--- ./src/pcm/pcm.c.orig	2016-08-10 19:39:59.881564371 +0200
+++ ./src/pcm/pcm.c	2016-08-10 19:40:04.211539997 +0200
@@ -2544,6 +2544,7 @@
 	pcm->fast_op_arg = pcm;
 	INIT_LIST_HEAD(&pcm->async_handlers);
 #ifdef THREAD_SAFE_API
+	pcm->thread_safe = 1;
 	pthread_mutex_init(&pcm->lock, NULL);
 	{
 		static int default_thread_safe = -1;