frame clock: Use compositor refresh rate info even if presentation time not set

On my X11 + nvidia setup gnome-shell doesn't report presentation times.
However it does report refresh rate. We were mostly using this in our
calculation except when computing predicted presentation time, were
it fell back on the default 60Hz.

(cherry picked from commit f1215d2d776dd44e389b7c141eaac3f72942deae)

1 files changed, 15 insertions, 10 deletions

diff --git a/gdk/gdkframeclock.c b/gdk/gdkframeclock.c
index 075e42ef8f..bb61feaf83 100644
--- a/gdk/gdkframeclock.c
+++ b/gdk/gdkframeclock.c
@@ -568,16 +568,12 @@ gdk_frame_clock_get_refresh_info (GdkFrameClock *frame_clock,
                                   gint64        *presentation_time_return)
 {
   gint64 frame_counter;
+  gint64 default_refresh_interval = DEFAULT_REFRESH_INTERVAL;
 
   g_return_if_fail (GDK_IS_FRAME_CLOCK (frame_clock));
 
   frame_counter = gdk_frame_clock_get_frame_counter (frame_clock);
 
-  if (presentation_time_return)
-    *presentation_time_return = 0;
-  if (refresh_interval_return)
-    *refresh_interval_return = DEFAULT_REFRESH_INTERVAL;
-
   while (TRUE)
     {
       GdkFrameTimings *timings = gdk_frame_clock_get_timings (frame_clock, frame_counter);
@@ -585,19 +581,21 @@ gdk_frame_clock_get_refresh_info (GdkFrameClock *frame_clock,
       gint64 refresh_interval;
 
       if (timings == NULL)
-        return;
+        break;
 
       refresh_interval = timings->refresh_interval;
       presentation_time = timings->presentation_time;
 
+      if (refresh_interval == 0)
+        refresh_interval = default_refresh_interval;
+      else
+        default_refresh_interval = refresh_interval;
+
       if (presentation_time != 0)
         {
           if (presentation_time > base_time - MAX_HISTORY_AGE &&
               presentation_time_return)
             {
-              if (refresh_interval == 0)
-                refresh_interval = DEFAULT_REFRESH_INTERVAL;
-
               if (refresh_interval_return)
                 *refresh_interval_return = refresh_interval;
 
@@ -606,13 +604,20 @@ gdk_frame_clock_get_refresh_info (GdkFrameClock *frame_clock,
 
               if (presentation_time_return)
                 *presentation_time_return = presentation_time;
+
+              return;
             }
 
-          return;
+          break;
         }
 
       frame_counter--;
     }
+
+  if (presentation_time_return)
+    *presentation_time_return = 0;
+  if (refresh_interval_return)
+    *refresh_interval_return = default_refresh_interval;
 }
 
 void