From: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
Date: Tue, 3 Apr 2007 08:21:41 +0000 (+0200)
Subject: Make sure we ack irqs before we read a breadcrumb so that
X-Git-Tag: android-x86-1.6~637
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=139e4bbc73c65d6e1d7fc831ae15c8b28f92e821;p=android-x86%2Fexternal-libdrm.git

Make sure we ack irqs before we read a breadcrumb so that

breadcrumb updates that occur _AFTER_ we've read the breadcrumb really
generates a new IRQ.
---

diff --git a/shared-core/i915_irq.c b/shared-core/i915_irq.c
index 5da54107..4047e77e 100644
--- a/shared-core/i915_irq.c
+++ b/shared-core/i915_irq.c
@@ -294,6 +294,8 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
 		return IRQ_NONE;
 
 	I915_WRITE16(I915REG_INT_IDENTITY_R, temp);
+	(void) I915_READ16(I915REG_INT_IDENTITY_R);
+	DRM_READMEMORYBARRIER();
 
 	dev_priv->sarea_priv->last_dispatch = READ_BREADCRUMB(dev_priv);