drm/i915: Fix KMS regression on Sandybridge/CPT

We should enable FDI normal training on Sandybridge/CPT system
as well.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
[ickle: removed unrelated chunks]
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 33 insertions, 21 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 528aa06d430d..5e839c762456 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1681,6 +1681,37 @@ static void ironlake_set_pll_edp(struct drm_crtc *crtc, int clock)
         udelay(500);
 }
 
+static void intel_fdi_normal_train(struct drm_crtc *crtc)
+{
+        struct drm_device *dev = crtc->dev;
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+        int pipe = intel_crtc->pipe;
+        u32 reg, temp;
+
+        /* enable normal train */
+        reg = FDI_TX_CTL(pipe);
+        temp = I915_READ(reg);
+        temp &= ~FDI_LINK_TRAIN_NONE;
+        temp |= FDI_LINK_TRAIN_NONE | FDI_TX_ENHANCE_FRAME_ENABLE;
+        I915_WRITE(reg, temp);
+
+        reg = FDI_RX_CTL(pipe);
+        temp = I915_READ(reg);
+        if (HAS_PCH_CPT(dev)) {
+                temp &= ~FDI_LINK_TRAIN_PATTERN_MASK_CPT;
+                temp |= FDI_LINK_TRAIN_NORMAL_CPT;
+        } else {
+                temp &= ~FDI_LINK_TRAIN_NONE;
+                temp |= FDI_LINK_TRAIN_NONE;
+        }
+        I915_WRITE(reg, temp | FDI_RX_ENHANCE_FRAME_ENABLE);
+
+        /* wait one idle pattern time */
+        POSTING_READ(reg);
+        udelay(1000);
+}
+
 /* The FDI link training functions for ILK/Ibexpeak. */
 static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 {
@@ -1767,27 +1798,6 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 
         DRM_DEBUG_KMS("FDI train done\n");
 
-        /* enable normal train */
-        reg = FDI_TX_CTL(pipe);
-        temp = I915_READ(reg);
-        temp &= ~FDI_LINK_TRAIN_NONE;
-        temp |= FDI_LINK_TRAIN_NONE | FDI_TX_ENHANCE_FRAME_ENABLE;
-        I915_WRITE(reg, temp);
-
-        reg = FDI_RX_CTL(pipe);
-        temp = I915_READ(reg);
-        if (HAS_PCH_CPT(dev)) {
-                temp &= ~FDI_LINK_TRAIN_PATTERN_MASK_CPT;
-                temp |= FDI_LINK_TRAIN_NORMAL_CPT;
-        } else {
-                temp &= ~FDI_LINK_TRAIN_NONE;
-                temp |= FDI_LINK_TRAIN_NONE;
-        }
-        I915_WRITE(reg, temp | FDI_RX_ENHANCE_FRAME_ENABLE);
-
-        /* wait one idle pattern time */
-        POSTING_READ(reg);
-        udelay(1000);
 }
 
 static const int const snb_b_fdi_train_param [] = {
@@ -2090,6 +2100,8 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
         I915_WRITE(TRANS_VBLANK(pipe), I915_READ(VBLANK(pipe)));
         I915_WRITE(TRANS_VSYNC(pipe),  I915_READ(VSYNC(pipe)));
 
+        intel_fdi_normal_train(crtc);
+
         /* For PCH DP, enable TRANS_DP_CTL */
         if (HAS_PCH_CPT(dev) &&
             intel_pipe_has_type(crtc, INTEL_OUTPUT_DISPLAYPORT)) {