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Re: PCI MSI breaks when booting with nosmp

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From: Maciej W. Rozycki
Subject: Re: PCI MSI breaks when booting with nosmp
Date: Wednesday, April 23, 2008 - 11:13 am

On Wed, 23 Apr 2008, Jesse Barnes wrote:


 FWIW, the original idea behind "nosmp" or "maxcpus=0" (just as an
implementation detail) vs "maxcpus=1" was that the two formers would
disable the APIC circuitry altogether (including resisting from switching
from the PIC compatibility mode on systems supporting it), while the
latter would still boot UP, but with interrupts routed through the APICs.  
Essentially SMP implied all the MP circuitry/provisions in this context,
the APICs being an inherent part of which.  Therefore I think the original
idea of implying "pci=nomsi" with "nosmp" certainly looks more in the
spirit of the original setup to me.

 However we have "nolapic" these days as well and with this new proposal
this option could effectively take over the old meaning of "nosmp" (you
cannot do SMP without the local APIC, so "nolapic nosmp" is redundant).  
I am not entirely convinced it is the right way though...

  Maciej
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Messages in current thread:
PCI MSI breaks when booting with nosmp, Jean Delvare, (Thu Apr 17, 12:40 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Thu Apr 17, 1:08 pm)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Thu Apr 17, 1:25 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Mon Apr 21, 10:43 am)
Re: PCI MSI breaks when booting with nosmp, Andi Kleen, (Mon Apr 21, 11:45 am)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Mon Apr 21, 12:06 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Mon Apr 21, 12:35 pm)
Re: PCI MSI breaks when booting with nosmp, Andi Kleen, (Mon Apr 21, 12:41 pm)
Re: PCI MSI breaks when booting with nosmp, Pavel Machek, (Mon Apr 21, 12:43 pm)
Re: PCI MSI breaks when booting with nosmp, Andi Kleen, (Mon Apr 21, 12:44 pm)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Mon Apr 21, 1:20 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Mon Apr 21, 1:40 pm)
Re: PCI MSI breaks when booting with nosmp, Andi Kleen, (Mon Apr 21, 1:46 pm)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Mon Apr 21, 1:48 pm)
Re: PCI MSI breaks when booting with nosmp, Andi Kleen, (Mon Apr 21, 2:09 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Mon Apr 21, 2:14 pm)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Tue Apr 22, 6:27 am)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Tue Apr 22, 8:50 am)
Re: PCI MSI breaks when booting with nosmp, Pavel Machek, (Tue Apr 22, 2:25 pm)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Tue Apr 22, 4:07 pm)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Wed Apr 23, 7:38 am)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Wed Apr 23, 8:12 am)
Re: PCI MSI breaks when booting with nosmp, Maciej W. Rozycki, (Wed Apr 23, 11:13 am)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Wed Apr 23, 11:23 am)
Re: PCI MSI breaks when booting with nosmp, Jesse Barnes, (Wed Apr 23, 11:32 am)
Re: PCI MSI breaks when booting with nosmp, Jean Delvare, (Wed Apr 23, 11:32 am)
Re: PCI MSI breaks when booting with nosmp, Maciej W. Rozycki, (Wed Apr 23, 11:38 am)