[Intel-gfx] [PATCH] drm/i915: make sure plane control reg changes take effect

[Jesse Barnes]

After writing to the plane control reg we need to write to the surface
reg to trigger the double buffered register latch.

Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 32ffde2..9fefba3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1333,6 +1333,8 @@ static void intel_disable_plane(struct drm_i915_private *dev_priv,
 		return;
 
 	I915_WRITE(reg, val & ~DISPLAY_PLANE_ENABLE);
+	/* Flush out the double buffered plane control reg */
+	I915_WRITE(DSPSURF(plane), I915_READ(DSPSURF(plane)));
 	intel_flush_display_plane(dev_priv, plane);
 	intel_wait_for_vblank(dev_priv->dev, pipe);
 }
-- 
1.7.4.1