drm/i915/suspend: Flush register writes before busy-waiting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 18 insertions, 9 deletions

diff --git a/drivers/gpu/drm/i915/i915_suspend.c b/drivers/gpu/drm/i915/i915_suspend.c
index 6e2025274db5..05acc26fabf7 100644
--- a/drivers/gpu/drm/i915/i915_suspend.c
+++ b/drivers/gpu/drm/i915/i915_suspend.c
@@ -395,16 +395,20 @@ static void i915_restore_modeset_reg(struct drm_device *dev)
         if (dev_priv->saveDPLL_A & DPLL_VCO_ENABLE) {
                 I915_WRITE(dpll_a_reg, dev_priv->saveDPLL_A &
                            ~DPLL_VCO_ENABLE);
-                DRM_UDELAY(150);
+                POSTING_READ(dpll_a_reg);
+                udelay(150);
         }
         I915_WRITE(fpa0_reg, dev_priv->saveFPA0);
         I915_WRITE(fpa1_reg, dev_priv->saveFPA1);
         /* Actually enable it */
         I915_WRITE(dpll_a_reg, dev_priv->saveDPLL_A);
-        DRM_UDELAY(150);
-        if (IS_I965G(dev) && !IS_IRONLAKE(dev))
+        POSTING_READ(dpll_a_reg);
+        udelay(150);
+        if (IS_I965G(dev) && !IS_IRONLAKE(dev)) {
                 I915_WRITE(DPLL_A_MD, dev_priv->saveDPLL_A_MD);
-        DRM_UDELAY(150);
+                POSTING_READ(DPLL_A_MD);
+        }
+        udelay(150);
 
         /* Restore mode */
         I915_WRITE(HTOTAL_A, dev_priv->saveHTOTAL_A);
@@ -460,16 +464,20 @@ static void i915_restore_modeset_reg(struct drm_device *dev)
         if (dev_priv->saveDPLL_B & DPLL_VCO_ENABLE) {
                 I915_WRITE(dpll_b_reg, dev_priv->saveDPLL_B &
                            ~DPLL_VCO_ENABLE);
-                DRM_UDELAY(150);
+                POSTING_READ(dpll_b_reg);
+                udelay(150);
         }
         I915_WRITE(fpb0_reg, dev_priv->saveFPB0);
         I915_WRITE(fpb1_reg, dev_priv->saveFPB1);
         /* Actually enable it */
         I915_WRITE(dpll_b_reg, dev_priv->saveDPLL_B);
-        DRM_UDELAY(150);
-        if (IS_I965G(dev) && !IS_IRONLAKE(dev))
+        POSTING_READ(dpll_b_reg);
+        udelay(150);
+        if (IS_I965G(dev) && !IS_IRONLAKE(dev)) {
                 I915_WRITE(DPLL_B_MD, dev_priv->saveDPLL_B_MD);
-        DRM_UDELAY(150);
+                POSTING_READ(DPLL_B_MD);
+        }
+        udelay(150);
 
         /* Restore mode */
         I915_WRITE(HTOTAL_B, dev_priv->saveHTOTAL_B);
@@ -730,7 +738,8 @@ void i915_restore_display(struct drm_device *dev)
         I915_WRITE(VGA0, dev_priv->saveVGA0);
         I915_WRITE(VGA1, dev_priv->saveVGA1);
         I915_WRITE(VGA_PD, dev_priv->saveVGA_PD);
-        DRM_UDELAY(150);
+        POSTING_READ(VGA_PD);
+        udelay(150);
 
         i915_restore_vga(dev);
 }