It's possible, that it's not implemented in CM11 yet. If it works on CM10.2, I'll stick with that if it's important to you. I think it will get fixed by upstream changes at some point. Or does it work on other devices running CM11?
Besides that, do you use the CM11 build with 3.0.x or 3.4.x kernel? You should try the most up-to-date version.
Never touch a running system.