[Intel-gfx] [PATCH] drm/i915/tv: Flush register writes before sleeping.

[Chris Wilson]

If we need to wait until the next vblank for the register to be updated
and to take effect, make sure the write is actually flushed to the register
prior to sleeping.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_tv.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_tv.c b/drivers/gpu/drm/i915/intel_tv.c
index d2105f0..46fc3aa 100644
--- a/drivers/gpu/drm/i915/intel_tv.c
+++ b/drivers/gpu/drm/i915/intel_tv.c
@@ -1155,10 +1155,13 @@ intel_tv_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode,
 		I915_WRITE(dspbase_reg, I915_READ(dspbase_reg));
 
 		/* Wait for vblank for the disable to take effect */
-		if (!IS_I9XX(dev))
+		if (!IS_I9XX(dev)) {
+			POSTING_READ(dspbase_reg);
 			intel_wait_for_vblank(dev);
+		}
 
 		I915_WRITE(pipeconf_reg, pipeconf & ~PIPEACONF_ENABLE);
+		POSTING_READ(pipeconf_reg);
 		/* Wait for vblank for the disable to take effect. */
 		intel_wait_for_vblank(dev);
 
@@ -1267,11 +1270,15 @@ intel_tv_detect_type (struct intel_tv *intel_tv)
 		   DAC_C_0_7_V);
 	I915_WRITE(TV_CTL, tv_ctl);
 	I915_WRITE(TV_DAC, tv_dac);
+	POSTING_READ(TV_DAC);
 	intel_wait_for_vblank(dev);
+
 	tv_dac = I915_READ(TV_DAC);
 	I915_WRITE(TV_DAC, save_tv_dac);
 	I915_WRITE(TV_CTL, save_tv_ctl);
+	POSTING_READ(TV_CTL);
 	intel_wait_for_vblank(dev);
+
 	/*
 	 *  A B C
 	 *  0 1 1 Composite
-- 
1.7.1