Re: enabling IOAPIC on C3 processor?

From: Mikael Pettersson
Date: Tue Mar 15 2005 - 07:37:01 EST

jerome lacoste writes:
> I have a VIA Epia M10000 board that crashes very badly (and pretty
> often, especially when using DMA). I want to fix that.
> Serial console + magic SysRQ didn't help so I am going the nmi
> watchdog way. But in order to have nmi watchdog I need APIC, right?
> The C3 processor seems to support IOAPIC.
> (
> But:
> - I don't see anything in the BIOS related to APIC.
> - grep APIC /lib/modules/`uname -r`/build/.config shows me that all
> APIC options are 'y'.
> - dmesg | grep APIC tells me "no local APIC present or hardware disabled".
> - adding lapic kernel parameter doesn't change that.
> - and of course, nmi_watchdog=1 or 2 gives me NMI count 0 in /proc/interrupts.
> Did I miss something when it comes to enabling IOAPIC support on C3 processor?

Unless you have a pre-release engineering part for a future product,
then your C3 has no local APIC, and hence no I/O APIC functionality.

I know some C3 specs pages list I/O APIC support, but if you look in
the datasheets for current products you find zero APIC support.
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