[alsa-devel] [PATCH] PCM: snd_pcm_dmix_drain() maybe blocked after suspend and resume

[Shengjiu Wang]

After suspend and resume, the alsa driver is stopped. But if alsa-lib run
into snd_pcm_dmix_drain(), it need to wait avail >= pcm->stop_threshold,
otherwise, it will not exit the loop, so finally it is blocked at poll() of
snd_pcm_wait_nocheck(pcm, -1).
This patch is to add state check after snd_pcm_wait_nocheck(pcm, -1), if
the state is SND_PCM_STATE_SUSPENDED, then return error.

Signed-off-by: Shengjiu Wang <shengjiu.wang at freescale.com>
---
 src/pcm/pcm_dmix.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c
index babde6a..0cc318e 100644
--- a/src/pcm/pcm_dmix.c
+++ b/src/pcm/pcm_dmix.c
@@ -647,6 +647,12 @@ static int snd_pcm_dmix_drain(snd_pcm_t *pcm)
 		if (dmix->state == SND_PCM_STATE_DRAINING) {
 			snd_pcm_dmix_sync_area(pcm);
 			snd_pcm_wait_nocheck(pcm, -1);
+			switch (snd_pcm_state(pcm)) {
+			case SND_PCM_STATE_SUSPENDED:
+				return -ESTRPIPE;
+			default:
+				break;
+			}
 			snd_pcm_direct_clear_timer_queue(dmix); /* force poll to wait */
 		}
 	} while (dmix->state == SND_PCM_STATE_DRAINING);
-- 
1.7.9.5