Similar problems.
I have a Samsung XE700T1C with Win 8.1.
Screen brightness auto adjusts to environmental light conditions (even though I disabled in Power Options). Brightness cannot be manually set, neither form Charm menu, keyboard nor any other places.
I have upgraded to the newest Intel driver: 9.18.10.3222.
Still the same problem. Does anybody know which driver would work properly under Win 8.1? Or any other soultion?
Thx,
Csaba