Re: [PATCH 3/14] kexec: apic-virtwire-on-shutdown.i386.patch

[ebiederm@xmission.com (Eric W. Biederman)]

"Maciej W. Rozycki" <macro@linux-mips.org> writes:

> On Thu, 25 Aug 2004, Eric W. Biederman wrote:
> 
> > I don't think the configuration you are worrying about where
> > both the ioapic and the local apic can both be put into virtual
> > wire mode is valid according to the mp specification.  Although that
> > is probably a grey area in the specification.
> 
>  The spec doesn't preclude a configuration where the master i8259A is
> wired both to an I/O APIC input and to local APIC inputs.  If this is the
> case, it's a sole discretion of the system manufacturer to choose which
> route for the "virtual wire" is used.
> 
>  I don't insist on doing exact LVT restoration as at this stage it
> shouldn't really matter and the firmware should reinitialize the APIC
> subsystem completely anyway.  I just wanted to be sure you are aware of
> the issue.

Thanks. I will keep it in mind.

Actually now that I think about it I believe recent Intel chipsets
Tumwater/Lindenhurst work both ways but they have a bug that can
be triggered unless you are using the IOAPIC in virtual wire
mode.

In practice I still don't think it matters as everything across the
hub interface and PCI-e is message based and I don't think 2 messages
are generated.  Still I will give it some thought.

Eric