From d4599f3bbffe162f91ebeea6c610af549a34348b Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 9 May 2012 21:45:43 +0100 Subject: [PATCH] drm/i915: Avoid a double-read of PCH_IIR during interrupt handling 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 Cc: Jesse Barnes Signed-off-by: Daniel Vetter Signed-off-by: Ben Hutchings --- drivers/gpu/drm/i915/i915_irq.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index d47a53b1db84..d3820c2a98aa 100644 --- 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_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(DRM_IRQ_ARGS) 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(DRM_IRQ_ARGS) 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) { -- 2.39.2