Recoomendation from Lennart Poettering:

I guess I don't have to mention that, but ALSA_WaitAudio() is
pure evil, and just broken. getpid() returns pids, not tids. You get
those via gettid(). But I'd recommend dropping that entirely. It's
just broken.

src/audio/alsa/SDL_alsa_audio.c

@@ -251,17 +251,7 @@ AudioBootStrap ALSA_bootstrap = {
 /* This function waits until it is possible to write a full sound buffer */
 static void ALSA_WaitAudio(_THIS)
 {
-	/* Check to see if the thread-parent process is still alive */
-	{ static int cnt = 0;
-		/* Note that this only works with thread implementations 
-		   that use a different process id for each thread.
-		*/
-		if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
-			if ( kill(parent, 0) < 0 ) {
-				this->enabled = 0;
-			}
-		}
-	}
+	/* We're in blocking mode, so there's nothing to do here */
 }
 
 
@@ -601,9 +591,6 @@ static int ALSA_OpenAudio(_THIS, SDL_AudioSpec *spec)
 	}
 	SDL_memset(mixbuf, spec->silence, spec->size);
 
-	/* Get the parent process id (we're the parent of the audio thread) */
-	parent = getpid();
-
 	/* Switch to blocking mode for playback */
 	SDL_NAME(snd_pcm_nonblock)(pcm_handle, 0);
 

src/audio/alsa/SDL_alsa_audio.h

@@ -35,17 +35,13 @@ struct SDL_PrivateAudioData {
 	/* The audio device handle */
 	snd_pcm_t *pcm_handle;
 
-	/* The parent process id, to detect when application quits */
-	pid_t parent;
-
 	/* Raw mixing buffer */
 	Uint8 *mixbuf;
 	int    mixlen;
 };
 
 /* Old variable names */
 #define pcm_handle		(this->hidden->pcm_handle)
-#define parent			(this->hidden->parent)
 #define mixbuf			(this->hidden->mixbuf)
 #define mixlen			(this->hidden->mixlen)