VIA spurious hang on 2.6.23.1

From: Jan Engelhardt
Date: Tue Nov 20 2007 - 10:14:40 EST


Hi,


I've got some semi-embedded device here, a plain consumer-grade x86 with
a VIA Nehemiah/Eden C7. After a while it just locks up, but neither is
that deterministic nor does it give out kernel messages. CPU Frequency
Scaling (which has been known to be a problem with this CPU) is already
disabled.

I tried the "nohz" boot option to but until it finally hangs (which may
take hours or days) I can't say for sure whether it works. It shall be
noticed that watching the interrupts in /proc/interrupts (using
/usr/bin/watch e.g.) shows that the IRQ0 interrupt does not fire at 100
Hz, even with nohz, but more like 40-60 Hz. Also, the LOC line in
/proc/interrupts is not increasing at all (presumable due to the APIC
emulation).

dmesg:
[ 0.000000] No local APIC present or hardware disabled
[ 0.000000] mapped APIC to ffffb000 (011ec000)
[ 39.983680] Local APIC not detected. Using dummy APIC emulation.
[ 39.983426] CPU0: Centaur VIA Nehemiah stepping 08
[ 40.545396] PCI: VIA PCI bridge detected. Disabling DAC.
[ 40.545564] PCI: Bypassing VIA 8237 APIC De-Assert Message
[ 41.803665] PCI: VIA VLink IRQ fixup for 0000:00:0f.0, from 255 to 5

Ideas be welcome, although I guess it's pretty much trial-and-error on
my side :(
2.6.21 seemed to be a last known good one, though I'd stick with a
distro kernel as usual.


thanks,
Jan
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