Commits
Jani Nikula committed 2059ac3b130
drm/i915: fix backlight after resume on 855gm
Some 855gm models (at least ThinkPad X40) regressed because of
commit b0cd324faed23d10d66ba6ade66579c681feef6f
Author: Jani Nikula <jani.nikula@intel.com>
Date: Wed Nov 12 16:25:43 2014 +0200
drm/i915: don't save/restore backlight hist ctl registers
which tried to make our driver more robust by not blindly saving and
restoring registers, but it failed to take into account
commit 0eb96d6ed38430b72897adde58f5477a6b71757a
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date: Wed Oct 14 12:33:41 2009 -0700
drm/i915: save/restore BLC histogram control reg across suspend/resume
Fix the regression by enabling hist ctl on gen2.
v2: Improved the comment.
v3: Improved the comment, again.
Reported-and-tested-by: Philipp Gesang <phg@phi-gamma.net>
References: http://mid.gmane.org/20150623222648.GD12335@acheron
Fixes: b0cd324faed2 ("drm/i915: don't save/restore backlight hist ctl registers")
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>