setserial?setserial is a program which allows you to look at and change
various attributes of a serial device, including its port address,
its interrupt, and other serial port options.
It was initially written Rick Sladkey, and was heavily modified
by Ted T'so tytso@mit.edu, who also maintains it.
The newest version is 2.10,
and can be found on the Linux FTP sites. You can find out what version
you have by running setserial with no arguments.
When your Linux system boots, only ttyS{0-3} are configured,
using the default IRQs of 4 and 3. So, if you have any other serial
ports provided by other boards or if
ttyS{0-3} have a non-standard IRQ, you must use this program
in order to configure those serial ports. For the full listing of
options, consult the man page.