diff --git a/cogl/cogl-debug.c b/cogl/cogl-debug.c
index 37ae266af..7d9e1a746 100644
--- a/cogl/cogl-debug.c
+++ b/cogl/cogl-debug.c
@@ -48,6 +48,7 @@ static const GDebugKey cogl_log_debug_keys[] = {
   { "batching", COGL_DEBUG_BATCHING },
   { "matrices", COGL_DEBUG_MATRICES },
   { "draw", COGL_DEBUG_DRAW },
+  { "opengl", COGL_DEBUG_OPENGL },
   { "pango", COGL_DEBUG_PANGO },
 };
 static const int n_cogl_log_debug_keys =
@@ -114,6 +115,7 @@ _cogl_parse_debug_string (const char *value,
       OPT ("force-scanline-paths:", "use a scanline based path rasterizer");
       OPT ("dump-atlas-image:", "dump atlas changes to an image file");
       OPT ("disable-atlas:", "disable texture atlasing");
+      OPT ("opengl:", "traces some select OpenGL calls");
       g_printerr ("\n%28s\n", "Special debug values:");
       OPT ("all:", "Enables all non-behavioural debug options");
       OPT ("verbose:", "Enables all non-behavioural debug options");
diff --git a/cogl/cogl-debug.h b/cogl/cogl-debug.h
index 146db9cce..775625dae 100644
--- a/cogl/cogl-debug.h
+++ b/cogl/cogl-debug.h
@@ -45,7 +45,8 @@ typedef enum {
   COGL_DEBUG_FORCE_SCANLINE_PATHS = 1 << 14,
   COGL_DEBUG_ATLAS            = 1 << 15,
   COGL_DEBUG_DUMP_ATLAS_IMAGE = 1 << 16,
-  COGL_DEBUG_DISABLE_ATLAS    = 1 << 17
+  COGL_DEBUG_DISABLE_ATLAS    = 1 << 17,
+  COGL_DEBUG_OPENGL           = 1 << 18
 } CoglDebugFlags;
 
 #ifdef COGL_ENABLE_DEBUG
diff --git a/cogl/cogl-framebuffer.c b/cogl/cogl-framebuffer.c
index 2b35e1114..6bf6c531c 100644
--- a/cogl/cogl-framebuffer.c
+++ b/cogl/cogl-framebuffer.c
@@ -681,6 +681,12 @@ _cogl_framebuffer_flush_state (CoglHandle handle,
         gl_viewport_y = framebuffer->height -
           (framebuffer->viewport_y + framebuffer->viewport_height);
 
+      COGL_NOTE (OPENGL, "Calling glViewport(%d, %d, %d, %d)",
+                 framebuffer->viewport_x,
+                 gl_viewport_y,
+                 framebuffer->viewport_width,
+                 framebuffer->viewport_height);
+
       GE (glViewport (framebuffer->viewport_x,
                       gl_viewport_y,
                       framebuffer->viewport_width,