Backlight: Difference between revisions
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== Introduction == | == Introduction == | ||
This page documents methods for | This page documents methods for controlling backlight (aka screen brightness) and tips to control it via hotkeys. | ||
== <code>xbacklight</code> == | == <code>xbacklight</code> == | ||
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<code>xbacklight</code> uses X to change the light settings. This can be inconvenient in some situations, e.g. for use with the {{nixos:option|services.actkbd}} service, which doesn't know about the X session. It, though, has an history of being more compatible with different hardware, especially newer hardware<sup>[citation needed]</sup> | <code>xbacklight</code> uses X to change the light settings. This can be inconvenient in some situations, e.g. for use with the {{nixos:option|services.actkbd}} service, which doesn't know about the X session. It, though, has an history of being more compatible with different hardware, especially newer hardware<sup>[citation needed]</sup> | ||
To | To install <code>xbacklight</code> globally, add this to your <tt>configuration.nix</tt>. | ||
< | <syntaxhighlight lang=nix> | ||
environment.systemPackages = with pkgs; [ xorg.xbacklight ]; | |||
</syntaxhighlight> | |||
Alternatively, use <code>nix-env -iA nixos.xorg.xbacklight</code> to install it to your user profile. | |||
== <code>light</code> == | == <code>light</code> == | ||
<code>light</code> does not use X to change the light settings. This can be used in situations where the X service isn't available.</code> | <code>light</code> does not use X to change the light settings. This can be used in situations where the X service isn't available. While it does not use X, it will need some privileges to work. This means that it needs to either be installed in a specific way (with a SUID wrapper) or used using <code>sudo</code>, or ran with superuser privileges. | ||
To enable the use of <code>light</code> with SUID wrappers, add this to your <tt>configuration.nix</tt>. | |||
<syntaxhighlight lang=nix> | |||
programs.light.enable = true; | |||
</syntaxhighlight> | |||
The following commands will allow you to test <code>light</code>: | |||
<code> | *<code>light -U 30</code> — the screen should become darker. | ||
*<code>light -A 30</code> — the screen should become brighter. | |||
Be careful using <code>light -U</code>, as you might turn your backlight completely off! You will not be able to see what you're typing anymore. | |||
== Tips == | |||
== Key mapping == | === Key mapping === | ||
Once the backend functionality of controlling the backlight is verified, you can assign that to an actual key. Different laptops and keyboards may map the hotkeys to different key codes. | Once the backend functionality of controlling the backlight is verified, you can assign that to an actual key. Different laptops and keyboards may map the hotkeys to different key codes. | ||
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};</syntaxhighlight> | };</syntaxhighlight> | ||
Tested with NixOS 18.03, and in combination with lightdm & i3. | Tested with NixOS 18.03, and in combination with lightdm & i3. | ||
== See also == | == See also == | ||
* [https://wiki.archlinux.org/index.php/backlight Arch Linux wiki page about the backlight] | * [https://wiki.archlinux.org/index.php/backlight Arch Linux wiki page about the backlight] |