Comment 129 for bug 121439

 A couple a weeks ago I´ve upgrades to gutsy wireless was not working I
follow the trick to turn on/off the wireless switch while connecting and
this worked 50% of the time.

But I've keep feisty kernel 2.6.20 for the "just in case" situation and when
booting with this kernel I don't have problem connecting to public or
secured spots. But when booting this kernel I've got several segmentation
faults.

The iwlwifi site says that the driver still is in a development, I've tried
several snapshot in the past and is not as estable as ipw3945, ie lost
connection under heave use, can't connect after suspend, etc., so far this
issues are being solved, but IMHO is not ready for a production release.

If you want to load iwl3945 on boot you should blacklist ipw3945, ie create
a file blacklist-ipw3945 under /etc/modprobe.d, which contains the line

blacklist ipw3945

This will prevent the automatic load of this module and iwl3945 should be
loaded instead.

 PD: I was doing this from my memory so better take a look at ubuntu wiki
howto blacklist a module. If you want to undo this just remove the file
blacklist-ipw3945.