If a GPU reset occurs while a page flip has been submitted to the ring,
the flip will never complete once the ring has been reset.

The GPU reset can be detected by sampling the reset_counter before the
flip is submitted, and then while waiting for the flip, the sampled
counter is compared with the current reset_counter value.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
[danvet: Move the reset_counter assignment to an earlier place in
common code as discussed on the mailing list.]
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=60140Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>