drm/i915: don't update GEN6_PMIMR when it's not needed
I did some brief tests and the "new_val = pmimr" condition usually
happens a few times after exiting games.
Note: This is also prep work to track the GEN6_PMIMR register state in
dev_priv->pm_imr. This happens in the next patch.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
[danvet: Add note to explain why we want this, as per the discussion
between Chris and Paulo.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index af5c335..efe3fc6 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -142,14 +142,18 @@
uint32_t interrupt_mask,
uint32_t enabled_irq_mask)
{
- uint32_t pmimr = I915_READ(GEN6_PMIMR);
- pmimr &= ~interrupt_mask;
- pmimr |= (~enabled_irq_mask & interrupt_mask);
+ uint32_t pmimr, new_val;
assert_spin_locked(&dev_priv->irq_lock);
- I915_WRITE(GEN6_PMIMR, pmimr);
- POSTING_READ(GEN6_PMIMR);
+ pmimr = new_val = I915_READ(GEN6_PMIMR);
+ new_val &= ~interrupt_mask;
+ new_val |= (~enabled_irq_mask & interrupt_mask);
+
+ if (new_val != pmimr) {
+ I915_WRITE(GEN6_PMIMR, new_val);
+ POSTING_READ(GEN6_PMIMR);
+ }
}
void snb_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)