Re: lockup at boot with kernel 2.6.14...
I had a similar problem with an older kernel when discover loaded the ehci
modules. It was only, when an USB 2.0 devices was attached to the USB port, a
card reader in this case. Chipset is ATI Xpress 200 North- and ULi
southbridge, I think USB is in the SB. Kernel was 2.6.11 i386 and amd64. In
i386 it hung for a minute or two and then continued (haven't tested if
cardreader worked afterwards), amd64 just hug completely.
My problem was solved with 2.6.12 at least for i386. Maybe there's a similar
problem in your (although newer) kernel rev. You might want to try to move
away the corresponding kernel module (or otherwise disable its loading) just
to see what happens. Be careful, it might sit in the initrd.