tree 6abdb46062486a9009fc2226abb0f778011dc22e
parent f22e6e847115abc3a0e2ad7bb18d243d42275af1
author Jesse Barnes <jbarnes@virtuousgeek.org> 1427923377 -0700
committer Jani Nikula <jani.nikula@intel.com> 1428410190 +0300

drm/i915/vlv: save/restore the power context base reg

Some BIOSes (e.g. the one on the Minnowboard) don't save/restore this
reg.  If it's unlocked, we can just restore the previous value, and if
it's locked (in case the BIOS re-programmed it for us) the write will be
ignored and we'll still have "did it move" sanity check in the PM code to
warn us if something is still amiss.

References: https://bugs.freedesktop.org/show_bug.cgi?id=89611
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Darren Hart <dvhart@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>