drm/i915/pch: Cosmetic fix to FDI link training

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@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

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 7e57eaba5e25..f67c74a25264 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1604,6 +1604,15 @@ 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;
@@ -1621,16 +1630,7 @@ 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);
 
@@ -1640,14 +1640,9 @@ 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);
@@ -1663,7 +1658,7 @@ 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);
 
@@ -1673,14 +1668,9 @@ 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");
 }
@@ -1705,6 +1695,15 @@ 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;
@@ -1730,15 +1729,6 @@ 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;