[PATCH 2/8] drm/i915: don't disable/reenable IVB error interrupts when not needed

[Paulo Zanoni <przanoni@gmail.com>]

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

If the error interrupts are already disabled, don't disable and
reenable them. This is going to be needed when we're in PC8+, where
all the interrupts are disabled so we won't risk re-enabling
DE_ERR_INT_IVB.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6a1c207..2b0690a 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1309,6 +1309,7 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
 	drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
 	u32 de_iir, gt_iir, de_ier, sde_ier = 0;
 	irqreturn_t ret = IRQ_NONE;
+	bool err_int_reenable = false;
 
 	atomic_inc(&dev_priv->irq_received);
 
@@ -1337,7 +1338,10 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
 	 * handler. */
 	if (IS_HASWELL(dev)) {
 		spin_lock(&dev_priv->irq_lock);
-		ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);
+		if (!(I915_READ(DEIMR) & DE_ERR_INT_IVB)) {
+			ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);
+			err_int_reenable = true;
+		}
 		spin_unlock(&dev_priv->irq_lock);
 	}
 
@@ -1373,7 +1377,7 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
 		}
 	}
 
-	if (IS_HASWELL(dev)) {
+	if (err_int_reenable) {
 		spin_lock(&dev_priv->irq_lock);
 		if (ivb_can_enable_err_int(dev))
 			ironlake_enable_display_irq(dev_priv, DE_ERR_INT_IVB);
-- 
1.8.1.2