)
         return ALC_FALSE;
     return ALC_TRUE;
@@ -1152,10 +1154,9 @@ static void ALCpulsePlayback_stop(ALCpulsePlayback *self)
     pa_operation *o;
     int res;
 
-    if(!self->stream || self->killNow)
+    if(!self->stream || ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
 
-    self->killNow = AL_TRUE;
     /* Signal the main loop in case PulseAudio isn't sending us audio requests
      * (e.g. if the device is suspended). We need to lock the mainloop in case
      * the mixer is between checking the killNow flag but before waiting for
@@ -1705,7 +1706,7 @@ static ALCuint ALCpulseCapture_availableSamples(ALCpulseCapture *self)
     ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
     size_t readable = self->cap_remain;
 
-    if(device->Connected)
+    if(ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         ssize_t got;
         pa_threaded_mainloop_lock(self->loop);
diff --git a/Alc/backends/qsa.c b/Alc/backends/qsa.c
index 484cadaa..8f87779b 100644
--- a/Alc/backends/qsa.c
+++ b/Alc/backends/qsa.c
@@ -46,7 +46,7 @@ typedef struct {
     ALvoid* buffer;
     ALsizei size;
 
-    volatile int killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } qsa_data;
 
@@ -206,7 +206,7 @@ FORCE_ALIGN static int qsa_proc_playback(void *ptr)
     );
 
     V0(device->Backend,lock)();
-    while(!data->killNow)
+    while(!ATOMIC_LOAD(&data->killNow, almemory_order_acquire))
     {
         FD_ZERO(&wfds);
         FD_SET(data->audio_fd, &wfds);
@@ -232,7 +232,7 @@ FORCE_ALIGN static int qsa_proc_playback(void *ptr)
         len = data->size;
         write_ptr = data->buffer;
         aluMixData(device, write_ptr, len/frame_size);
-        while(len>0 && !data->killNow)
+        while(len>0 && !ATOMIC_LOAD(&data->killNow, almemory_order_acquire))
         {
             int wrote = snd_pcm_plugin_write(data->pcmHandle, write_ptr, len);
             if(wrote <= 0)
@@ -282,6 +282,7 @@ static ALCenum qsa_open_playback(PlaybackWrapper *self, const ALCchar* deviceNam
     data = (qsa_data*)calloc(1, sizeof(qsa_data));
     if(data == NULL)
         return ALC_OUT_OF_MEMORY;
+    ATOMIC_INIT(&data->killNow, AL_TRUE);
 
     if(!deviceName)
         deviceName = qsaDevice;
@@ -595,7 +596,7 @@ static ALCboolean qsa_start_playback(PlaybackWrapper *self)
 {
     qsa_data *data = self->ExtraData;
 
-    data->killNow = 0;
+    ATOMIC_STORE(&data->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&data->thread, qsa_proc_playback, self) != althrd_success)
         return ALC_FALSE;
 
@@ -607,10 +608,8 @@ static void qsa_stop_playback(PlaybackWrapper *self)
     qsa_data *data = self->ExtraData;
     int res;
 
-    if(data->killNow)
+    if(ATOMIC_EXCHANGE(&data->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    data->killNow = 1;
     althrd_join(data->thread, &res);
 }
 
diff --git a/Alc/backends/sndio.c b/Alc/backends/sndio.c
index 06a434d9..5aea457b 100644
--- a/Alc/backends/sndio.c
+++ b/Alc/backends/sndio.c
@@ -43,7 +43,7 @@ typedef struct ALCsndioBackend {
     ALvoid *mix_data;
     ALsizei data_size;
 
-    volatile int killNow;
+    ATOMIC(int) killNow;
     althrd_t thread;
 } ALCsndioBackend;
 
@@ -75,6 +75,7 @@ static void ALCsndioBackend_Construct(ALCsndioBackend *self, ALCdevice *device)
 
     self->sndHandle = NULL;
     self->mix_data = NULL;
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCsndioBackend_Destruct(ALCsndioBackend *self)
@@ -102,7 +103,8 @@ static int ALCsndioBackend_mixerProc(void *ptr)
 
     frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
 
-    while(!self->killNow && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         ALsizei len = self->data_size;
         ALubyte *WritePtr = self->mix_data;
@@ -110,7 +112,7 @@ static int ALCsndioBackend_mixerProc(void *ptr)
         ALCsndioBackend_lock(self);
         aluMixData(device, WritePtr, len/frameSize);
         ALCsndioBackend_unlock(self);
-        while(len > 0 && !self->killNow)
+        while(len > 0 && !ATOMIC_LOAD(&self->killNow, almemory_order_acquire))
         {
             wrote = sio_write(self->sndHandle, WritePtr, len);
             if(wrote == 0)
@@ -253,7 +255,7 @@ static ALCboolean ALCsndioBackend_start(ALCsndioBackend *self)
         return ALC_FALSE;
     }
 
-    self->killNow = 0;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCsndioBackend_mixerProc, self) != althrd_success)
     {
         sio_stop(self->sndHandle);
@@ -267,10 +269,8 @@ static void ALCsndioBackend_stop(ALCsndioBackend *self)
 {
     int res;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    self->killNow = 1;
     althrd_join(self->thread, &res);
 
     if(!sio_stop(self->sndHandle))
diff --git a/Alc/backends/solaris.c b/Alc/backends/solaris.c
index fdc62562..f1c4aeaa 100644
--- a/Alc/backends/solaris.c
+++ b/Alc/backends/solaris.c
@@ -120,7 +120,8 @@ static int ALCsolarisBackend_mixerProc(void *ptr)
     frame_size = FrameSizeFromDevFmt(device->FmtChans, device->FmtType, device->AmbiOrder);
 
     ALCsolarisBackend_lock(self);
-    while(!ATOMIC_LOAD_SEQ(&self->killNow) && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         FD_ZERO(&wfds);
         FD_SET(self->fd, &wfds);
diff --git a/Alc/backends/wave.c b/Alc/backends/wave.c
index 13ffaeec..557c2bf2 100644
--- a/Alc/backends/wave.c
+++ b/Alc/backends/wave.c
@@ -77,7 +77,7 @@ typedef struct ALCwaveBackend {
     ALvoid *mBuffer;
     ALuint mSize;
 
-    volatile int killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCwaveBackend;
 
@@ -110,7 +110,7 @@ static void ALCwaveBackend_Construct(ALCwaveBackend *self, ALCdevice *device)
     self->mBuffer = NULL;
     self->mSize = 0;
 
-    self->killNow = 1;
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCwaveBackend_Destruct(ALCwaveBackend *self)
@@ -143,7 +143,8 @@ static int ALCwaveBackend_mixerProc(void *ptr)
         ERR("Failed to get starting time\n");
         return 1;
     }
-    while(!self->killNow && device->Connected)
+    while(!ATOMIC_LOAD(&self->killNow, almemory_order_acquire) &&
+          ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         if(altimespec_get(&now, AL_TIME_UTC) != AL_TIME_UTC)
         {
@@ -355,7 +356,7 @@ static ALCboolean ALCwaveBackend_start(ALCwaveBackend *self)
         return ALC_FALSE;
     }
 
-    self->killNow = 0;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCwaveBackend_mixerProc, self) != althrd_success)
     {
         free(self->mBuffer);
@@ -373,10 +374,8 @@ static void ALCwaveBackend_stop(ALCwaveBackend *self)
     long size;
     int res;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    self->killNow = 1;
     althrd_join(self->thread, &res);
 
     free(self->mBuffer);
diff --git a/Alc/backends/winmm.c b/Alc/backends/winmm.c
index 59164441..d6ecd7a9 100644
--- a/Alc/backends/winmm.c
+++ b/Alc/backends/winmm.c
@@ -148,7 +148,7 @@ typedef struct ALCwinmmPlayback {
 
     WAVEFORMATEX Format;
 
-    volatile ALboolean killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCwinmmPlayback;
 
@@ -180,7 +180,7 @@ static void ALCwinmmPlayback_Construct(ALCwinmmPlayback *self, ALCdevice *device
     InitRef(&self->WaveBuffersCommitted, 0);
     self->OutHdl = NULL;
 
-    self->killNow = AL_TRUE;
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCwinmmPlayback_Destruct(ALCwinmmPlayback *self)
@@ -224,7 +224,7 @@ FORCE_ALIGN static int ALCwinmmPlayback_mixerProc(void *arg)
         if(msg.message != WOM_DONE)
             continue;
 
-        if(self->killNow)
+        if(ATOMIC_LOAD(&self->killNow, almemory_order_acquire))
         {
             if(ReadRef(&self->WaveBuffersCommitted) == 0)
                 break;
@@ -371,7 +371,7 @@ static ALCboolean ALCwinmmPlayback_start(ALCwinmmPlayback *self)
     ALint BufferSize;
     ALuint i;
 
-    self->killNow = AL_FALSE;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCwinmmPlayback_mixerProc, self) != althrd_success)
         return ALC_FALSE;
 
@@ -402,11 +402,8 @@ static void ALCwinmmPlayback_stop(ALCwinmmPlayback *self)
     void *buffer = NULL;
     int i;
 
-    if(self->killNow)
+    if(ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
         return;
-
-    // Set flag to stop processing headers
-    self->killNow = AL_TRUE;
     althrd_join(self->thread, &i);
 
     // Release the wave buffers
@@ -433,7 +430,7 @@ typedef struct ALCwinmmCapture {
 
     WAVEFORMATEX Format;
 
-    volatile ALboolean killNow;
+    ATOMIC(ALenum) killNow;
     althrd_t thread;
 } ALCwinmmCapture;
 
@@ -465,7 +462,7 @@ static void ALCwinmmCapture_Construct(ALCwinmmCapture *self, ALCdevice *device)
     InitRef(&self->WaveBuffersCommitted, 0);
     self->InHdl = NULL;
 
-    self->killNow = AL_TRUE;
+    ATOMIC_INIT(&self->killNow, AL_TRUE);
 }
 
 static void ALCwinmmCapture_Destruct(ALCwinmmCapture *self)
@@ -474,9 +471,8 @@ static void ALCwinmmCapture_Destruct(ALCwinmmCapture *self)
     int i;
 
     /* Tell the processing thread to quit and wait for it to do so. */
-    if(!self->killNow)
+    if(!ATOMIC_EXCHANGE(&self->killNow, AL_TRUE, almemory_order_acq_rel))
     {
-        self->killNow = AL_TRUE;
         PostThreadMessage(self->thread, WM_QUIT, 0, 0);
 
         althrd_join(self->thread, &i);
@@ -536,7 +532,7 @@ static int ALCwinmmCapture_captureProc(void *arg)
             continue;
         /* Don't wait for other buffers to finish before quitting. We're
          * closing so we don't need them. */
-        if(self->killNow)
+        if(ATOMIC_LOAD(&self->killNow, almemory_order_acquire))
             break;
 
         WaveHdr = ((WAVEHDR*)msg.lParam);
@@ -656,7 +652,7 @@ static ALCenum ALCwinmmCapture_open(ALCwinmmCapture *self, const ALCchar *name)
         IncrementRef(&self->WaveBuffersCommitted);
     }
 
-    self->killNow = AL_FALSE;
+    ATOMIC_STORE(&self->killNow, AL_FALSE, almemory_order_release);
     if(althrd_create(&self->thread, ALCwinmmCapture_captureProc, self) != althrd_success)
         goto failure;
 
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index 5c2435a4..baf610b8 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -466,7 +466,7 @@ struct ALCdevice_struct
 {
     RefCount ref;
 
-    ALCboolean Connected;
+    ATOMIC(ALenum) Connected;
     enum DeviceType Type;
 
     ALuint Frequency;
diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index c20226ca..8c8b2149 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -2518,7 +2518,7 @@ AL_API ALvoid AL_APIENTRY alSourcePlayv(ALsizei n, const ALuint *sources)
     device = context->Device;
     ALCdevice_Lock(device);
     /* If the device is disconnected, go right to stopped. */
-    if(!device->Connected)
+    if(!ATOMIC_LOAD(&device->Connected, almemory_order_acquire))
     {
         for(i = 0;i < n;i++)
         {