Xeon / SMP hang after SMP launches

[eecue]

I just finished building a 5.1-RELEASE SMP kernel.  When the kernel
boots it ends up hanging right after the 3 other processors are  
recognized.

the last messages i see on the screen are:
unknown: <PNP0303> can't assign resources (port)
unknown: <PNP0501> can't assign resources (port)
unknown: <PNP0501> can't assign resources (port)
unknown: <PNP0401> can't assign resources (port)
APIC_IO: routing 8254 via IOAPIC #0 intpin 0
Timecounters tick every 10.000 msec
ad0: 76319MB <WDV WD800BB-00DKA0> [155061/16/63] at ata0-master UDMA100
ad0: 76319MB <WDV WD800BB-00DKA0> [155061/16/63] at ata0-slave UDMA100
ad0: 76319MB <WDV WD800BB-00DKA0> [155061/16/63] at ata1-master UDMA100
ad0: 76319MB <WDV WD800BB-00DKA0> [155061/16/63] at ata1-slave UDMA100
SMP: AP CPU #3 Launched!
SMP: AP CPU #2 Launched!
SMP: AP CPU #1 Launched!

then it just hangs... i'll try leaving it overnight to see if it  
eventually makes it.

I've been digging through the freebsd-smp list archives
and i have found several threads that pertain to my problem:

http://docs.freebsd.org/cgi/getmsg.cgi?fetch=37362+0+archive/2003/ 
freebsd-smp/20030803.freebsd-smp (fix didn't work)
http://docs.freebsd.org/cgi/getmsg.cgi?fetch=14497+0+archive/2003/ 
freebsd-smp/20030824.freebsd-smp (no solution listed in thread)

does anybody have any idea what the problem is here?

btw if i don't disable ACPI  the kernel panics before it even gets to  
the part where
it hangs.

-eek

....
Aaron David Bullock
eecue : programmer / designer / admin / human
http://eecue.com/
anything is possible