You are not logged in.

#1 2021-12-05 18:50:49

Registered: 2015-06-30
Posts: 5

Screen flicker with brightnessctl key, not from terminal

Hello. I have an issue with my laptop when using the keyboard to decrease screen brightness.

This is a Dell XPS L501x with an Nvidia GeForce 420M (Optimus) using nvidia drivers + Bumblebee, in case that's relevant (but I suspect it's not). I'm running Qtile as my window manager.

When I use

brightnessctl set 10%-

from the terminal, everything works as expected: I can see the brightness decreasing by 10% with no weirdness at all.

However, when I use the XF86MonBrightnessDown key to run the exact same command through my Qtile key binding, I can see a very short and bright white flicker and then the brightness goes to the desired setting.

Here's my Qtile key binding for screen brightness:

keys = [Key(key[0], key[1], *key[2:]) for key in [
# Brightness
    ([], "XF86MonBrightnessUp", lazy.spawn("brightnessctl set +10%")),
    ([], "XF86MonBrightnessDown", lazy.spawn("brightnessctl set 10%-")),

I'd like to know why this happens with the Qtile key binding and not when running that same command from the terminal, and I'd like to find a way to make it work as expected.

Additionally, I should mention that this flicker doesn't happen with the XF86MonBrightnessUp key binding for

brightnessctl set +10%


Thanks for your support!

Edit: I don't know if the whole Nvidia Optimus thing is at play here, but just to clarify, when I run the command from the terminal, I'm using alacritty with the Nvidia GPU through

optirun alacritty

I don't know if this could influence the way that brightnessctl is working.

Last edited by Acente (2021-12-05 18:53:48)


#2 2022-01-06 20:02:01

Registered: 2015-06-30
Posts: 5

Re: Screen flicker with brightnessctl key, not from terminal

Apparently this isn't a Qtile issue, I was able to reproduce the same condition in XFCE and i3 WM in Arch. I've also tested the command in xterm (without optirun) instead of Alacritty, and everything works fine, so it doesn't seem like it's related to the whole Nvidia Optimus situation. I submitted issues to the brightnessctl github and will keep posting updates here.


Board footer

Powered by FluxBB