during Summer period I used a usb dongle with stir4200 chip.
I used it to connect my Nokia 6610 cell phone and made GPRS connection.
To make phone and irda dongle to work I had to insmod stir4200.o with
rx_sensitivity=5 tx_power=3 qos_mtt_bits=1
other values for rx_sensitivity work too, but your mileage may vary :)
During connection, from time to time, I got "state_link_escape(), state
not defined" kernel message, but connection goes on.
Now I cannot produce a irdadump output; if it can helps I'll see to make
Hope this infos are usefull.