I've got a Dell SC1420 that has two Intel Xeon processors.  So far
I haven't been able to get it to work using both processors.  It seems
to run ok with just a single processor.  Turning on "options MULTIPROCESSOR"
makes it not work.  The reason appears to be some variation on 
interrupts not getting through.
	After a little bit of playing around with I noticed what seems to be
an interrupt getting to the ioapic but the CPU doesn't notice:
 ioapic0: int9 f1a0<vector=a0,delmode=1,pending,actlo,irrpending,level,dest=0> 0<target=0>
                                        ^^^^^^^       ^^^^^^^^^^
int9 seems to be wired up to the ide controlled:
 allocated pic ioapic0 type level pin 18 level 6 to cpu0 slot 9 idt entry 98
 piixide1: using ioapic0 pin 18 (irq 9) for native-PCI interrupt

and I get several timeouts before the drives are detected (cd0, wd0 and wd1)
but they eventually show up.  Further access doesn't work.  Trying to
netboot off wm0 appears to run into a similar problem: I get output on the
wire but input interrupts are never received.

I've determined that _some_ interrupts gets through, since setting a
breakpoint on either schedcpu or hardclock drops me into ddb.  However,
hitting ctrl-alt-esc does not work.

So, before I spend too much time playing around with stuff that I don't
entirely understand, does anyone have some ideas on what's going wrong?
(and hopefully what I can do to figure out how to fix it?)

eric