[cogl] winsys-glx: Don't assume that copy_sub_buffer is synchronized

[Robert Bragg <rbragg src gnome org>]

commit fd31da45e22c276ac31917c6f87ef71d0e7fa931
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Wed Mar 14 11:50:58 2012 +0100

    winsys-glx: Don't assume that copy_sub_buffer is synchronized
    
    We initially assumed that copy_sub_buffer is synchronized on
    which is only the case for a subset of GPUs for example it is not
    synchronized on INTEL gen6 and gen7, so we remove this assumption
    for now.
    
    We should have a specific driver / GPU whitelist if we want to enable
    this.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=669122
    
    Reviewed-by: Robert Bragg <robert linux intel com>
    Reviewed-by: Neil Roberts <neil linux intel com>

 cogl/winsys/cogl-winsys-glx-feature-functions.h |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/cogl/winsys/cogl-winsys-glx-feature-functions.h b/cogl/winsys/cogl-winsys-glx-feature-functions.h
index b903ebd..71fd827 100644
--- a/cogl/winsys/cogl-winsys-glx-feature-functions.h
+++ b/cogl/winsys/cogl-winsys-glx-feature-functions.h
@@ -89,7 +89,15 @@ COGL_WINSYS_FEATURE_BEGIN (copy_sub_buffer,
                            "copy_sub_buffer\0",
                            0,
                            0,
+/* We initially assumed that copy_sub_buffer is synchronized on
+ * which is only the case for a subset of GPUs for example it is not
+ * synchronized on INTEL gen6 and gen7, so we remove this assumption
+ * for now
+ */
+#if 0
                            COGL_WINSYS_FEATURE_SWAP_REGION_SYNCHRONIZED)
+#endif
+                           0)
 COGL_WINSYS_FEATURE_FUNCTION (void, glXCopySubBuffer,
                               (Display *dpy,
                                GLXDrawable drawable,