How To Control Brightness On External Monitor

Support Graphics & Display
1

Hello,

Background:
I have a Dell XPS 9350 connected to a Dell External monitor over USB-C. I am running Wayland and Gnome 42.

As the subject states, looking for a brightness app / extension that can control my External Monitor. I currently have a laptop with an external monitor connected (over USB-C), and the default brightness app only controls the monitor internal display.

Question:
What is the easiest way to control the brightness of the external monitor?

I tried the following application, but it did not work for me:

Any assistance would be greatly appreciated. Thanks!

2

Hi @A4orce84,

I don’t at all know if this is what you’re looking for, if it’ll work, or anything else for that matter, so if it’s not what you’re looking for…:man_shrugging:

It would seem, however, as if brightness-controller is in the AUR:

$ pamac search brightness-controller
[...]
brightness-controller-git                                                                                                                                                                                                         2.3.4.r286.ea7434a-2  AUR
Control Brightness of your Primary and Secondary Display in Linux

So it can be installed using:

pamac build brightness-controller-git

Hope this helps!

3

Yup, I installed it and the application window launches. However, adjusting any of the actual brightness settings does not DO anything on my system.

4

Have you tried launching it from the terminal and see is there are any errors?

Edit:

According to you link:

This all works via xrandr, so if you’re using a Wayland session this app, alas, won’t work.

So, it’ll not work for you since you use Wayland.

However, I have found some alternatives:

Screen Dimmer, which is in the AUR:

$ pamac search dimmer
[...]
screendimmer                                                                                                                                                                                                                                   0.4.2-1  AUR 
A tray application to dim your monitor brightness.
[...]

It can be installed with:

pamac build screendimmer

As well as desktop-dimmer, also in the AUR:

$ pamac search dimmer
[...]
desktop-dimmer                                                                                                                                                                                                                                 4.0.4-2  AUR 
Enables darker-than-dark Desktop dimming for your displays.

So, it can be installed using:

pamac build desktop-dimmer

Or dim-screen, also in the AUR:

$ pamac search dimmer
dim-screen                                                                                                                                                                                                                                     1.0-1    AUR 
A screen dimmer bash script designed to work with xss-lock
[...]

So, can be installed using:

pamac build dim-screen

However, I don’t use Wayland, so can’t know.

:man_shrugging:

5

Terminal output:

~  brightness-controller                                                                                                        ✔ 
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
6

Try starting it with:

QT_QPA_PLATFORM=wayland brightness-controller

But, as I said, Wayland is not supported, so it might not even probably won’t work.

7

For me ddcutil works well. It is a command utility but that should not scare a Manjaro user.
ddcutil gives commands to the monitor directly, don’t know if it works through usb-c though.

8

Try vdu_controls available in the AUR.

9

I use xrandr. It works, but it is tricky to set with login script. I had to use a sleep 32 command before xrandr in the little script I created.

Here is my sample xrandr command, with VGA-1 being the external monitor. I have the laptop screen pumped up on the gamma in the KDE gamma settings and so to compensate I had to lower the gamma output on the external display. You could start with values of 1 for red, blue and green and experiment from there.

/usr/bin/xrandr --output VGA-1 --gamma .45:.50:.60

10

xrandr doesn’t work with Wayland, IIRC, so is no use here and won’t work. But see

Perhaps that helps!

1 Like
11

The xrandr method is a work around, and not a perfect one. I hope KDE will SOON offer gamma tweaking to individual monitors on dual monitor setups.