[Intel-gfx] [PATCH 18/29] drm/i915/crt: Flush register prior to waiting for vblank.

[Chris Wilson]

If we don't flush the write then we can not be sure that the border
colour will have taken effect by the time we try to read it back.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_crt.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 4b77351..f915793 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -327,6 +327,7 @@ intel_crt_load_detect(struct drm_crtc *crtc, struct intel_encoder *intel_encoder
 	if (IS_I9XX(dev)) {
 		uint32_t pipeconf = I915_READ(pipeconf_reg);
 		I915_WRITE(pipeconf_reg, pipeconf | PIPECONF_FORCE_BORDER);
+		POSTING_READ(pipeconf_reg);
 		/* Wait for next Vblank to substitue
 		 * border color for Color info */
 		intel_wait_for_vblank(dev, pipe);
-- 
1.7.1