I have a MacBook Pro 5,5 running Ubuntu 11.04 Natty amd64.
About one time every hour, my wifi connection speed goes really slow (I guess it goes in to powersaving mode), and I have to run iwconfig eth1 power off (which I have packaged in a bash script for ease) to get back to normal speed.
Is it possible to set the power option to "off" permanently so I don't have to do this manually every time the wifi driver decides to go in to powersaving mode?