When leaving 3D games such as quake3 or sauerbraten, a cursor may stay on the
screen. This is caused by one run of SW rendering for the SD, even though the
SD was attached to the VCP and thus has HW rendering capabilities.
Check for the SD's attachment (like in all other functions) before deciding on
SW or HW rendering.
X.Org Bug 16805 <http://bugs.freedesktop.org/show_bug.cgi?id=16805>
Signed-off-by: Peter Hutterer <peter.hutterer@redhat.com>
(cherry picked from commit bb072019fa)