Re: PCI MSI breaks when booting with nosmp

From: Maciej W. Rozycki
Date: Wed Apr 23 2008 - 14:39:30 EST


On Wed, 23 Apr 2008, Jesse Barnes wrote:

> Yeah, I'm not particularly attached to either meaning. It looks like we'll
> setup the local apic on 32 bit if the NMI vector is a local apic one, so in
> that case at least the behavior will be the same.

Well, I did not follow changes to the code over the years and I think
enabling the local APIC for the NMI watchdog does not fit the semantics of
"nosmp" very well either. If you want the watchdog, then you can use
"maxcpus=1" or "maxcpus=1 noapic".

> Anyway, we have two options:
> 1) make nosmp/maxcpus=1 imply nolapic (and therefore disable MSI too)
> 2) make nosmp enable the lapic (so MSI will work)

Well, I have a slight affinity towards the first one (with "maxcpus=0"
that is; I'm assuming it's a typo above), but I do not think that is
something to be fiercely fought either.

MAciej
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