IDE "lost interrupt" on SMP

[Paul Flinders <paul@dawa.demon.co.uk>]

I decided to replace the Celerons on my Asus P2B-D with something
a little faster so I bought a new 1Ghz PIII** (it would have been two but
the local dealer only had one in stock).

However I can't boot any SMP configured kernel. It gets as far as
the partition check and then starts printing "hd<x>: lost interrupt"
after than it proceeds _very_ slowly to print the partitions and
then grinds to a halt as it tries to mount the root fs (I suspect that
it hasn't actually crashed but that disk I/O is proceeding extremely
slowly).

Configuring the kernel for single processor works and boots OK
- this is true for all the kernels (2.2.x and 2.4.x including 2.4.7)
that I've tried.

I thought that SMP kernels were OK with just one processor. Do
I need to add the second one or could there be something else
wrong.

** Actually underclocked at 750Mhz as the BX chipset only goes to
100 Mhz FSB