From a3c4f854895a87aab68c39843318b8df379f9275 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Tue, 6 Oct 2015 18:50:56 -0700
Subject: [PATCH] ALSA: fix deadlock under some circumstances

If the write_callback came upon an error during the prepare
phase, and never wrote any frames to the hardware buffer,
and another thread tried to soundio_outstream_destroy, this
would cause a deadlock.

This is now fixed.
---
 src/alsa.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/alsa.cpp b/src/alsa.cpp
index d1f675c..c9a60e1 100644
--- a/src/alsa.cpp
+++ b/src/alsa.cpp
@@ -1047,6 +1047,8 @@ static void outstream_thread_run(void *arg) {
 
                 if ((snd_pcm_uframes_t)avail == osa->buffer_size_frames) {
                     outstream->write_callback(outstream, 0, avail);
+                    if (!osa->thread_exit_flag.test_and_set())
+                        return;
                     continue;
                 }