I'm trying to build an SMP kernel that will boot on my laptop.
The laptop is HP Pavilion DV9408 with an Athlon 64 X2 Dual Core TK-53
cpu.
The problem I'm having is that with an SMP kernel, the machine freezes
during bootup 8 times out 10. A uniprocessor kernel boots-up with no
problems. However on those rare occasions when the SMP kernel boots up
successfully, then it runs very well.

**Bootup Output**
"Total of 2 processors activated (6835.77 BogoMIPS)
ExtINT not setup in hardware but reported by MP table
ENABLING IO-APICS IRQs
....TIMER: vector=0x31 apic1=-1 pin1=-1 apic2=0 pin2=0
....trying to set up timer (IRQ0) through 8259A...
.... (found pin 0)...failed
....trying to set up timer as Virtual Wire IRQ...failed
....trying to set up timer as ExtINT IRQ... works"

The freeze occurs at his point and I have to use the power button
to turn machine off - then on again.

I've built an SMP kernel using 2.6.22.10, 2.6.22.12, 2.6.23,
and 2.6.23.1 with the same results for all.

**Observations**
(1) Vista boots OK on the same machine everytime.
(2) Uniprocessor kernels boot OK everytime.
(3) Usually after booting up Vista, an SMP kernel boots up OK,
but may not the next time. Have had a maximum of 4 consecutive
successful bootups with an SMP kernel (2.6.23.1), after which
a freeze occurs. Then I reboot to Vista, and keep trying to
boot the SMP kernel. Usually I just give up after 3 tries and
use the uniprocessor kernel.
(4) If I try boot an SMP kernel after running a uniprocessor
kernel machine *WILL* freeze.
(5) If I try boot an SMP kernel after running an SMP kernel
the machine *MAY* freeze.
(6) Once it boots successfully, an SMP kernel is just as
reliable as a single processor kernel.

I set the pertinent parts of the kernel config as follows:
> Processor family=Opteron/Athlon64/Hammer/K8
> Symmetric multi-processing support=y
> Subarchitecture Type=pc-compatible
> HPET timer support=y
> Max number of CPUs=2 (there are only 2 cores)
> Multi-core scheduler support=y

As far as I can understand, the above are the only items related to
an SMP kernel. Are there any others?
(If it will help I can provide output of lspci, usb, etc...)

Any insight into this problem would be really appreciated!
Thanks all.