[Intel-gfx] Patch for testing irq spinning

Keith Packard keithp at keithp.com
Fri Dec 5 01:54:00 CET 2008


On Thu, 2008-12-04 at 15:43 +0100, Tomas Carnecky wrote:

> Should I apply both patches or only the second one (the one that adds 
> the 'break;')? I applied both and I was still getting the IRQ storms. 
> This is also on a GM965.

It shouldn't have mattered. At this point, I'm curious if we're running
into trouble because of interrupt sharing. We've had good reports from
people using MSI on GM965, notwithstanding the errata which says they're
unreliable. It may be that our driver/linux uses them differently enough
that they work fine. Here's a patch which re-enables MSI for 965GM. Use
this in place of the other two patches and let us know if it works. In
other words, revert back to anholt/for-airlied and apply this patch:

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index ba89b42..553dd4b 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -847,9 +847,10 @@ int i915_driver_load(struct drm_device *dev, unsigned long 
flags)
 	 * and the registers being closely associated.
 	 *
 	 * According to chipset errata, on the 965GM, MSI interrupts may
-	 * be lost or delayed
+	 * be lost or delayed, but we use them anyways to avoid
+	 * stuck interrupts on some machines.
 	 */
-	if (!IS_I945G(dev) && !IS_I945GM(dev) && !IS_I965GM(dev))
+	if (!IS_I945G(dev) && !IS_I945GM(dev))
 		pci_enable_msi(dev->pdev);
 
 	intel_opregion_init(dev);

-- 
keith.packard at intel.com
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