This fixes a segfault when we attempt to call ds->ReuseBufferNotify() passing a Prime DRI2BufferPtr to the master backend. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80001 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Keith Packard <keithp@keithp.com>