I have a Thinkpad e555 with AMD A6 7000 and R4 graphics card.
I have already installed the new version of AMD video drivers.http://www.support.lenovo.com/
After installing new drivers, ver.15.300.1025.0 (and the previous 15.200.1060.0) , the brightness bar control (from Settings Panel) disappeared and the brightness keys (F5 and F6) stopped working.
Restoring the previus driver version brings back all the working controls.
How can i solve the problem?
Thank you for your attention.
Sorry for my english..