Messages in this thread | | | From | Jean Delvare <> | Subject | Re: PCI MSI breaks when booting with nosmp | Date | Wed, 23 Apr 2008 20:32:39 +0200 |
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Le mercredi 23 avril 2008, Jesse Barnes a écrit : > On Wednesday, April 23, 2008 11:13 am Maciej W. Rozycki wrote: > > On Wed, 23 Apr 2008, Jesse Barnes wrote: > > > Yeah I think the patch is reasonable, would be good to get feedback from > > > Thomas/Andi/Ingo though... > > > > 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... > > 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. > > 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)
No opinion. As long as I can boot with "nosmp" and things work, I'm happy.
-- Jean Delvare Suse L3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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