According to the comments in src/glx/glxcurrent.c __glXGetCurrentContext() always returns a valid pointer. If no context is made current, it will contain dummyContext. Thus a test for NULL will always fail. https://lists.freedesktop.org/archives/mesa-dev/2016-April/113962.html Signed-off-by: Stefan Dirsch <sndirsch@suse.de> Reviewed-by: Egbert Eich <eich@freedesktop.org> Reviewed-by: Emil Velikov <emil.velikov@collabora.com>