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misc: update copyright years
author David Demelier <>
date Wed, 01 Feb 2023 12:26:10 +0100
parents 6081cc143d37
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backlight INSTALL

Supported systems

- Linux: requires video ACPI module,
- FreeBSD: requires the `acpi_video(4)` loaded,
- OpenBSD.

Installation on Linux

First, build the program:


On Linux, adjusting the brightness can be done as normal user if you have write
access to the appropriate files which are usually under */sys*.

The recommandation is to install the udev rule which change the ownership of the
brightness file to `video` group and writable by users in this group. Use the
`install-udev` for that purpose. Then don't forget to check if you are part of
the video group.

	make install
	make install-udev

Otherwise, as alternative you can simply install the binary as setuid if you
don't run udev.

	make install-setuid

Installation on FreeBSD

In FreeBSD, it's required to have the tool in setuid as there is no way to
change sysctl values from a regular user.

Also, you will need the ACPI video module, add the following to your


Alternatively, you can compile this module into the kernel.

Then install using:

	make install-setuid