[PATCH] Support for PCI Express reset type in EEH

[Linas Vepstas]

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.

--linas

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