Comment 4 for bug 121415

Also seems to happen after resume from suspend on HP Compaq nc6320.

sudo killall ipw3945f-2.6.22-6-generic
sudo rm /var/run/ipw3945d.pid
sudo rmmod ipw3945
sudo modprobe ipw3945

seems to get it lively again for me (Although I do recall having to restart some core bits of network manager for it to notice the new interface.)

Unfortunatly, the regulatory daemon stops you just doing rmmod ipw3945 directly (the module is in use). I wonder if there is some way the module can not flag its self as being "in use" with the regulatory daemon as its only user, but instead kill the daemon when the module is unloaded.