From cee7e2f6b271c36ee0bf3cc3836cbde77301d10e Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 17 Dec 2013 14:34:50 +0000
Subject: [PATCH] drm/i915: Use the correct GMCH_CTRL register for Sandybridge+
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commit a885b3ccc74d8e38074e1c43a47c354c5ea0b01e upstream.

The GMCH_CTRL register (or MGCC in the spec) is at a different address
on Sandybridge, and the address to which we currently write to is
undefined. These stray writes appear to upset (hard hang) my Ivybridge
machine whilst it is in UEFI mode.

Note that the register is still marked as locked RO on Sandybridge, so
vgaarb is still dysfunctional.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2: add definition of SNB_GMCH_CTRL in i915_reg.h]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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