[Intel-gfx] [PATCH 6/6] drm/i915: don't save/restore HWS_PGA reg for kms

[Daniel Vetter]

We already do that as part of the ringbuffer re-setup at resume time.
Furthermore the register offset has moved on gen6+ around quite a bit,
and on ilk/gm45 we also need to restore the HWS reg for the bsd ring,
not just the render ring.

So again in kms mode this is only confusing a best, hence don't
bother.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_suspend.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 44893be..f9630d9 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -814,7 +814,8 @@ int i915_save_state(struct drm_device *dev)
 	mutex_lock(&dev->struct_mutex);
 
 	/* Hardware status page */
-	dev_priv->saveHWS = I915_READ(HWS_PGA);
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		dev_priv->saveHWS = I915_READ(HWS_PGA);
 
 	i915_save_display(dev);
 
@@ -867,7 +868,8 @@ int i915_restore_state(struct drm_device *dev)
 	mutex_lock(&dev->struct_mutex);
 
 	/* Hardware status page */
-	I915_WRITE(HWS_PGA, dev_priv->saveHWS);
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		I915_WRITE(HWS_PGA, dev_priv->saveHWS);
 
 	i915_restore_display(dev);
 
-- 
1.7.11.2