O Arch Linux tem o seguinte a dizer sobre o xbacklight :
Brightness can be set using the xorg-xbacklight package.
Note: xbacklight only works with intel. Radeon does not support the
RandR backlight property. xbacklight currently does not work with the
modesetting driver.
To set brightness to 50% of maximum:
$ xbacklight -set 50
Increments can be used instead of absolute values, for example to
increase or decrease brightness by 10%:
$ xbacklight -inc 10
$ xbacklight -dec 10
If you get the "No outputs have backlight property" error, it is
because xrandr/xbacklight does not choose the right directory in
/sys/class/backlight
. You can specify the directory by setting the
Backlight option of the device section in xorg.conf
. For instance, if
the name of the directory is intel_backlight
, the device section can
be configured as follows:
/etc/X11/xorg.conf
-------------------
Section "Device"
Identifier "Card0"
Driver "intel"
Option "Backlight" "intel_backlight"
EndSection
O seguinte funcionou para mim no Debian Stretch LXDE.
-
Verificou o diretório da luz de fundo: ls /sys/class/backlight
. Por acaso tenho intel_backlight
.
-
Para obter o identificador, eu corri xrandr --verbose
. O meu passou a ser 0x72
.
-
Verificando /etc/X11/
, não encontrei xorg.conf
, então criei o meu e digitei a informação que encontrei:
Section "Device"
Identifier "0x72"
Driver "intel"
Option "Backlight" "intel_backlight"
EndSection
-
Eu reiniciei. Funcionou a partir daí.
-
Como o LXDE roda o openbox, eu editei ~/.config/openbox/lxde-rc.xml
e inseri os seguintes atalhos de teclado:
<!-- Increase backlight 10% -->
<keybind key="XF86MonBrightnessUp">
<action name="Execute">
<command>xbacklight -inc 10</command>
</action>
</keybind>
<!-- Decrease backlight 10% -->
<keybind key="XF86MonBrightnessDown">
<action name="Execute">
<command>xbacklight -dec 10</command>
</action>
</keybind>