So having previously said I had solved my wifi problems… it turns out not. Friday for reasons I turned my machine off over the weekend, only to come in once more to find it not working again, no matter how often I clicked reconnect (really, sometimes just trying it a few times seems to help)
This doesn’t make a lot of sense, but the behaviour I seem to be seeing is that somehow the wifi card sometimes gets itself working. Once it has worked correctly it will continue to work (even if I disconnect) until I reboot the machine, at which point the whole process starts again.
I’m currently running with 11n disabled because of historical problems with wifi performance on 11n and this card. When I first did this (modprobe -r iwlwifi; modprobe iwlwifi 11n_disable=1) everything immediately started working. So I made a change in modprobe.d to make this permanent and rebooted.
…at which point everything was non-working again.
My latest experiment was to try to connect with wifi-radar. This didn’t work, but immediately afterwards network-manager started working. So I’m going to have another week of pretending this problem is solved until it next breaks.