$NetBSD: patch-aa,v 1.1.1.1 2004/07/26 17:05:05 dillo Exp $

--- sys/sdl/sdl.c.orig	2001-09-17 18:40:14.000000000 +0200
+++ sys/sdl/sdl.c
@@ -441,6 +441,8 @@ static int sound = 1;
 static int samplerate = 44100;
 static int stereo = 1;
 static volatile int audio_done;
+static SDL_sem *pcm_rsem, *pcm_wsem;
+static int atexit_done = 0;
 
 rcvar_t pcm_exports[] =
 {
@@ -453,8 +455,16 @@ rcvar_t pcm_exports[] =
 
 static void audio_callback(void *blah, byte *stream, int len)
 {
+	SDL_SemWait(pcm_rsem);
 	memcpy(stream, pcm.buf, len);
-	audio_done = 1;
+	SDL_SemPost(pcm_wsem);
+}
+
+
+static void audio_atexit(void)
+{
+	if (pcm_wsem)
+		SDL_SemPost(pcm_rsem);
 }
 
 
@@ -466,6 +476,13 @@ void pcm_init()
 	if (!sound) return;
 	
 	SDL_InitSubSystem(SDL_INIT_AUDIO);
+	/* XXX: check for NULL */
+	pcm_rsem = SDL_CreateSemaphore(0);
+	pcm_wsem = SDL_CreateSemaphore(0);
+	if (!atexit_done) {
+		atexit(audio_atexit);
+		atexit_done = 1;
+	}
 	as.freq = samplerate;
 	as.format = AUDIO_U8;
 	as.channels = 1 + stereo;
@@ -491,16 +508,20 @@ int pcm_submit()
 {
 	if (!pcm.buf) return 0;
 	if (pcm.pos < pcm.len) return 1;
-	while (!audio_done)
-		SDL_Delay(4);
-	audio_done = 0;
+	SDL_SemPost(pcm_rsem);
+	SDL_SemWait(pcm_wsem);
 	pcm.pos = 0;
 	return 1;
 }
 
 void pcm_close()
 {
-	if (sound) SDL_CloseAudio();
+	if (sound) {
+		SDL_CloseAudio();
+		SDL_DestroySemaphore(pcm_rsem);
+		SDL_DestroySemaphore(pcm_wsem);
+		pcm_rsem = pcm_wsem = 0;
+	}
 }