ipw2200 auto scanning and roaming

[Bill Moss <bmoss CLEMSON EDU>]

If the module parameter is set to associate=1 (the default), ipw2200 
does the following scans and tries to automatically associate if it 
finds a suitable AP, same as NM does.

unassociated
-- speed scan (not currently implemented)
-- regular scan with an interval #define SCAN_INTERVAL (HZ / 10)
   currently the default

associated
 -- regular scan with an interval #define SCAN_ASSOCIATED_INTERVAL (HZ)
    This feature is not currently turned on.

This went unnoticed by me until version 1.1.2 when the scan completion 
event was implemented.
Now iwevent shows about 3 scans per second. The hardware cannot do the 
10 scans called for. The flood of scan completion events produced often 
confuses NM making it unstable. Commenting out the ipw2200 scan 
completion event code, makes NM more stable simply by not reporting the 
stream of scans completion events that occur prior to association.

ipw2200 also has roaming code that is in some ways similar to NM code. 
When I walk between buildings the ipw2200 roaming code switches AP's so 
fast the NM doesn't usually detect it.

I can turn off ipw2200 automatic association (associate=0) and roaming 
(roaming=0), but NM is a lot slower to connect if I do. Experiments 
continue.

--
Bill Moss
Professor, Mathematical Sciences
Clemson University