diff --git a/cogl.h.in b/cogl.h.in
index 188af09cd..a671aa00d 100644
--- a/cogl.h.in
+++ b/cogl.h.in
@@ -193,8 +193,8 @@ void            cogl_ortho                    (float left,
                                                float near,
                                                float far);
 
-/**
- * cogl_setup_viewport:
+/*
+ * _cogl_setup_viewport:
  * @width: Width of the viewport
  * @height: Height of the viewport
  * @fovy: Field of view angle in degrees
@@ -208,9 +208,11 @@ void            cogl_ortho                    (float left,
  * with one that has a viewing angle of @fovy along the y-axis and a
  * view scaled according to @aspect along the x-axis. The view is
  * clipped according to @z_near and @z_far on the z-axis.
+ *
+ * This function is used only by Clutter.
  */
-void            cogl_setup_viewport           (guint               width,
-                                               guint               height,
+void            _cogl_setup_viewport          (guint        width,
+                                               guint        height,
                                                float        fovy,
                                                float        aspect,
                                                float        z_near,
diff --git a/common/cogl.c b/common/cogl.c
index adeb479d2..336303917 100644
--- a/common/cogl.c
+++ b/common/cogl.c
@@ -475,12 +475,12 @@ cogl_viewport (guint width,
 }
 
 void
-cogl_setup_viewport (guint width,
-		     guint height,
-		     float fovy,
-		     float aspect,
-		     float z_near,
-		     float z_far)
+_cogl_setup_viewport (guint width,
+                      guint height,
+                      float fovy,
+                      float aspect,
+                      float z_near,
+                      float z_far)
 {
   float z_camera;
   CoglMatrix projection_matrix;
@@ -488,7 +488,7 @@ cogl_setup_viewport (guint width,
   GE( glViewport (0, 0, width, height) );
 
   /* For Ortho projection.
-   * _cogl_current_matrix_ortho (0, width << 16, 0,  height << 16,  -1 << 16, 1 << 16);
+   * _cogl_current_matrix_ortho (0, width, 0,  height, -1, 1);
    */
 
   cogl_perspective (fovy, aspect, z_near, z_far);
@@ -542,7 +542,7 @@ cogl_setup_viewport (guint width,
 }
 
 CoglFeatureFlags
-cogl_get_features ()
+cogl_get_features (void)
 {
   _COGL_GET_CONTEXT (ctx, 0);