The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/kernel/+/e29b05541c09668d74f0c47cb5a22acd285b1b1a

commit e29b05541c09668d74f0c47cb5a22acd285b1b1a
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Fri Jan 18 20:29:03 2013

BACKPORT: drm/i915: don't save/restore DSPARB on gen5+

Because the register does not exist in gen5+.

This patch solves "unclaimed register" messages on Haswell after
suspend/resume.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit 8de0add7231f5747f192c1ed35fd792a866c885b)
Signed-off-by: Stphane Marchesin <marcheu@chromium.org>

BUG= chromium:600866 
TEST=compiles

Change-Id: I44f4fc2fc929d977e184f5da95935012f594f21c
Reviewed-on: https://chromium-review.googlesource.com/337332
Commit-Ready: Ilja Friedel <ihf@chromium.org>
Tested-by: Ilja Friedel <ihf@chromium.org>
Reviewed-by: Ilja Friedel <ihf@chromium.org>

[modify] https://crrev.com/e29b05541c09668d74f0c47cb5a22acd285b1b1a/drivers/gpu/drm/i915/i915_suspend.c