Re: Re: [PATCH] Handle disabled local apic better

[Len Brown <len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

> BTW if that is all cleaned up I would suggest just to get rid of the CONFIGs
> and always use runtime defaults. This would make these parts more maintainable
> I think and is the right thing to do for distributions.

tempting.
I gues if nobody builds with !CONFIG_X86_LOCAL_APIC anyway, then
run-time check is the way to go.


> > Here we're disabling MPS with "nolapic" -- something that "maxcpus=0"
> > and "nosmp" never effectively did before...
> 
> MPS without local APIC is useless.

I agree, my point is that "nosmp" and "maxcpus=0" are broken in that
they didn't disable MPS this early.


> > >  /*
> > >   * This initializes the IO-APIC and APIC hardware if this is
> > > @@ -1009,12 +1010,14 @@
> > >  
> > >  static __init int setup_disableapic(char *str) 
> > >  { 
> > > +	enable_local_apic = -1;
> > >  	disable_apic = 1;
> > >  	return 0;
> > >  } 
> > >  
> > >  static __init int setup_nolapic(char *str) 
> > >  { 
> > > +	enable_local_apic = -1;
> > >  	disable_apic = 1;
> > >  	return 0;
> > >  } 
> > 
> > these routines should be deleted, since they duplicate the earlier
> > parse_cmdline_early().  the ambiguous "disable_lapic" should go also,
> > since "enable_local_apic" is on the scene, yes?
> 
> No, even when you parse in parse_cmdline_early() you need a __setup,
> otherwise the normal __setup parser will complain about unknown 
> options.

Huh?  So if I boot a kernel with an unknown parameter, say
"len=gone_fishing", where would I expect to see the complaint -- I don't
see it in my dmesg except where the entire commmand line is dumped out.

thanks,
-Len




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