Backlight remains on after automatic screen blank

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1

I am running Fedora 41 with Gnome 47 & Wayland on a Lenovo Yoga Slim 7 Pro laptop with Ryzen 5800H. When the screen blanks out due to inactivity, the screen and keyboard backlights turn off but then immediately the screen backlight turns back on again despite the screen being black. This is unaffected by having dimming due to inactivity on or off before it blanks.

However, if I manually lock the screen with Super+L or I suspend the laptop, then the screen backlight is off as it should be.

What could be going wrong? How to ensure the backlight remains off after an automatic screen blank?
Many thanks

2

Hii I’ve come from the dark side of Debian :smiling_face_with_horns: to register my +1 me too for this issue as well. :face_with_tongue:

It’s been going on some months I think, since you posted at least. Did it start for you in Feb or before then? Are you still having the issue? I don’t think it’s always been the case but after a while I become numb to some bugs.

I’m on some Debian version 13ish testing/trixie
Linux 6.12.21-amd64 Debian 6.12.21-1 (2025-03-30) x86_64 GNU/Linux
GNOME 48.0 / X11
Lenovo ThinkPad X1 Carbon 4th :raised_hand:

Oh my god the power related issues in a laptop running Linux are never ending :upside_down_face: You get one thing working then another pops up. but that’s ok somethin needs to keep me on my toes ig

3

I’ve seen my external display do that randomly usually when trying different stuff under GNOME and Xfce Xorg (intel/modesetting DDX stuff).

I’m not sure what causes it, but if you have any GPU-related custom xorg.conf snippets I’d remove them and default to modesetting. There may be something if you’ve installed Intel’s or amdgpu Xorg DDX too (uninstall em so modesetting is used).

I haven’t seen it happen under GNOME on Wayland.

4

Thanks sir! Hmmm I do have this:
/etc/X11/xorg.conf.d/20-intel.conf:

Section "Device"
    Identifier "Intel Graphics"
    Driver "intel"
    Option "AccelMethod" "sna"  # Try "sna" or "uxa" if needed (see below)
    Option "DRI" "3"           # Try DRI 2 or 3 if needed (see below)
        Option "TearFree" "true"
EndSection

Section "Screen"
    Identifier "Default Screen"
    Device "Intel Graphics"
EndSection

I’ll look into where that came from and see about uninstalling it and reverting back to modesetting.

Not sure if it’s relevant but I also have an external display connected to HDMI.

and I did have an observation to share:

  • If I lock the screen manually with meta+L: It pulls down the lock screen shade with date and time and then immediately blanks and shuts off the display.
  • On the other paw, if i let it sit for the idle timeout period: the desktop will slowly fade to black :sign_of_the_horns: then kind of just sits there without turning off.

Since those appear to be 2 distinct operations, I was thinking there are different scripts or commands involved. Anyone know where the code for that lives?