From: Andre Noll <maan@systemlinux.org>
Date: Fri, 15 Jan 2010 19:19:30 +0000 (+0100)
Subject: alsa: Replace check for pending frames on eof by a barrier.
X-Git-Tag: v0.4.2~89
X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=commitdiff_plain;h=9366a7ddafa4738db0528050ff9080a5f15a3ad7

alsa: Replace check for pending frames on eof by a barrier.

The old code could lead to a an endless loop where the alsa writer
would never be unscheduled.
---

diff --git a/alsa_write.c b/alsa_write.c
index 8bc12a90..3c8d063f 100644
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -54,6 +54,7 @@ struct private_alsa_write_data {
 	 * decoder of the writer node group.
 	 */
 	unsigned channels;
+	struct timeval drain_barrier;
 };
 
 /* Install PCM software and hardware configuration. */
@@ -217,7 +218,7 @@ static void alsa_write_post_select(__a_unused struct sched *s,
 	struct btr_node *btrn = wn->btrn;
 	char *data;
 	size_t bytes;
-	snd_pcm_sframes_t frames, avail;
+	snd_pcm_sframes_t frames;
 	int ret;
 
 again:
@@ -233,10 +234,14 @@ again:
 		if (!pad->handle)
 			goto err;
 		/* wait until pending frames are played */
-		avail = snd_pcm_avail_update(pad->handle);
-		if (avail + 1000 > pad->buffer_frames)
+		if (pad->drain_barrier.tv_sec == 0) {
+			PARA_DEBUG_LOG("waiting for device to drain\n");
+			tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
+				&pad->drain_barrier);
+			return;
+		}
+		if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 			goto err;
-		PARA_DEBUG_LOG("waiting for device to drain\n");
 		return;
 	}
 	if (!pad->handle) {