spiceqxl_audio: Stop the playback channel if there is nothing to play

This lets the client free the audio resources when an audio application
is not actually playing anything, typically because playback is paused.
This matches QEMU's behavior.
As a side benefit it stops the client's mm-time from being stuck (due
to the audio backend's delay updates being applied to the mm-time of
the last audio message) which lets video streams play in this situation.

Signed-off-by: Francois Gouget <fgouget@codeweavers.com>

1 files changed, 21 insertions, 7 deletions

diff --git a/src/spiceqxl_audio.c b/src/spiceqxl_audio.c
index 8d187b7..52a45f0 100644
--- a/src/spiceqxl_audio.c
+++ b/src/spiceqxl_audio.c
@@ -46,6 +46,7 @@
        and feed ahead into the Spice server (up to FEED_BUFFER_PERIODS).
 */
 
+#define IDLE_MS              300
 #define PERIOD_MS            10
 #define READ_BUFFER_PERIODS  2
 #define FEED_BUFFER_PERIODS  8
@@ -72,7 +73,7 @@ struct audio_data {
     int fifo_count;
     int closed_fifos;
     SpiceTimer *wall_timer;
-    int wall_timer_live;
+    int wall_timer_type;
     int dir_watch;
     int fifo_dir_watch;
     SpiceWatch *fifo_dir_qxl_watch;
@@ -279,9 +280,9 @@ static void read_from_fifos(int fd, int event, void *opaque)
     int i;
     int maxlen = 0;
 
-    if (data->wall_timer_live) {
+    if (data->wall_timer_type) {
         qxl->core->timer_cancel(data->wall_timer);
-        data->wall_timer_live = 0;
+        data->wall_timer_type = 0;
     }
 
     for (i = 0; i < data->fifo_count; i++) {
@@ -333,12 +334,16 @@ static void read_from_fifos(int fd, int event, void *opaque)
     if (!process_fifos(qxl, data, maxlen)) {
         /* There is still some fifo data to process */
         qxl->core->timer_start(data->wall_timer, PERIOD_MS);
-        data->wall_timer_live = 1;
+        data->wall_timer_type = PERIOD_MS;
 
     } else if (data->fifo_count) {
         /* All the fifo data was processed. Wait for more */
         start_watching(qxl);
 
+        /* But none may arrive so stop processing if that happens */
+        qxl->core->timer_start(data->wall_timer, IDLE_MS);
+        data->wall_timer_type = IDLE_MS;
+
     } else if (data->active) {
         /* There is no open fifo anymore */
         spice_server_playback_stop(&qxl->playback_sin);
@@ -361,14 +366,23 @@ static void start_watching(qxl_screen_t *qxl)
     }
 }
 
+/* a helper for read_from_fifos() */
 static void wall_ticker(void *opaque)
 {
     qxl_screen_t *qxl = opaque;
     struct audio_data *data = qxl->playback_opaque;
 
-    data->wall_timer_live = 0;
-
-    read_from_fifos(-1, 0, qxl);
+    if (data->wall_timer_type == IDLE_MS) {
+        /* The audio is likely paused in the application(s) */
+        if (data->active) {
+            spice_server_playback_stop(&qxl->playback_sin);
+            data->active = 0;
+        }
+        data->wall_timer_type = 0;
+    } else {
+        data->wall_timer_type = 0;
+        read_from_fifos(-1, 0, qxl);
+    }
 }
 
 #if defined(HAVE_SYS_INOTIFY_H)