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Message-ID: <16950.54895.527127.21123@alkaid.it.uu.se>
Date: Tue, 15 Mar 2005 13:34:55 +0100
From: Mikael Pettersson <mikpe@csd.uu.se>
To: jerome lacoste <jerome.lacoste@gmail.com>
Cc: lkml <linux-kernel@vger.kernel.org>
Subject: Re: enabling IOAPIC on C3 processor?
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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.
 > (http://www.via.com.tw/en/products/processors/c3/specs.jsp)
 > 
 > 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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