gl/wayland: fix wayland event source burning CPU

Commit c71dd72b "gl/wayland: fix glib mainloop integration" was overeager
in removing the poll result test from the check function. This caused
dispatch to be called even if no new events are available on the
Wayland connection, which in turn would wake up the glib mainloop,
causing effectively a tight loop without ever blocking on the poll.

Fixes #603

diff --git a/gst-libs/gst/gl/wayland/wayland_event_source.c b/gst-libs/gst/gl/wayland/wayland_event_source.c
index 3f9d482..553125e 100644 (file)
--- a/gst-libs/gst/gl/wayland/wayland_event_source.c
+++ b/gst-libs/gst/gl/wayland/wayland_event_source.c
@@ -151,8 +151,12 @@ wayland_event_source_check (GSource * base)
 
   source->reading = FALSE;
 
-  if (wl_display_read_events (source->display) == 0)
-    return TRUE;
+  if (source->pfd.revents & G_IO_IN) {
+    if (wl_display_read_events (source->display) == 0)
+      return TRUE;
+  } else {
+    wl_display_cancel_read (source->display);
+  }
 
   return FALSE;
 }