From mboxrd@z Thu Jan  1 00:00:00 1970
From: Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [PATCH 45/53] drm/i915/bdw: Do not call
 intel_runtime_pm_get() in an interrupt
Date: Tue, 29 Jul 2014 08:37:48 +0100
Message-ID: <20140729073748.GD21570@nuc-i3427.alporthouse.com>
References: <1402673891-14618-1-git-send-email-oscar.mateo@intel.com>
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To: Daniel Vetter <daniel@ffwll.ch>
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On Mon, Jul 28, 2014 at 10:54:06AM +0200, Daniel Vetter wrote:
> On Sat, Jul 26, 2014 at 11:27:38AM +0100, Chris Wilson wrote:
> > On Wed, Jun 18, 2014 at 10:54:13PM +0200, Daniel Vetter wrote:
> > > On Fri, Jun 13, 2014 at 04:38:03PM +0100, oscar.mateo@intel.com wrote:
> > > > From: Oscar Mateo <oscar.mateo@intel.com>
> > > > 
> > > > Or with a spinlock grabbed, because it might sleep, which is not
> > > > a nice thing to do. Instead, do the runtime_pm get/put together
> > > > with the create/destroy request, and handle the forcewake get/put
> > > > directly.
> > > > 
> > > > Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
> > > 
> > > Looks like a fixup that should be squashed into relevant earlier patches.
> > 
> > The whole gen6_gt_force_wake_get() calling intel_runtime_pm_get() is
> > broken due to this - we must be able to read registers in atomic
> > context!
> > 
> > Please revert c8c8fb33b37766acf6474784b0d5245dab9a1690
> 
> force_wake_get can't call runtime_pm_get becuase pm_get can sleep. So if
> you want to read registers from atomic context you have to have a runtime
> pm reference from someone else.

Nope. That cannot work.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre