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Date: Tue, 08 Jan 2002 01:41:55 -0800
From: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
To: jamesclv@us.ibm.com, Marcelo Tosatti <marcelo@conectiva.com.br>
cc: linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@transmeta.com>
Subject: Re: [PATCH] MAX_MP_BUSSES increase
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> There's a problem with that -- despite its name, CONFIG_MULTIQUAD is used for 
> the old NUMA-Q hardware.  It turns on some memory mapped port I/O code that 
> doesn't have any purpose for other machines.  The PCI bus overflow happens on 
> our new Foster-based boxes that may or may not contain multiple quad CPU 
> boards.
> 
> Still, CONFIG_MULTIQUAD is better than nothing.  It just may take a little 
> bit of redefinition, so long as we can coax the various distros to build 
> their installation and working kernels with CONFIG_MULTIQUAD turned on....

That's not a good idea. You're going to introduce extra switches to every port
IO path, and every IPI (for everybody, not just yourself). CONFIG_MULTIQUAD 
is also used to alter the way that PCI config space writes are done (in later 
patches). I suggest you use a different config option, or construct it dynamically.

Martin.

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