No serial ports found after 2.6 kernel upgrade

[Tony Terlecki <lists@tonyterlecki.co.uk>]

I upgraded my kernel a few weeks ago and, because I rarely use my serial
ports (only for the odd FAX), I never noticed they were missing until
today. I'm running 2.6.15 on a Testing build and have compiled in most
of the serial driver support for good measure, i.e.:

CONFIG_SERIAL_8250,
CONFIG_SERIAL_8250_ACPI
CONFIG_SERIAL_8250_EXTENDED
CONFIG_SERIAL_8250_MANY_PORTS
CONFIG_SERIAL_8250_SHARE_IRQ
CONFIG_SERIAL_8250_HUB6
CONFIG_SERIAL_8250_NR_UARTS=6

but still the serial ports are not detected on bootop. I also note that
whereas previously I had /dev/ttyS0 and /dev/ttyS1 they are now missing,
although I don't think those devices missing actually means that the
kernel won't find the hardware on boot.

Any ideas on how to proceed? When I boot into the old 2.4 kernel the
serial ports are identified without problem with following boot
information:

Serial driver version 5.05c (2001-07-08) with HUB-6 MANY_PORTS MULTIPORT
SHARE_IRQ SERIAL_PCI enabled
ttyS00 at 0x03f8 (irq = 4) is a 16550A
ttyS01 at 0x02f8 (irq = 3) is a 16550A

Maybe there is something outside of the serial drivers support I need to
include in the kernel build?

Thanks,

-- 
Tony Terlecki
lists@tonyterlecki.co.uk