Public bug reported:
I have a Dell Precision 5680 laptop that's equipped with an ambient
brightness sensor, that GNOME can use to automatically adjust the screen
brightness.
However, I generally want my display to have a lower brightness to
maximize battery life, and I find brightness changes to be distracting,
so I've disabled this functionality within GNOME my session, like so:
Within the "Settings" application: Power > Power Saving > Automatic
Screen Brightness: Toggled "off"
Within this configuration, I have manual brightness control, as
expected.
However, when I am at the GNOME login screen, I can still see the
characteristic brightness changes that I would expect when automatic
screen brightness is enabled. I don't see any obvious way to disable
this, and when I check the brightness settings in the GNOME login
screen, it is set to the level I had configured (even though the screen
is obviously much brighter than what the setting suggests).
When I log in to my session, my brightness is much higher than expected
(and what I had set it to), both physically, and with respect to the
brightness setting. I can decrease the brightness again and it stays
there for the duration of my session.
I don't recall having to adjust the brightness settings in this way when
running Ubuntu 24.04, although I don't have a similarly-equipped machine
where I can actually test this.
----
Expected behavior:
When I disable automatic screen brightness and manually set my brightness, I
expect that to either be applied to GNOME login manager as well, -OR- I expect
my session to restore the brightness settings that I had previously when I log
in.
Actual behavior:
The GNOME login manager has its own brightness settings (and appears to be
using automatic screen brightness), which overrides what I had set in my
session, leaving me to have to adjust the brightness of my screen each time I
log in.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: gdm3 50.0-0ubuntu1
ProcVersionSignature: Ubuntu 7.0.0-10.10-generic 7.0.0-rc4
Uname: Linux 7.0.0-10-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.33.1-0ubuntu7
Architecture: amd64
CasperMD5CheckMismatches: ./boot/grub/i386-pc/eltorito.img
CasperMD5CheckResult: fail
CurrentDesktop: ubuntu:GNOME
Date: Mon Apr 6 09:50:28 2026
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: gdm3 (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2147357
Title:
Brightness settings from GNOME login manager override GNOME session
brightness settings
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