How to permanently turn off wi-fi power management in Ubuntu – Fixes loss of wi-fi connection when on battery power.
My better half recently installed Ubuntu 11.04 (Natty Narwhal) on her notebook and quickly realised that when she removed the AC power lead the wi-fi connection would cut out, only resuming when she plugged the power lead back in. This meaning she could not access or use wi-fi whilst running on battery power alone – which kind of defeats the purpose of having a laptop/notebook if you need the power cable plugged in at all times to surf the web.
Anyway, the root of the cause is that Ubuntu’s new default power management setting turns ‘on’ the power management for the wi-fi device when on battery power. Meaning you lose the wi-fi connection if you unplug the AC power from your laptop/notebook. There is a simple little solution that can fix this problem.
All we need to do is run a couple of commands and create or edit a file in /etc/pm/power.d that will basically tell Ubuntu to turn the wi-fi power management off and to keep it off permanently when in battery mode, so we can use the wi-fi wherever and whenever we choose to.To apply the fix, follow the steps below but make sure you do NOThave the AC power plugged into your laptop/notebook, follow the steps on battery power.