[PATCH 3.16.y-ckt 021/180] drm/i915/vlv: save/restore the power context base reg

[Luis Henriques]

3.16.7-ckt11 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>

commit 9c25210fd30991e68f93e2ec0857de2d967b5766 upstream.

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@xxxxxxxxxxxxxxxx>
Tested-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx>
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
Reviewed-by: Deepak S <deepak.s@xxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/i915/i915_drv.c | 2 ++
 drivers/gpu/drm/i915/i915_drv.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index e35e32f33e31..a458e8393378 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1071,6 +1071,7 @@ static void vlv_save_gunit_s0ix_state(struct drm_i915_private *dev_priv)
 	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
 	s->gu_ctl0		= I915_READ(VLV_GU_CTL0);
 	s->gu_ctl1		= I915_READ(VLV_GU_CTL1);
+	s->pcbr			= I915_READ(VLV_PCBR);
 	s->clock_gate_dis2	= I915_READ(VLV_GUNIT_CLOCK_GATE2);
 
 	/*
@@ -1165,6 +1166,7 @@ static void vlv_restore_gunit_s0ix_state(struct drm_i915_private *dev_priv)
 	/* Gunit-Display CZ domain, 0x182028-0x1821CF */
 	I915_WRITE(VLV_GU_CTL0,			s->gu_ctl0);
 	I915_WRITE(VLV_GU_CTL1,			s->gu_ctl1);
+	I915_WRITE(VLV_PCBR,			s->pcbr);
 	I915_WRITE(VLV_GUNIT_CLOCK_GATE2,	s->clock_gate_dis2);
 }
 
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 09501070d7cd..28c7afdfffbc 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -878,6 +878,7 @@ struct vlv_s0ix_state {
 	/* Display 2 CZ domain */
 	u32 gu_ctl0;
 	u32 gu_ctl1;
+	u32 pcbr;
 	u32 clock_gate_dis2;
 };
 
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