FreeBSD 6.x SMP amd64 hang on dual Xeon after "shutdown -r"

[Guy Helmer]

On systems without PS/2 keyboard controllers, after issuing a "shutdown 
-r", the system winds down to this point:

Shutting down ACPI
Stray irq9
Rebooting......
cpu_reset: stopping other CPUs

and it no longer responds to the keyboard - only reset or power cycling 
will bring it out of this state.  Does the Opteron or EMT64-enabled Xeon 
not reboot on a triple fault like i386 CPUs do?  (A triple fault is what 
umapping all the virtual memory causes, doesn't it?)

Any ideas?
Guy

-- 
Guy Helmer, Ph.D.
Principal System Architect
Palisade Systems, Inc.