[PATCH] Support for PCI Express reset type in EEH

[Richard Lary]

Linas Vepstas <linasvepstas at gmail.com> wrote on 07/24/2009 05:30:09 PM:

> 2009/7/24 Richard Lary <rlary at us.ibm.com>:
> > Linas Vepstas <linasvepstas at gmail.com> wrote on 07/23/2009 07:44:33 AM:
> >
> >> 2009/7/15 Mike Mason <mmlnx at us.ibm.com>:
> >> > By default, EEH does what's known as a "hot reset" during error
recovery
> >> > of
> >> > a PCI Express device.  We've found a case where the device needs a
> >> > "fundamental reset" to recover properly.  The current PCI error
recovery
> >> > and
> >> > EEH frameworks do not support this distinction.
> >> >
> >> > The attached patch (courtesy of Richard Lary) adds a bit field to
> >> > pci_dev
> >> > that indicates whether the device requires a fundamental reset
during
> >> > error
> >> > recovery.  This bit can be checked by EEH to determine which reset
type
> >> > is
> >> > required.
> >> >
> >> > This patch supersedes the previously submitted patch that
implemented a
> >> > reset type callback.
> >> >
> >> > Please review and let me know of any concerns.
> >>
> >> I like this patch a *lot* better .. it is vastly simpler, more direct.
> >>
> >>
> >> > diff -uNrp a/include/linux/pci.h b/include/linux/pci.h
> >> > --- a/include/linux/pci.h       2009-07-13 14:25:37.000000000 -0700
> >> > +++ b/include/linux/pci.h       2009-07-15 10:25:37.000000000 -0700
> >> > @@ -273,6 +273,7 @@ struct pci_dev {
> >> >        unsigned int    ari_enabled:1;  /* ARI forwarding */
> >> >        unsigned int    is_managed:1;
> >> >        unsigned int    is_pcie:1;
> >> > +       unsigned int    fndmntl_rst_rqd:1; /* Dev requires
fundamental
> >> > reset
> >> > */
> >> >        unsigned int    state_saved:1;
> >> >        unsigned int    is_physfn:1;
> >> >        unsigned int    is_virtfn:1;
> >>
> >> As Ben points out, the name is awkward.  How about needs_freset ?
> >
> > I am OK with name change.
> >
> >
> >> Since this affects the entire pci subsystem, it should be documented
> >> properly.  The "pci error recovery" subsystem was designed to be
> >> usable in other architectures, and so the error recovery docs should
> >> take at least a paragraph to describe what this flag means, and when
> >> its supposed to be used.
> >
> > I will update the documentation, are you referring to
> > Documentation/powerpc/eeh-pci-error-recovery.txt
> > or some other documentation?
>
> No, I'm thinking
> Documentation/PCI/pci-error-recovery.txt
>
> because the flag is not powerpc-specific.

Got it, glad I asked...

-rich

> >
> >> Providing the docs patch together with the pci.h patch *only* would
> >> probably simplify acceptance by the PCI community.
> >>
> >> --linas
> >
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