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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
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Date: Thu, 08 May 2014 22:00:14 +0200
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Subject: Re: [Ksummit-discuss] [CORE TOPIC] Device error handling /
	reporting / isolation
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On Thursday, May 08, 2014 12:03:39 PM Bjorn Helgaas wrote:
> On Thu, May 8, 2014 at 6:37 AM, David Woodhouse <dwmw2@infradead.org>=
 wrote:
> > I'd like to have a discussion about handling device errors.
> >
> > IOMMUs are becoming more common, and we've seen some failure modes =
where
> > we just end up with an endless stream of fault reports from a given=

> > device, and the kernel can do nothing else.
> >
> > We may have various options for shutting it up =E2=80=94 a PCI func=
tion level
> > reset, power cycling the offending device, or maybe just configurin=
g the
> > IOMMU to *ignore* further errors from it, which would at least let =
the
> > system get on with doing something useful (and if we do, when do we=

> > re-enable reporting?).
> >
> > But I absolutely don't want us to be implementing policies like tha=
t in
> > an individual IOMMU driver; this needs to be handled by generic dev=
ice
> > code. Once upon a time I might have said PCI code, but this is actu=
ally
> > relevant for non-PCI devices too.
> >
> > I want the IOMMU to report errors, and let the system do the approp=
riate
> > thing. Which requires some discussion about what the "appropriate t=
hing"
> > can be in various circumstances, and indeed what options are availa=
ble
> > to us on various platforms.
>=20
> I'm interested in this discussion, too.

Yes, me too.

--=20
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.