[RFC/PATCH 14/16] MPIC MSI backend

[Michael Ellerman]

On Fri, 2007-01-26 at 10:56 -0700, Eric W. Biederman wrote:
> Grant Grundler <grundler at parisc-linux.org> writes:
> > Helping Michael make it work would be a constructive way forward.
> > I think Michael has the abstraction correct so it's NOT x86 centric
> > but still works optimally on x86.
> 
> NO NO NO NO Michaels abstraction does not work on x86.
> Which is a big part of the my problem.
> Michaels abstraction does not allow me to migrate irqs on x86.
> 
> setup_msi_msg only gets called when you enable the msi.  Nothing
> gets called when irqbalaced changes the cpu mask, and there is no
> support that would allow that with Michael's msi ops.

That's all part of the backend. You just give me an irq_desc attached to
a chip with set_affinity = set_msi_irq_affinity, exactly like the
current code.

> That is why I have asked for an evolutionary approach and not this
> stupid drop and replace attempt.

I don't intend to drop and replace, I agree that's stupid. My hope was
to have the two implementations coexist for a kernel release, giving us
time to find all the bugs on PowerPC - where we have lots fewer MSI
users to piss off - and then port Intel over.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
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