From: Chris Wilson Date: Wed, 9 May 2012 20:45:43 +0000 (+0100) Subject: drm/i915: Avoid a double-read of PCH_IIR during interrupt handling X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9adab8b5a7fde248504f484e197589f3e3c922e2;p=linux-beck.git drm/i915: Avoid a double-read of PCH_IIR during interrupt handling 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 Cc: stable@kernel.org Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index b4999b5288e8..14943ba4d731 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -533,14 +533,11 @@ out: return ret; } -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) >> @@ -633,7 +630,7 @@ 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) @@ -721,7 +718,7 @@ 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) {