pulsesink: Issue property change notification in streaming thread,

rather than PA thread.

pa_threaded_mainloop_lock() (a.o.) and by extension get_property should
not be done from a PA thread, but the latter may occur as a result of a
property change notification.  Fixes #571204 (though current situation
not ideal, e.g. post message rather than signal).

2 files changed, 9 insertions, 6 deletions

diff --git a/ext/pulse/pulsesink.c b/ext/pulse/pulsesink.c
index b167b43f..1d74aa23 100644
--- a/ext/pulse/pulsesink.c
+++ b/ext/pulse/pulsesink.c
@@ -269,6 +269,7 @@ gst_pulsesink_init (GstPulseSink * pulsesink, GstPulseSinkClass * klass)
   pulsesink->operation_success = FALSE;
   pulsesink->did_reset = FALSE;
   pulsesink->in_write = FALSE;
+  pulsesink->notify = 0;
 
   pulsesink->mainloop = pa_threaded_mainloop_new ();
   g_assert (pulsesink->mainloop);
@@ -621,13 +622,10 @@ gst_pulsesink_context_subscribe_cb (pa_context * c,
   /* Actually this event is also triggered when other properties of
    * the stream change that are unrelated to the volume. However it is
    * probably cheaper to signal the change here and check for the
-   * volume when the GObject property is read instead of querying it always.
-   *
-   * Lennart thinks this is a race because g_object_notify() is not
-   * thread safe and this function is run from a PA controlled
-   * thread. But folks on #gstreamer told me that was ok. */
+   * volume when the GObject property is read instead of querying it always. */
 
-  g_object_notify (G_OBJECT (pulsesink), "volume");
+  /* inform streaming thread to notify */
+  g_atomic_int_compare_and_exchange (&pulsesink->notify, 0, 1);
 }
 #endif
 
@@ -876,6 +874,10 @@ gst_pulsesink_write (GstAudioSink * asink, gpointer data, guint length)
   GstPulseSink *pulsesink = GST_PULSESINK (asink);
   size_t sum = 0;
 
+  /* FIXME post message rather than using a signal (as mixer interface) */
+  if (g_atomic_int_compare_and_exchange (&pulsesink->notify, 1, 0))
+    g_object_notify (G_OBJECT (pulsesink), "volume");
+
   pa_threaded_mainloop_lock (pulsesink->mainloop);
 
   pulsesink->in_write = TRUE;
diff --git a/ext/pulse/pulsesink.h b/ext/pulse/pulsesink.h
index eb8d43d2..70fd8a65 100644
--- a/ext/pulse/pulsesink.h
+++ b/ext/pulse/pulsesink.h
@@ -68,6 +68,7 @@ struct _GstPulseSink
 
   gboolean operation_success;
   gboolean did_reset, in_write;
+  gint notify;
 };
 
 struct _GstPulseSinkClass