[mutter/wip/carlosg/fix-multimonitor-buffer-age: 3/5] cogl/egl: Warn when we fail to query a buffer age.

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 6ee7c0f486e8827241fa881d398d97720346df46
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Oct 30 13:34:32 2019 +0100

    cogl/egl: Warn when we fail to query a buffer age.
    
    In order to avoid log spamming, just warn once it starts to happen, not
    on every frame for every onscreen. Just knowing that this is happening
    is a hint that something's going wrong.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/906

 cogl/cogl/winsys/cogl-winsys-egl.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/cogl/cogl/winsys/cogl-winsys-egl.c b/cogl/cogl/winsys/cogl-winsys-egl.c
index f2b439a67..6e7fb9781 100644
--- a/cogl/cogl/winsys/cogl-winsys-egl.c
+++ b/cogl/cogl/winsys/cogl-winsys-egl.c
@@ -697,12 +697,22 @@ _cogl_winsys_onscreen_get_buffer_age (CoglOnscreen *onscreen)
   CoglRendererEGL *egl_renderer = renderer->winsys;
   CoglOnscreenEGL *egl_onscreen = onscreen->winsys;
   EGLSurface surface = egl_onscreen->egl_surface;
+  static gboolean warned = FALSE;
   int age;
 
   if (!(egl_renderer->private_features & COGL_EGL_WINSYS_FEATURE_BUFFER_AGE))
     return 0;
 
-  eglQuerySurface (egl_renderer->edpy, surface, EGL_BUFFER_AGE_EXT, &age);
+  if (!eglQuerySurface (egl_renderer->edpy, surface, EGL_BUFFER_AGE_EXT, &age))
+    {
+      if (!warned)
+        g_critical ("Failed to query buffer age, got error %x", eglGetError ());
+      warned = TRUE;
+    }
+  else
+    {
+      warned = FALSE;
+    }
 
   return age;
 }