[PATCH 09/20] drm/i915: fix SERR_INT init/reset code

[Paulo Zanoni <przanoni@gmail.com>]

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

The SERR_INT register is very similar to the other IIR registers, so
let's zero it at preinstall/uninstall and WARN for a non-zero value at
postinstall, just like we do with the other IIR registers. For this
one, there's no need to double-clear since it can't store more than
one interrupt.

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 4d0a8b1..d295624 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2811,6 +2811,10 @@ static void ibx_irq_preinstall(struct drm_device *dev)
 		return;
 
 	GEN5_IRQ_RESET(SDE);
+
+	if (HAS_PCH_CPT(dev) || HAS_PCH_LPT(dev))
+		I915_WRITE(SERR_INT, 0xffffffff);
+
 	/*
 	 * SDEIER is also touched by the interrupt handler to work around missed
 	 * PCH interrupts. Hence we can't update it after the interrupt handler
@@ -2949,7 +2953,7 @@ static void ibx_irq_postinstall(struct drm_device *dev)
 	} else {
 		mask = SDE_GMBUS_CPT | SDE_AUX_MASK_CPT | SDE_ERROR_CPT;
 
-		I915_WRITE(SERR_INT, I915_READ(SERR_INT));
+		GEN5_ASSERT_IIR_IS_ZERO(SERR_INT);
 	}
 
 	GEN5_ASSERT_IIR_IS_ZERO(SDEIIR);
@@ -3303,7 +3307,7 @@ static void ironlake_irq_uninstall(struct drm_device *dev)
 
 	GEN5_IRQ_RESET(SDE);
 	if (HAS_PCH_CPT(dev) || HAS_PCH_LPT(dev))
-		I915_WRITE(SERR_INT, I915_READ(SERR_INT));
+		I915_WRITE(SERR_INT, 0xffffffff);
 }
 
 static void i8xx_irq_preinstall(struct drm_device * dev)
-- 
1.8.5.3