Re: [PATCH 02/21] drm/i915: Shut down PCH interrupts duringirq_uninstall

From: Daniel Vetter
Date: Fri Sep 30 2011 - 13:55:41 EST


On Fri, Sep 30, 2011 at 10:44:22AM -0700, Keith Packard wrote:
> On Fri, 30 Sep 2011 18:20:48 +0200, Daniel Vetter <daniel@xxxxxxxx> wrote:
>
> > Shouldn't we mask/ack south DE irqs before before we mask DE irqs to avoid
> > races, i.e. move this new code up?
>
> I don't know. What about the GT interrupts? I just stuck stuff at the
> bottom, figuring it would do the least harm...

Thinking this through again I don't see the race anymore. I've forgotten
that masking things in IMR also prevents stuff from showing up in IIR and
hence a SDE irq after clearing DE irqs can't leave garbage behind in
DEIIR. So no need to clear things in the order the irqs propagate, i.e.
SDE->DE->GT. For the patch:

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
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Daniel Vetter
Mail: daniel@xxxxxxxx
Mobile: +41 (0)79 365 57 48
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