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Subject: Re: [PATCH 0/4] powerpc: Fix minor build issues on 2.6.32-rc7
	without CONFIG_XICS set
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Date: Wed, 18 Nov 2009 17:00:56 +1100
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Cc: Mel Gorman <mel@csn.ul.ie>, linuxppc-dev@ozlabs.org,
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On Tue, 2009-11-17 at 23:52 +1100, Michael Ellerman wrote:
> 
> In fact this series makes me wonder whether we can drop support for a
> single kernel image with pseries XICS & MPIC support.

Nope. Not happening. We should just hide CONFIG_XICS just like
CONFIG_MPIC, it should be select'ed by the platform (which today is only
pseries but that might change).

> If we could drop that requirement we could have a single set of names,
> ie. API, for the irq routines and build either the XICS or MPIC
> versions.

And so we would have the ability to build a kernel that supports in a
single binary every platform, as is the case today, ie, pseries,
powermac, pa6t, cell, etc... _BUT_ for pseries support, we would have to
choose at compile time whether to support old or new machines ? Sounds
backward to me :-)

> That would avoid all the code that needs a setup_foo_xics() and
> setup_foo_mpic() - it'd just be setup_foo(), implemented by either the
> XICS or MPIC code.

And that would save us what ? one page on a pSeries machine ? yeah !

Cheers,
Ben.