[Intel-gfx] [PATCH] drm/i915/pch: Cosmetic fix to FDI link training

[Adam Jackson]

Unmask the bits for link training reporting before starting link
training.  If stage 1 training finished before we unmask them, then we'd
spin around in a loop a few times until smashing on through.  Which is
harmless, since training _did_ succeed, it just looks ugly in dmesg.

Signed-off-by: Adam Jackson <ajax at redhat.com>
---
 drivers/gpu/drm/i915/intel_display.c |   58 ++++++++++++++--------------------
 1 files changed, 24 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 88a1ab7..264881a 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1539,6 +1539,15 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 	int fdi_rx_imr_reg = (pipe == 0) ? FDI_RXA_IMR : FDI_RXB_IMR;
 	u32 temp, tries = 0;
 
+	/* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
+	   for train result */
+	temp = I915_READ(fdi_rx_imr_reg);
+	temp &= ~FDI_RX_SYMBOL_LOCK;
+	temp &= ~FDI_RX_BIT_LOCK;
+	I915_WRITE(fdi_rx_imr_reg, temp);
+	I915_READ(fdi_rx_imr_reg);
+	udelay(150);
+
 	/* enable CPU FDI TX and PCH FDI RX */
 	temp = I915_READ(fdi_tx_reg);
 	temp |= FDI_TX_ENABLE;
@@ -1556,16 +1565,7 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 	I915_READ(fdi_rx_reg);
 	udelay(150);
 
-	/* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
-	   for train result */
-	temp = I915_READ(fdi_rx_imr_reg);
-	temp &= ~FDI_RX_SYMBOL_LOCK;
-	temp &= ~FDI_RX_BIT_LOCK;
-	I915_WRITE(fdi_rx_imr_reg, temp);
-	I915_READ(fdi_rx_imr_reg);
-	udelay(150);
-
-	for (;;) {
+	for (tries = 0; tries < 5; tries++) {
 		temp = I915_READ(fdi_rx_iir_reg);
 		DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
 
@@ -1575,14 +1575,9 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 				   temp | FDI_RX_BIT_LOCK);
 			break;
 		}
-
-		tries++;
-
-		if (tries > 5) {
-			DRM_DEBUG_KMS("FDI train 1 fail!\n");
-			break;
-		}
 	}
+	if (tries == 5)
+		DRM_DEBUG_KMS("FDI train 1 fail!\n");
 
 	/* Train 2 */
 	temp = I915_READ(fdi_tx_reg);
@@ -1598,7 +1593,7 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 
 	tries = 0;
 
-	for (;;) {
+	for (tries = 0; tries < 5; tries++) {
 		temp = I915_READ(fdi_rx_iir_reg);
 		DRM_DEBUG_KMS("FDI_RX_IIR 0x%x\n", temp);
 
@@ -1608,14 +1603,9 @@ static void ironlake_fdi_link_train(struct drm_crtc *crtc)
 			DRM_DEBUG_KMS("FDI train 2 done.\n");
 			break;
 		}
-
-		tries++;
-
-		if (tries > 5) {
-			DRM_DEBUG_KMS("FDI train 2 fail!\n");
-			break;
-		}
 	}
+	if (tries == 5)
+		DRM_DEBUG_KMS("FDI train 2 fail!\n");
 
 	DRM_DEBUG_KMS("FDI train done\n");
 }
@@ -1640,6 +1630,15 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc)
 	int fdi_rx_imr_reg = (pipe == 0) ? FDI_RXA_IMR : FDI_RXB_IMR;
 	u32 temp, i;
 
+	/* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
+	   for train result */
+	temp = I915_READ(fdi_rx_imr_reg);
+	temp &= ~FDI_RX_SYMBOL_LOCK;
+	temp &= ~FDI_RX_BIT_LOCK;
+	I915_WRITE(fdi_rx_imr_reg, temp);
+	I915_READ(fdi_rx_imr_reg);
+	udelay(150);
+
 	/* enable CPU FDI TX and PCH FDI RX */
 	temp = I915_READ(fdi_tx_reg);
 	temp |= FDI_TX_ENABLE;
@@ -1665,15 +1664,6 @@ static void gen6_fdi_link_train(struct drm_crtc *crtc)
 	I915_READ(fdi_rx_reg);
 	udelay(150);
 
-	/* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
-	   for train result */
-	temp = I915_READ(fdi_rx_imr_reg);
-	temp &= ~FDI_RX_SYMBOL_LOCK;
-	temp &= ~FDI_RX_BIT_LOCK;
-	I915_WRITE(fdi_rx_imr_reg, temp);
-	I915_READ(fdi_rx_imr_reg);
-	udelay(150);
-
 	for (i = 0; i < 4; i++ ) {
 		temp = I915_READ(fdi_tx_reg);
 		temp &= ~FDI_LINK_TRAIN_VOL_EMP_MASK;
-- 
1.7.0.1