Tutorial brightness in Trisquel-mini (lxde) for Samsung users

If the brightness keys (Fn+F2 and Fn+F3) don't work than you may tray this:

1)
sudo apt-get install xfce4-power-manager

2)After this must to go in: /etc/xdg/lxsession/Trisquel-mini
and edit the file "autostart" and replace:

@gnome-power-manager

with:

@xfce4-power-manager

3)
sudo leafpad /etc/default/grub

change the line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
to:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

save file

4) than in terminal:
sudo update-grub2
sudo reboot