Yesterday I tried to connect an old notebook which has no Wifi adapter to the Internet through my HP 2510p. Usually not a big deal; connect through an Ethernet cable, configure IP addresses on both sides, enable packet forwarding and configure an iptables masquerading rule.
But it didn’t work. As soon as I connected the network cable my Wifi was disabled. My first guess was that the network-manager executes some ifup/down scripts. I often made bad experiences with the network-manager as soon as you try to manually reconfigure the network.
Thus, I disabled it as usual but it didn’t change the WLAN-switch-off behavior. I reloaded the iwlagn kernel module, without success. I browsed the web to find somebody with a similar problem, unfortunately without success.
The following kernel message appeared suddenly after connecting the cable.
iwlagn 0000:10:00.0: RF_KILL bit toggled to disable radio.
Rfkill showed that the Wifi is disabled by hardware. This led me to the conclusion that this could be some HP hardware “feature”. I rebooted into the BIOS. In the Built-In Device Configuration menu there is the option LAN/WLAN-Switching. The BIOS manual explains that “With this option LAN/WLAN-Switching is enabled/disabled” — very helpful…
Nevertheless, disabling this solved the problem 🙂