powertop is bugged since the introduction of systemd in Linux, from what I've heard. But whatever, the fact is that
powertop doesn't work anymore. It is usefull to check your power consumption, but no more to optimize it*.
There are 2 tools designed to optimize laptop's power consumption :
=> Even if
laptop-mode-tools is present in the official repositories (from Ubuntu), I rather use
tlp, because you have less configuration to make :
Install TLP from author's PPA : **
sudo apt-add-repository ppa:linrunner/tlp
sudo apt-get update
sudo apt-get install tlp tlp-rdw
Start tlp without restarting (automatically started at boot, unless you uninstall it) :
sudo tlp start
Note : the
tlp optimization will not work right away, you should plug/unplug your laptop or reboot it in order to notice a difference.
tlp to manage PCI power-consumption (experimental option, works for me) :
sudo sed -i 's/RUNTIME_PM_ALL=0/RUNTIME_PM_ALL=1/g' /etc/default/tlp
Configure TLP further :
You can read and modify the configuration file (in /etc/default), it is well commented, with :
gksu gedit /etc/default/tlp
Everytime you change the configuration file, please plug/unplug your laptop, and then run powertop to check the state of your power-consumption. You may also use
sudo tlp restart, or restart.
powertop : it is an old tool and the vm.writeback file is not in the same place it once was, so
powertop will always
tell you that it is in "BAD" state, even if it is not.
So, by default with
tlp, you should have all the states to "GOOD"
except this one. But you don't need to do anything, it actually is
powertop just can't see it.
tlp : if you have a ThinkPad (and ONLY if you have one), you'll also need to run
sudo apt-get install tp-smapi-dkms