Re: UP local APIC is deadly on SMP Athlon

[Mikael Pettersson]

Ion Badulescu writes:
 > On Thu, 20 Feb 2003, Jeff Garzik wrote:
 > 
 > > Ion Badulescu wrote:
 > > > A UP kernel compiled with CONFIG_X86_LOCAL_APIC=y dies a very horrible
 > > > death on an SMP Athlon motherboard (Tyan S2462 and S2468), flooding the
 > > > console with the following messages:
 > > 
 > > IMO just assume this option is just broken, unless you absolutely need it.
 > 
 > My only boxes on which this is a problem are the SMP athlons, and only 
 > with UP kernels...

Chipset?
Is the second CPU installed or not?
If the second CPU is installed, has it been disabled in BIOS?

Relevant config? What combinations of UP_APIC and UP_IOAPIC have
you been using? Has ACPI been enabled or not?

A plain kernel with UP_APIC but no SMP or UP_IOAPIC shouldn't
provoke the kinds of APIC errors you mentioned, unless the APIC
bus is noisy due to a missing second CPU (just a theory).

 > Anyway, I'd like to get to the bottom of this, since I've narrowed it down 
 > so much. Anyone know who submitted the APIC changes in 2.4.10-pre12?

Ingo Molnar, Maciej W. Rozycki, and myself.

 > debug it myself, but I know next to nothing about the APIC. If you know 
 > where to get some documentation, I'm more than willing to give it a shot.

Intel's IA32 manual set, Volume 3, is required reading.

/Mikael