From efe7db1c227423bf920c9a49b4f99f1eaae97937 Mon Sep 17 00:00:00 2001
From: Vinit Azad <vinit.azad@intel.com>
Date: Wed, 14 Aug 2013 13:34:33 -0700
Subject: drm/i915: Only unmask required PM interrupts

Un-masking all PM interrupts causes hardware to generate
interrupts regardless of whether the interrupts are enabled
on the DE side. Since turbo only need up/down threshold and
rc6 timeout interrupt, mask all other interrupts bits to avoid
unnecessary overhead/wake up.

Note that our interrupt handler isn't being fired since we do set the
IER bits properly (IIR bits aren't set). The overhead isn't because
our driver is reacting to these interrupts, but because hardware keeps
generating internal messages when PMINTRMSK doesn't mask out the
up/down EI interrupts (which happen periodically).

Signed-off-by: Vinit Azad <vinit.azad@intel.com>
[danvet: Add follow-up explanation of the precise effects from Vinit
as a note to the commit message.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

(cherry picked from commit fd547d25a8ac3f390fee4a689de86a64e3d65fe1)
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d82d70588d11..21f4c958bbfe 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3453,8 +3453,8 @@ static void gen6_enable_rps_interrupts(struct drm_device *dev)
 	I915_WRITE(GEN6_PMIMR, I915_READ(GEN6_PMIMR) & ~GEN6_PM_RPS_EVENTS);
 	I915_WRITE(GEN6_PMIIR, GEN6_PM_RPS_EVENTS);
 	spin_unlock_irq(&dev_priv->irq_lock);
-	/* unmask all PM interrupts */
-	I915_WRITE(GEN6_PMINTRMSK, 0);
+	/* only unmask PM interrupts we need. Mask all others. */
+	I915_WRITE(GEN6_PMINTRMSK, ~GEN6_PM_RPS_EVENTS);
 }
 
 static void gen6_enable_rps(struct drm_device *dev)
-- 
1.8.5.rc3