I did an upgrade from Hardy to Karmic on an Ubuntu Box that experienced problems with the Atheros PCI wi-fi card in it. The signal was weak (the signal is weak indeed, but it uses to work in Windows, so I expect it to work also in Linux)
The box wasn’t upgrade in a while, so I decided and upgraded the Hardy at first. The wi-fi issue went away. I decided to go to Karmic, as I needed some features from it.
After a flawless upgrade, the reboot went just fine, but there’s no wireless card in the Network Manager applet or in network-admin.
$>Iwconfig
shows no wireless capable card.
The thing is weird, as everything seems to be in place. The Proprietary driver manager shows nothing relevant. Before screwing everything up, I decide for a quick search and the first result itself is relevant and helped me to fix the problem.
Have a look to https://help.ubuntu.com/community/WifiDocs/Driver/Atheros and you’ll find the relevant lines.
“Reboot. If it’s still not working than it is very likely you have ath5k being blacklisted somewhere. Blacklisting may have occurred if you are coming from a Hardy upgrade and/or did not uninstall the madwifi driver before doing this.”
I just did a quick:
$>grep -r “ath5k” /etc/modprobe.d/
and found an entry in blacklist-ath_pci.conf. I commented it out by editing it with nano (requires root privileges of course)
$> sudo nano blacklist-ath_pci.conf
and after a reboot everything is ok.