Comment 66 for bug 295251

I was poking around with the Samsung Q45 and discovered a work-around by chance:

  * press (amd release) the blue 'Fn' key *alone*
  * depending on the focus that will open a menu somewhere on the desktop but do not worry and just ignore that for a moment
  * now use the Fn-Up/Down key combinations to adjust the screen brightness as desired
  * finally press the 'Esc' key twice

Outcome: screen brightness adjusted without a messed up keyboard :)