This is a note to let you know that I've just added the patch titled
drm/i915: Avoid a double-read of PCH_IIR during interrupt handling
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-avoid-a-double-read-of-pch_iir-during-interrupt-handling.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 9adab8b5a7fde248504f484e197589f3e3c922e2 Mon Sep 17 00:00:00 2001
From: Chris Wilson <[email protected]>
Date: Wed, 9 May 2012 21:45:43 +0100
Subject: drm/i915: Avoid a double-read of PCH_IIR during interrupt handling
From: Chris Wilson <[email protected]>
commit 9adab8b5a7fde248504f484e197589f3e3c922e2 upstream.
Currently the code re-reads PCH_IIR during the hotplug interrupt
processing. Not only is this a wasted read, but introduces a potential
for handling a spurious interrupt as we then may not clear all the
interrupts processed (since the re-read IIR may contains more interrupts
asserted than we clear using the result of the original read).
Signed-off-by: Chris Wilson <[email protected]>
Cc: Jesse Barnes <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/i915/i915_irq.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -424,14 +424,11 @@ static void gen6_pm_rps_work(struct work
mutex_unlock(&dev_priv->dev->struct_mutex);
}
-static void pch_irq_handler(struct drm_device *dev)
+static void pch_irq_handler(struct drm_device *dev, u32 pch_iir)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
- u32 pch_iir;
int pipe;
- pch_iir = I915_READ(SDEIIR);
-
if (pch_iir & SDE_AUDIO_POWER_MASK)
DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
(pch_iir & SDE_AUDIO_POWER_MASK) >>
@@ -529,7 +526,7 @@ static irqreturn_t ivybridge_irq_handler
if (de_iir & DE_PCH_EVENT_IVB) {
if (pch_iir & SDE_HOTPLUG_MASK_CPT)
queue_work(dev_priv->wq, &dev_priv->hotplug_work);
- pch_irq_handler(dev);
+ pch_irq_handler(dev, pch_iir);
}
if (pm_iir & GEN6_PM_DEFERRED_EVENTS) {
@@ -629,7 +626,7 @@ static irqreturn_t ironlake_irq_handler(
if (de_iir & DE_PCH_EVENT) {
if (pch_iir & hotplug_mask)
queue_work(dev_priv->wq, &dev_priv->hotplug_work);
- pch_irq_handler(dev);
+ pch_irq_handler(dev, pch_iir);
}
if (de_iir & DE_PCU_EVENT) {
Patches currently in stable-queue which might be from [email protected]
are
queue-3.4/drm-i915-avoid-a-double-read-of-pch_iir-during-interrupt-handling.patch
--
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