[Intel-gfx] i915 irq storm mitigation in 3.10

[Egbert Eich]

Hi Jan!

Jan Niggemann writes:
 > Hi Egbert,

[...]

Thanks for generating the logs! Hope you had a nice birthday dinner :)

 > 
 > I applied this patch (but not the one you sent on Monday), recompiled 
 > and logged:
 > uncompressed (8,2M) http://files.hz6.de/kern_20130724.log
 > bz2 (288 KB) http://files.hz6.de/kern_20130724.log.bz2

These logs show clearly that we are seeing interrupts which
should be disabled.
Could it be that we we have either the status or enable bits
mixed up? Unfortunately the publically available docs for GEN4
don't show the HOTPLUG_EN and HOTPLUG_STAT registers.

Daniel, could you please help me out here?

Thanks a lot!

Cheers,
	Egbert.