RF_KILL sucks!

This is not the first time that I have troubles with the RF-kill “feature” as reported on this blog.

Recently I set up an old notebook. I did a clean Linux network install of Debian Lenny. Everything worked fine, all hardware was detected properly.

But it took not long to find out that the wifi does not work although the card was detected correctly. `lspci` showed that it is a IPW2100 which is a pretty well-known wifi adapter. After unloading and loading the appropriate kernel module, it was reported that RF_KILL is enabled.

The notebook is an old Toshiba notebook. It has a wifi indicator LED and the symbols on the keyboard showed that Fn+F8 should enable it. But simply nothing happens. I made sure that the Fn key and the F8 key both work. I expected the kernel to report something but it didn’t.

I have seen various methods of enabling and disabling wifi: soft keys, hard keys, key combinations on the keyboard, simply just enabling/disabling it by software, and BIOS disable/enable. And of course combinations of those methods.

I restarted the Toshiba notebook to have a look at the BIOS setup. Unfortunately, its BIOS didn’t allow any settings. I tried to “reset to factory defaults” but it didn’t change anything. Then I tried to find a software enable option. Luckily I’m working on Linux, thus I have direct access to most hardware features. In this case the RF_KILL enable/disable option is found in the special file /sys/devices/pci0000:00/0000:00:1e.0/0000:02:0a.0/rf_kill. Writing neither 0 nor 1 to it didn’t change anything. This indicated that there must be some other hardware enable/disable method.

I assumed to have found a BIOS bug…which would not be the first time. And flipped the notebook to gather the product specification and I found something…