diff --git a/rdpsnd_libao.c b/rdpsnd_libao.c
index 22c03c9..3744073 100644
--- a/rdpsnd_libao.c
+++ b/rdpsnd_libao.c
@@ -42,7 +42,8 @@ void
 libao_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv)
 {
 	/* We need to be called rather often... */
-	FD_SET(0, wfds);
+	if (o_device != NULL && !rdpsnd_queue_empty())
+		FD_SET(0, wfds);
 }
 
 void
diff --git a/rdpsnd_sgi.c b/rdpsnd_sgi.c
index 7903391..94f5836 100644
--- a/rdpsnd_sgi.c
+++ b/rdpsnd_sgi.c
@@ -45,7 +45,8 @@ void
 sgi_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv)
 {
 	/* We need to be called rather often... */
-	FD_SET(0, wfds);
+	if (output_port != (ALport) 0 && !rdpsnd_queue_empty())
+		FD_SET(0, wfds);
 }
 
 void