As a DDX may declare offload support without supporting DRI2
(because it is using an alternative acceleration mechanism like DRI3),
when iterating the list of offload_source Screens to find a matching
DRI2 provider we need to check before assuming it is DRI2 capable.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88514
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>