RE: [patch 1/1] Do not enforce unique IO_APIC_ID for Xeon processors in EM64T mode (x86_64)

["Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>]

> On Wed, May 11, 2005 at 11:21:15AM -0500, Protasevich, Natalie wrote:
> > > > Looks like the need in the unique id can only be keyed of the 
> > > > local APIC id, and probably it is a good idea to keep the 
> > > > NO_IOAPIC_CHECK for subarchs that can override the heuristics?
> > > 
> > > I prefer not to do that. How about a simple
> > > 
> > > if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
> > > boot_cpu_data.x86 < 15)
> > > 	/* do uniqueness check */
> > > else
> > > 	/* don't do it */
> > > 
> > > ?		
> > > 
> > > Rationale is that P4s and newer and systems not from Intel don't 
> > > have serial APIC busses and don't need this uniqueness check.
> > >
> > 
> > Yes, indeed this looks like the only undisputed (and sufficient) 
> > criteria. I tried the below with Xeon box and it worked fine:
> > 
> > --- mpparse.c.orig	2005-05-11 02:10:35.000000000 -0400
> > +++ mpparse.c	2005-05-11 02:12:31.000000000 -0400
> > @@ -912,7 +913,15 @@ void __init mp_register_ioapic (
> >  	mp_ioapics[idx].mpc_apicaddr = address;
> >  
> >  	set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
> > -	mp_ioapics[idx].mpc_apicid = io_apic_get_unique_id(idx, id);
> > +	if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
> > (boot_cpu_data.x86 >= 15))
> > +		mp_ioapics[idx].mpc_apicid = id;
> > +	else
> 
> That's still wrong because it does not trigger on AMD 
> systems. 

So no AMD systems need that check? OK, I'll change it as below.

> Please make it
> 
> 	if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && 
> boot_cpu_data.x86 < 15)
> 		mp_ioapics[idx].mpc_apicid = 
> io_apic_get_unique_id(idx,id);
> 	else
> 		mp_ioapics[idx].mpc_apicid = id;
> 
-
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