We only have sufficient information for accurate (sub-frame) timestamping
when the modesetting is under our control.
Reported-by: NChris Clayton <chris2553@googlemail.com>
Tested-by: NChris Clayton <chris2553@googlemail.com>
Reviewed-by: NMario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>