Boot hangs on Toshiba Tecra 9000 in Mdk 10.1, default kernel

Can anyone suggest how I might diagnose and fix the problem described below?
(I could recompile the kernel with different options for example, if I knew
what options to try.)

First error:
Initialising USB controller (uhci-hcd) [FAILED]

Continues for a bit, no more errors, then...
Activating swap partition: [OK]

Then it hangs.

Further debugging suggests the hang is when it loads intel_agp. If I set
nousb on boot command line, instead of hanging there it gives a stack dump
and hangs later when initialising firewire. If I set nousb nofirewire it
hangs later still, in 'icfonfig eth1'. So lots of things apparently broken.

Now, Mandrake 10.0 kernel 2.6.3-25mdk works very well on this laptop.
Knoppix 3.7 kernel 2.6.9 also works ok. What could have changed in
Mandrake 10.1 to cause this?

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