I believe currently lxqt-config-brightness only supports setting monitors' backlights via ACPI (/sys/class/backlight/). Many external monitors do not use ACPI but instead DDC/CI (https://wiki.archlinux.org/title/Backlight#External_monitors). It'd be wonderful if software backlight setting for DDC/CI monitors could be incorporated into LXQt.
Current Behavior
'Backlight' slider is greyed out in lxqt-config-brightness due to the external monitor not having ACPI backlight support.
Possible Solution
Look at ddcutil and see how it sets backlights. (Note: ddcutil requires the i2c-dev kernel module)
Context
Software setting of backlight is very convenient, especially so when not on laptops with dedicated keyboard keys for setting screen brightness.
I believe currently
lxqt-config-brightnessonly supports setting monitors' backlights via ACPI (/sys/class/backlight/). Many external monitors do not use ACPI but instead DDC/CI (https://wiki.archlinux.org/title/Backlight#External_monitors). It'd be wonderful if software backlight setting for DDC/CI monitors could be incorporated into LXQt.Current Behavior
'Backlight' slider is greyed out in lxqt-config-brightness due to the external monitor not having ACPI backlight support.
Possible Solution
Look at
ddcutiland see how it sets backlights. (Note: ddcutil requires thei2c-devkernel module)Context
Software setting of backlight is very convenient, especially so when not on laptops with dedicated keyboard keys for setting screen brightness.
System Information