fix(audio): unbreak bluetooth audio - no sound, and freeze on disconnect

skeleton/SYSTEM/tg5040/paks/MinUI.pak/launch.sh

@@ -26,6 +26,15 @@ export HOOKS_PATH="$USERDATA_PATH/.hooks"
 export DATETIME_PATH="$SHARED_USERDATA_PATH/datetime.txt"
 export HOME="$USERDATA_PATH"
 
+# alsa-lib >= 1.1.2 guards each snd_pcm_t with a recursive lock. On the
+# bluealsa sink that lock ends up held by the thread that opened the PCM and
+# never released, so SDL's audio thread blocks inside libasound forever: no
+# sound over bluetooth, and SDL_CloseAudioDevice() then deadlocks the game
+# loop joining that thread when the headset disconnects. We never touch one
+# PCM from two threads at once (SDL serialises that itself), so alsa's own
+# locking buys us nothing - turn it off.
+export LIBASOUND_THREAD_SAFE=0
+
 #######################################
 
 if [ -f "/tmp/poweroff" ]; then

skeleton/SYSTEM/tg5050/paks/MinUI.pak/launch.sh

@@ -26,6 +26,15 @@ export HOOKS_PATH="$USERDATA_PATH/.hooks"
 export DATETIME_PATH="$SHARED_USERDATA_PATH/datetime.txt"
 export HOME="$USERDATA_PATH"
 
+# alsa-lib >= 1.1.2 guards each snd_pcm_t with a recursive lock. On the
+# bluealsa sink that lock ends up held by the thread that opened the PCM and
+# never released, so SDL's audio thread blocks inside libasound forever: no
+# sound over bluetooth, and SDL_CloseAudioDevice() then deadlocks the game
+# loop joining that thread when the headset disconnects. We never touch one
+# PCM from two threads at once (SDL serialises that itself), so alsa's own
+# locking buys us nothing - turn it off.
+export LIBASOUND_THREAD_SAFE=0
+
 #######################################
 
 if [ -f "/tmp/poweroff" ]; then

workspace/all/minarch/ma_core.c

@@ -152,10 +152,9 @@ void Core_reset(void) {
 	Rewind_on_state_change();
 }
 void Core_unload(void) {
-	// Disabling this is a dumb hack for bluetooth, we should really be using 
-	// bluealsa with --keep-alive=-1 - but SDL wont reconnect the stream on next start.
-	// Reenable as soon as we have a more recent SDL available, if ever.
-	//SND_quit();
+	// Audio teardown deliberately does not happen here: SND_quit() frees the
+	// sample buffer, and the core can still emit audio from unload_game(),
+	// which runs later in Core_quit(). It is done at the end of main().
 }
 void Core_quit(void) {
 	if (core.initialized) {

workspace/all/minarch/minarch.c

@@ -367,10 +367,7 @@ int main(int argc , char* argv[]) {
 	PWR_quit();
 	VIB_quit();
 	SND_removeDeviceWatcher();
-	// Disabling this is a dumb hack for bluetooth, we should really be using 
-	// bluealsa with --keep-alive=-1 - but SDL wont reconnect the stream on next start.
-	// Reenable as soon as we have a more recent SDL available, if ever.
-	//SND_quit();
+	SND_quit();
 	PAD_quit();
 	GFX_quit();
 	Menu_waitScreenshot();