[alsa-devel] [PATCH] pcm, rate: hw_avail must not be negative before starting the stream

[Alexander E. Patrakov]

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 at gmail.com>
---

As suggested by Takashi Iwai.

 src/pcm/pcm_rate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 736d558..c76db25 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;
-- 
2.1.0