I have observed that 'iwlist wlan0 scan' sometimes fails to produce a scan
and manual configuration with iwconfig sometimes fails to produce an
association. I also observed that the Fedora 8 configuration script issues
the command 'ip link set wlan0 up' before configuring the wlan0 and it
always works. I also noted in the Intel documentation that the command
'ifconfig wlan0 up' should be issued before configuing the wlan0. For
manual configuration, I now use
ifconfig wlan0 up
ip link set wlan0 up
iwconfig wlan0 mode Managed
iwconfig wlan0 key xxxxxxxxxxxxxxxxxxxxxxxxxx
iwconfig wlan0 essid mosswap
dhclient wlan0
It always works.
I believe the iwl3945 driver is broken when there are hidden AP's in the
scan list. It appears that the scan list returned to wpa_supplicant is
corrupted which is why the wpa_supplicant setting ap_scan=2 does not for
hidden AP's.
With hardware scanning enabled as a module option, it appears that iwl3945
does both a background scan and a scan by ssid when the ssid is set unlike
ipw2200 which does background scans constantly and only does scan by ssid
when it is requested.
Bill Moss