I have a HP elitebook 8540w, using a I5 540m. I get terrible battery life, so I figured I'd try undervolting the cpu. Unfortunately, the only way to this that I can find is PHC. The wiki shows how to install it, but using sysvinit, which I have replaced with systemd. I am also using the linux-ck-corex kernel from the repo-ck repo. Can someone give me a step by step on how to install PHC? Or does anyone have a better idea on how to undervolt this thing?