lkml.org 
[lkml]   [2008]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: PCI MSI breaks when booting with nosmp
Date
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/

\
 
 \ /
  Last update: 2008-04-23 20:35    [W:0.037 / U:0.412 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site