5.2.1-RELEASE, SMP, ACPI, Interrupt loop?

[David E. Cross]

I recently upgraded my old P2B-DS dual processor (p2-450Mhz) machine to
5.2.1 everything seemed to be going well, and in fact I didn't notice it
until recently, but even when the machine is idle it is spending 50% of
its time in an interrupt loop (since I have 2 processors, the second one
is free for me to use, since I had only been doing serial tasks I hadn't
had cause to notice).

If I turn off ACPI I keep both processors and everything else,
additionally the interrupt problems go away.  One further note is on
shutdown, right after ACPI is disabled I get a mangled line of text, one
time in particular it said "stray irq 2"; no idea if it was really irq 2,
it could have been "12", it seems random characters are dropped under the
IRQ storm.

Has anyone seen this?  Better yet, anyone know what I can do about it?
I'd like to keep ACPI support if possible (for things like actually
shutting the computer off in response to ACLine/UPS failure.)

Cheers,
-- 
David E. Cross