From: Alexander E. Patrakov <patrakov@gmail.com>
Date: Mon, 15 Sep 2014 14:17:47 +0000 (+0600)
Subject: pcm, rate: hw_avail must not be negative before starting the stream
X-Git-Tag: v1.0.29~40
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=048568bbea700dfd9921b40321f8d5aa7e5ef417;p=alsa-lib.git

pcm, rate: hw_avail must not be negative before starting the stream

If it is, then it means most likely the driver problem, so we should
return error immediately instead.

Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---

diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 736d5583..c76db25b 100644
--- a/src/pcm/pcm_rate.c
+++ b/src/pcm/pcm_rate.c
@@ -1069,7 +1069,10 @@ static int snd_pcm_rate_start(snd_pcm_t *pcm)
 	gettimestamp(&rate->trigger_tstamp, pcm->tstamp_type);
 
 	avail = snd_pcm_mmap_playback_hw_avail(rate->gen.slave);
-	if (avail <= 0) {
+	if (avail < 0) /* can't happen on healthy drivers */
+		return -EBADFD;
+
+	if (avail == 0) {
 		/* postpone the trigger since we have no data committed yet */
 		rate->start_pending = 1;
 		return 0;