How to enable control keyboard backlight in xmonad?

I'm using xmonad -tiling window manager- and lux to control backlight but keyboard backlight via fn doesn't work. Does anyone know a solution?

Thanks for help.

One solution is to run xmonad on top of a desktop environment such as Mate or Gnome-Flashback. This makes things much peaceful since the DE takes care of managing systrays / functions keys / disk mounts / authentication and other small things that might take a long time figuring out on a pure xmonad setup

I found a solution to fix Fn for backlight & volume:

• In ~.xmonad/xmonad.hs, add these lines at the top of the file:

  import Graphics.X11.ExtraTypes.XF86 
  import XMonad.Hooks.DynamicLog 
  import XMonad.Util.EZConfig(additionalKeys)
  

  and add these lines below --key bindings

      , ((0                   , xF86XK_AudioLowerVolume),  spawn "pactl set-sink-volume 0 -1.5%")
      , ((0                   , xF86XK_AudioRaiseVolume),  spawn "pactl set-sink-volume 0 +1.5%")
      , ((0                   , xF86XK_AudioMute),         spawn "pactl set-sink-mute 0 toggle")
   -- , ((0                   , xK_Print),   spawn "shutter")
      , ((0                   , xF86XK_MonBrightnessUp), spawn "lux -a 2%")
      , ((0                   , xF86XK_MonBrightnessDown), spawn "lux -s 2%")
  

Now Fn works fine for volume and backlight in my Samsung Note Book 9.