[PATCH] Support for PCI Express reset type in EEH

[Linas Vepstas]

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 ?

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.

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

--linas