[Intel-gfx] [PATCH 2/9] drm/i915: Write the FDI RX TU size reg at the right time

[Daniel Vetter]

According to "Graphics BSpec: vol4g North Display Engine Registers [IVB],
Display Mode Set Sequence" We need to write the TU size register
of the fdi RX unit _before_ starting to train the link.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_display.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0261d18..6cc9cb9 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2681,9 +2681,6 @@ static void ironlake_fdi_pll_enable(struct intel_crtc *intel_crtc)
 	int pipe = intel_crtc->pipe;
 	u32 reg, temp;
 
-	/* Write the TU size bits so error detection works */
-	I915_WRITE(FDI_RX_TUSIZE1(pipe),
-		   I915_READ(PIPE_DATA_M1(pipe)) & TU_SIZE_MASK);
 
 	/* enable PCH FDI RX PLL, wait warmup plus DMI latency */
 	reg = FDI_RX_CTL(pipe);
@@ -2996,6 +2993,11 @@ static void ironlake_pch_enable(struct drm_crtc *crtc)
 
 	assert_transcoder_disabled(dev_priv, pipe);
 
+	/* Write the TU size bits before fdi link training, so that error
+	 * detection works. */
+	I915_WRITE(FDI_RX_TUSIZE1(pipe),
+		   I915_READ(PIPE_DATA_M1(pipe)) & TU_SIZE_MASK);
+
 	/* For PCH output, training FDI link */
 	dev_priv->display.fdi_link_train(crtc);
 
-- 
1.7.11.4