From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH] drm/i915: WARN if interrupts aren't on in
 en/disable_pipestat
Date: Wed, 27 Aug 2014 12:23:47 +0200
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To: Chris Wilson <chris@chris-wilson.co.uk>, Daniel Vetter <daniel.vetter@ffwll.ch>, Intel Graphics Development <intel-gfx@lists.freedesktop.org>, Paulo Zanoni <paulo.r.zanoni@intel.com>
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On Wed, Aug 27, 2014 at 09:51:58AM +0100, Chris Wilson wrote:
> On Wed, Aug 27, 2014 at 10:43:37AM +0200, Daniel Vetter wrote:
> > Now that vlv has runtime pm we kinda should check for that like on the
> > pch split platforms. Looks like this was simply lost in the vlv rpm
> > enabling.
> 
> Is there a reason why setting up the pipestat prior to enabling
> interrupts is verboten, or is it just not done today?

The similar warning on pch platforms was added to catch runtime pm bugs
where someone enabled some interrupt source, but didn't hold a runtime pm
reference. That's just not going to work. So motivation for this patch is
vlv/chv runtime pm really.

But I also think that this check provides value for driver
load/resume/suspend since if we change interrupt settings after the
interrupts have been disabled or before enabling something is at least
fishy. At least insofar as that our irq install hooks nowadays overwrite
all of them with default values.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch