X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=oss_write.c;h=5b910742e3ada1ac084bac89183d3b8e75d03852;hp=d4bfd446ab845ef1b381201bccf091fadfae96c0;hb=5414dfd4356e63634f1a4e94382d14e200759d18;hpb=2d61a8005c74e9849ef53cd06113edf23cf72474

diff --git a/oss_write.c b/oss_write.c
index d4bfd446..5b910742 100644
--- a/oss_write.c
+++ b/oss_write.c
@@ -31,6 +31,29 @@ struct private_oss_write_data {
 	int bytes_per_frame;
 };
 
+/*
+ * We keep one bit of static storage to make sure only one instance of the oss
+ * writer is running at any given time.
+ */
+static bool sound_device_busy;
+
+static bool sound_device_is_busy(void)
+{
+	return sound_device_busy;
+}
+
+static void set_sound_device_busy(void)
+{
+	assert(!sound_device_busy);
+	sound_device_busy = true;
+}
+
+static void set_sound_device_idle(void)
+{
+	assert(sound_device_busy);
+	sound_device_busy = false;
+}
+
 static int get_oss_format(enum sample_format sf)
 {
 	switch (sf) {
@@ -50,7 +73,7 @@ static void oss_pre_select(struct sched *s, void *context)
 	struct private_oss_write_data *powd = wn->private_data;
 	int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 
-	if (ret == 0)
+	if (ret == 0 || (sound_device_is_busy() && !powd))
 		return;
 	if (ret < 0 || !powd)
 		return sched_min_delay(s);
@@ -65,6 +88,7 @@ static void oss_close(struct writer_node *wn)
 		return;
 	close(powd->fd);
 	free(powd);
+	set_sound_device_idle();
 }
 
 /*
@@ -174,12 +198,16 @@ static int oss_post_select(__a_unused struct sched *s, void *context)
 		goto out;
 	if (!powd) {
 		int32_t rate, ch, format;
+
+		if (sound_device_is_busy())
+			return 0;
 		get_btr_sample_rate(btrn, &rate);
 		get_btr_channels(btrn, &ch);
 		get_btr_sample_format(btrn, &format);
 		ret = oss_init(wn, rate, ch, format);
 		if (ret < 0)
 			goto out;
+		set_sound_device_busy();
 		return 0;
 	}
 	btr_merge(btrn, wn->min_iqs);