From d7b5484f51f271a63202aeffa6cb3a01b235b713 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Tue, 23 Dec 2014 03:59:14 +0100
Subject: [PATCH] ao_alsa: fix resuming from suspend mode

snd_pcm_prepare() was not always called, which could result in an
infinite loop.

Whether snd_pcm_prepare() was actually called depended on whether the
device was a hw device (or other characteristics; depending on
snd_pcm_hw_params_can_pause()), and required real suspend (annoying for
testing), so it was somewhat tricky to reproduce without knowing these
things.
---
 audio/out/ao_alsa.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/audio/out/ao_alsa.c b/audio/out/ao_alsa.c
index 5a0c9071ec..9069494f01 100644
--- a/audio/out/ao_alsa.c
+++ b/audio/out/ao_alsa.c
@@ -745,7 +745,7 @@ static void audio_pause(struct ao *ao)
 alsa_error: ;
 }
 
-static void audio_resume(struct ao *ao)
+static void resume_device(struct ao *ao)
 {
     struct priv *p = ao->priv;
     int err;
@@ -756,6 +756,12 @@ static void audio_resume(struct ao *ao)
         while ((err = snd_pcm_resume(p->alsa)) == -EAGAIN)
             sleep(1);
     }
+}
+
+static void audio_resume(struct ao *ao)
+{
+    struct priv *p = ao->priv;
+    int err;
 
     if (p->can_pause) {
         if (snd_pcm_state(p->alsa) == SND_PCM_STATE_PAUSED) {
@@ -807,10 +813,12 @@ static int play(struct ao *ao, void **data, int samples, int flags)
 
         if (res == -EINTR || res == -EAGAIN) { /* retry */
             res = 0;
-        } else if (res == -ESTRPIPE) {  /* suspend */
-            audio_resume(ao);
         } else if (res < 0) {
-            MP_ERR(ao, "Write error: %s\n", snd_strerror(res));
+            if (res == -ESTRPIPE) {  /* suspend */
+                resume_device(ao);
+            } else {
+                MP_ERR(ao, "Write error: %s\n", snd_strerror(res));
+            }
             res = snd_pcm_prepare(p->alsa);
             int err = res;
             CHECK_ALSA_ERROR("pcm prepare error");