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Date:      Thu, 26 Sep 1996 07:31:34 -0700
From:      erich@uruk.org
To:        Peter Wemm <peter@spinner.dialix.com>, Poul-Henning Kamp <phk@critter.tfs.com>
Cc:        Dayton Clark <dayton@sci.brooklyn.cuny.edu>, freebsd-smp@freebsd.org
Subject:   Re: QuadPro Motherboard 
Message-ID:  <199609261431.HAA19077@uruk.org>
In-Reply-To: Your message of "Thu, 26 Sep 1996 15:44:57 %2B0800." <199609260744.PAA00409@spinner.DIALix.COM> 

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Peter Wemm <peter@spinner.dialix.com> writes:

> Poul-Henning Kamp wrote:
> > In message <199609252257.PAA16923@uruk.org>, erich@uruk.org writes:
> > >
> > >Dayton Clark <dayton@sci.brooklyn.cuny.edu> writes:
> > >
> > >> We've got an attractive quote on 4CPU systems with QuadPro
> > >> motherboards which use the Orion chipset.  I plan to try Freebsd-SMP
> > >> on one of them, at least for awhile.
> > >
> > >Uhh...  as far as I know, no P6 motherboard will work with FreeBSD-SMP.
> > 
> > it worked fine on the HP 2xP6/150 I tried it on...

Interesting!!!  All the Pentium Pro boxes I tried Linux on when I was
testing it had the local APIC at a different address than the default,
so the "#define" as it currently is simply failed to work.

Did you change the local APIC address?

> There is a tweakable #define in the current boot code that tells the 
> booting cpu the apic ID of the other cpu.  Normally, this is 1, but if the 
> boot cpu is #1 (or something else), then the boot cpu can start cpu #0 or 
> whatever.
> 
> It's not pretty but it should work enough to be usable.

Again, that's only part of it.  To get my big test box to work (it has
CPUs numbered 0, 1, 2, and 4, with the boot CPU as #0), the main thing
I had to do to get 2 CPUs running was change the local APIC address.

On all the Pentium Pro boxes I've tried, it was always 0xFEC08000
instead of the default 0xFEE0000.  NOTE that the I/O APIC defaults
to 0xFEC00000.  I think since you can relocate the local APIC, they
did that in many of the Pentium Pro designs to fragment the address
space as little as possible.

--
  Erich Stefan Boleyn                 \_ E-mail (preferred):  <erich@uruk.org>
Mad Genius wanna-be, CyberMuffin        \__      (finger me for other stats)
Web:  http://www.uruk.org/~erich/     Motto: "I'll live forever or die trying"



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