Xfce Forum

doodloo

Member

From: London

Registered: 2015-09-11

Posts: 51

[SOLVED] Problems with Xubuntu 20.10

Good evening,

I've installed Xubuntu 20.10 today, and there are a few things that don't work as expected. One of them seems to be related with Xubuntu.
The brightness keys of my laptop don't work any more - even though the "brightness notifications" change appear properly when pressing them.

When adjusting the brightness via command line (Eg. `xrandr --output DP-2 --brightness 0.5`) it seems to be adjusting some form of software brightness, but the physical light behind the LCD panel doesn't really seem to change.

EDIT: After closer inspection, it seems that there's a change in behaviour with the graphics driver (nvidia proprietary). With the same versions (450 and 455) of the driver as I was using before I'm not offered the choice between integrated and discrete graphics - and when using the Nouveau driver, the brightness works...

Any idea please?

Thanks,
Doodloo.

Last edited by doodloo (2021-01-03 11:47:17)

doodloo

Member

From: London

Registered: 2015-09-11

Posts: 51

Re: [SOLVED] Problems with Xubuntu 20.10

Bumpidy bump?

ToZ

Moderator

From: Canada

Registered: 2011-06-02

Posts: 7,281

Re: [SOLVED] Problems with Xubuntu 20.10

This is probably more related to the kernel and the video driver than Xfce.

As per https://forums.developer.nvidia.com/t/l … ode/160292. does creating the file /etc/X11/xorg.conf.d/21-nvidia-brightness.conf with the contents:

Section "OutputClass"
    Identifier "nvidia"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection

...and rebooting help?

---

How To Ask For Help  |  FAQ  |  Release Info  |  Community  |  Contribute

alcornoqui

Member

Registered: 2014-07-28

Posts: 781

Re: [SOLVED] Problems with Xubuntu 20.10

And if that doesn't work, maybe take a look at Ubuntu's wiki on backlight troubleshooting and report back.

Good luck!

doodloo

Member

From: London

Registered: 2015-09-11

Posts: 51

Re: [SOLVED] Problems with Xubuntu 20.10

Guys, thanks a lot for taking the time. This is very valuable information, and I didn't try any of this yet.
I will report back tomorrow once I have tried.

Thanks again!

doodloo

Member

From: London

Registered: 2015-09-11

Posts: 51

Re: [SOLVED] Problems with Xubuntu 20.10

Hello again Alcornoqui and ToZ,

I just gave a quick try to ToZ's solution first, and it worked.
Just a few notes for anyone who might be in the same situation:
- On my distribution, `/etc/X11/` did not contain a `xorg.conf.d` folder. I had to create it.
- Interestingly, `/etc/X11` also doesn't contain a `xorg.conf` file. Maybe that's the main difference between before and now. I didn't have to create one.

If you're unsure, here are the steps to do what ToZ suggested:

sudo mkdir -p /etc/X11/xorg.conf.d
sudo touch /etc/X11/xorg.conf.d/21-nvidia-brightness.conf
sudo vim /etc/X11/xorg.conf.d/21-nvidia-brightness.conf
# At this point, copy-paste ToZ's snippet in your editor - save the file and reboot.

Thanks a lot guys.

Last edited by doodloo (2021-01-03 11:46:57)