From 0b3c52341d1d8d098f315302d6d3e1c40965493f Mon Sep 17 00:00:00 2001
From: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Date: Wed, 3 Jul 2019 17:09:51 +0300
Subject: [PATCH] alsa-sink: clear pollfd revents before poll

Always clear revents before calling snd_pcm_poll_descriptors_revents()
as the ALSA function will not clear out existing events.

Without this, playback restart fails in the following
scenario:

1. single stream PCM playback ongoing
2. system put to system suspend (S3), ALSA sink suspended
3. system resumes, ALSA sink restarted
4. upon first alsa-sink thread_func iteration, rtpoll
  revents still hass POLLERR bits set (due to the suspend)
5. execution goes to pa_alsa_recover_from_poll()
6. snd_pcm_drop() is called and PCM is restarted
7. process loops from (4) and playback is never recovered

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
---
 src/modules/alsa/alsa-sink.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/modules/alsa/alsa-sink.c b/src/modules/alsa/alsa-sink.c
index 4568a19c5..d96f19398 100644
--- a/src/modules/alsa/alsa-sink.c
+++ b/src/modules/alsa/alsa-sink.c
@@ -1915,6 +1915,7 @@ static void thread_func(void *userdata) {
             unsigned n;
 
             pollfd = pa_rtpoll_item_get_pollfd(u->alsa_rtpoll_item, &n);
+            pollfd->revents = 0;
 
             if ((err = snd_pcm_poll_descriptors_revents(u->pcm_handle, pollfd, n, &revents)) < 0) {
                 pa_log("snd_pcm_poll_descriptors_revents() failed: %s", pa_alsa_strerror(err));
-- 
2.21.0