To those who were (or weren't) having the same problem as me (PPP freezes
in kernel 2.2), I found the answer after talking with Clifford Kite on
comp.os.linux.networking (he didn't suggest it, though, he just prompted me
to get on with the diagnosing):
The modem UART type wasn't set right. On boot, the kernel (2.2) reported
ttyS2 to be a 16550A type, which was correct. However, the 0setserial
script decided to set the UART type to whatever it was just underneath the
manual configuration area (can't remember at present). So, if you've got a
problem with PPP freezing under a 2.2 kernel, check your UARTS!!
To see if it works for you, do a 'setserial /dev/ttySx uart 16550A', with
'x' being whatever your modem is. Everything will go back to normal on reboot.
Anyway, I'm off to reinstall; I kinda messed everything up while I was
messing about with everything :-)
Yours,
A very happy "uebergeek" Kris :-)