I finally found a way to fix my WLAN on an EeePC, by reinstalling ath9k from an old compat-wireless release as described here:
Linux on the EeePC 1001p: Fixing wireless
However, it only works after:
If I 'networking start' with the ath9k pre-loaded by the kernel, I get a "wlan0: no such device" error.
This feels like there still is an old version of the ath9k driver on my computer which gets loaded by the kernel on boot time.
How would I find out if there are two drivers installed, and what tells the kernel which ath9k to load when booting?
OK, 'dmesg|grep ath9k' gives me a line that says "Failed to initialize device".
Although, 'modprobe ath9k; /etc/init.d/networking start' does not work. I really have to 'rmmod ath9k; modprobe ath9k' to get it to work.