IRDA

For the built-in IRDA port to work, you'll have to select "IRDA" and not SIR in the BIOS configuration.

After that, it's a simple matter of editing /etc/irda.conf to use ttyS1 as device:

#irda.conf Version: 1.0
IRDADEV=/dev/ttyS1
#DONGLE= # specify dongle type
DISCOVERY=-s
ENABLE=yes # if you do not need to start irattach, set "no"
						

After restarting the irda daemon, irdadump should produce the following output:

02:23:40.468495 xid:cmd ea87bde0 > ffffffff S=6 s=0 (14) 
02:23:40.558399 xid:cmd ea87bde0 > ffffffff S=6 s=1 (14) 
02:23:40.648383 xid:cmd ea87bde0 > ffffffff S=6 s=2 (14) 
02:23:40.738371 xid:cmd ea87bde0 > ffffffff S=6 s=3 (14) 
02:23:40.828355 xid:cmd ea87bde0 > ffffffff S=6 s=4 (14) 
02:23:40.918350 xid:cmd ea87bde0 > ffffffff S=6 s=5 (14) 
02:23:41.008328 xid:cmd ea87bde0 > ffffffff S=6 s=* mhcln03 hint=0400 [ Computer ] (23)