ack & cts timeout and slottime for log distance links in prism54 driver

Hello!

In madwifi driver for atheros based cards, there is possibility to 
change ack and cts timeout values, and slottime, according to distance 
between transmitter and receiver. They recommend to adjust these values 
for every link longer than 300 meters. I have a link of 2 kilometers, 
and big trouble with performance with Intersil Frisbee card (in same 
setup, acx100 based card works excellent, giving 500kB/s throughput and 
very stable ping reply od about 2ms, but this is only b standard). Now 
with Intersil Frisbee card ping is not stable, and speed.. shame to say 
:-( Yes, at 1M bitrate.. for comparision, acx100 runs on 11M without any 
problem.

Now, I wish to try some tweaking, to make link better if possible. First 
thing, I would like to try adjust ack & cts timeouts, if that is 
supported with this driver. Can someone put some light on these please? 
If that doesn't help, then I would like to try do more troubleshooting 
with your help, but first I would like to adjust these values if possible.

Thanks a lot,

Ivan Toman

Croatia