'Unexpected interrupt' on a TI 900CDT (ignore_int in head.S ?)

Martin Pool (m.pool@pharos.com.au)
26 Jul 1997 09:20:55 -0000

I have a TI 900CDT laptop with RHL4.2 (kernel 2.0.30) which is working
perfectly in all respects but one: the suspend/resume mode doesn't
work at all.

The RHL kernels don't have APM support compiled in: I built a custom
2.0.30 which did use APM. The APM functions worked (e.g. the machine
powered off on shutdown, and it could report battery life), but it
still froze on resume. Of course, perhaps I was using the wrong

This laptop can be suspended either by a key combination or by closing
the lid. In either case, it powers off OK. When I open the lid
again, the screen powers up, the machine seems to run for ~0.5s, and
then it freezes completely. Generally, but not always, the HD light
is on. The machine prints the message

Unknown interrupt

on the console and stops without another word. C-A-D doesn't work,
and usually not even the soft power switch: I have to pull out the

Suspend/resume works fine in NT 4.0. (Of course, NT can't see the
network card...)

The problem persists even in single-user mode, when only init, kswapd,
kerneld and bash are running, which would seem to eliminate a problem
with PCMCIA.

Suggestions would be really appreciated. If nothing else, how can I
obtain more information on which particular interrupt is causing
trouble? The message seems to come from ignore_int in
linux/arch/i386/head.S. Without more information I can't guess how it
got there.

Martin Pool <m.pool@pharos.com.au>
Pharos Business Solutions

"The math is perfect. The computers are bad. The networks hideous. The people worse." -- Bruce Schneier on "Why Crypto Is Harder Than It Looks"