Comment 114 for bug 257827

(In reply to comment #12)
> (In reply to comment #11)
> >
> > Replying to myself: it seems that there's an xfconf key
> > change-brightness-on-key-events which one can set to false in order to prevent
> > xfpm to touch the brightness. Problem is that the notification seems a bit
> > confused by that, but at least it brings the 16 levels back.
>
> Could you say where we can find this key?
> $ xfconf-query -c xfce4-power-manager -l
> /xfce4-power-manager/brightness-level-on-battery
> /xfce4-power-manager/brightness-on-ac
> /xfce4-power-manager/brightness-on-battery
> /xfce4-power-manager/critical-power-action
> /xfce4-power-manager/critical-power-level
> /xfce4-power-manager/dpms-enabled
> /xfce4-power-manager/dpms-on-battery-off
> /xfce4-power-manager/dpms-on-battery-sleep
> /xfce4-power-manager/enable-cpu-freq-control
> /xfce4-power-manager/general-notification
> /xfce4-power-manager/inactivity-on-ac
> /xfce4-power-manager/inactivity-on-battery
> /xfce4-power-manager/lid-action-on-ac
> /xfce4-power-manager/lid-action-on-battery
> /xfce4-power-manager/power-button-action
> /xfce4-power-manager/show-tray-icon
> /xfce4-power-manager/sleep-button-action
> /xfce4-power-manager/spin-down-on-battery

It doesn't exist by default, you have to create it:

xfconf-query -c xfce4-power-manager -n -t bool -p /xfce4-power-manager/change-brightness-on-key-events -s false