I guess I assumed the irq or no irq was in the config, [..]

If you specify an IRQ in the config file, then you can use either the
polled or interrupt-driven device.  If you don't specify an IRQ, then
it's listed as `polled' during the probe, and you can only open the
polled device.

There is no general way to figure out if the port has an interrupt or
not; any method I've come up with invariably fails on some hardware or
other.  Thus, it's up to the sysadmin to figure that out.


------------------------------------------------------------------------------