[PATCH 06/21] drm/i915: Optimize gen8_enable|disable_vblank functions

[Ben Widawsky <benjamin.widawsky@intel.com>]

From: Daniel Vetter <daniel.vetter@ffwll.ch>

Let's cache the IMR value like on other platforms. This is needed to
implement the underrun reporting since then we'll have two places that
change the same register at runtime.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_irq.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index a06de99..9ea0df2 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2203,17 +2203,14 @@ static int gen8_enable_vblank(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
-	uint32_t imr;
 
 	if (!i915_pipe_enabled(dev, pipe))
 		return -EINVAL;
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
-	imr = I915_READ(GEN8_DE_PIPE_IMR(pipe));
-	if ((imr & GEN8_PIPE_VBLANK) == 1) {
-		I915_WRITE(GEN8_DE_PIPE_IMR(pipe), imr & ~GEN8_PIPE_VBLANK);
-		POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
-	}
+	dev_priv->de_irq_mask[pipe] &= ~GEN8_PIPE_VBLANK;
+	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);
+	POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 	return 0;
 }
@@ -2270,17 +2267,14 @@ static void gen8_disable_vblank(struct drm_device *dev, int pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;
-	uint32_t imr;
 
 	if (!i915_pipe_enabled(dev, pipe))
 		return;
 
 	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
-	imr = I915_READ(GEN8_DE_PIPE_IMR(pipe));
-	if ((imr & GEN8_PIPE_VBLANK) == 0) {
-		I915_WRITE(GEN8_DE_PIPE_IMR(pipe), imr | GEN8_PIPE_VBLANK);
-		POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
-	}
+	dev_priv->de_irq_mask[pipe] |= GEN8_PIPE_VBLANK;
+	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);
+	POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
 	spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 }
 
-- 
1.8.4.2