volume: added PIPE_EVENT_MIXER

Flush the hardware volume cache, and send the MIXER idle event.  This
allows mixer plugins to detect volume changes.

2 files changed, 19 insertions, 0 deletions

diff --git a/src/event_pipe.h b/src/event_pipe.h
index 33f92d440..4614ef25c 100644
--- a/src/event_pipe.h
+++ b/src/event_pipe.h
@@ -41,6 +41,9 @@ enum pipe_event {
 	/** SIGHUP received: reload configuration, roll log file */
 	PIPE_EVENT_RELOAD,
 
+	/** a hardware mixer plugin has detected a change */
+	PIPE_EVENT_MIXER,
+
 	PIPE_EVENT_MAX
 };
 
diff --git a/src/volume.c b/src/volume.c
index 8b33f592d..1be0705af 100644
--- a/src/volume.c
+++ b/src/volume.c
@@ -27,6 +27,7 @@
 #include "mixer_control.h"
 #include "mixer_all.h"
 #include "mixer_type.h"
+#include "event_pipe.h"
 
 #include <glib.h>
 
@@ -47,6 +48,19 @@ static int last_hardware_volume = -1;
 /** the age of #last_hardware_volume */
 static GTimer *hardware_volume_timer;
 
+/**
+ * Handler for #PIPE_EVENT_MIXER.
+ */
+static void
+mixer_event_callback(void)
+{
+	/* flush the hardware volume cache */
+	last_hardware_volume = -1;
+
+	/* notify clients */
+	idle_add(IDLE_MIXER);
+}
+
 void volume_finish(void)
 {
 	g_timer_destroy(hardware_volume_timer);
@@ -55,6 +69,8 @@ void volume_finish(void)
 void volume_init(void)
 {
 	hardware_volume_timer = g_timer_new();
+
+	event_pipe_register(PIPE_EVENT_MIXER, mixer_event_callback);
 }
 
 int volume_level_get(void)