Public bug reported:
Package / Release:
Package: gnome-shell
Version: 50.1-0ubuntu1.2
Release: Ubuntu 26.04 (development/current)
Session type: Wayland
Environment:
GNOME Shell: 50.1-0ubuntu1.2
gnome-settings-daemon: 50.0-1ubuntu1
Session: Wayland
Displays (extended, two monitors on two different GPUs):
- eDP-1 1920x1080 (internal panel, AMD iGPU / card1)
- HDMI-A-1 2560x1700 (external monitor, NVIDIA / card2)
GPU: NVIDIA RTX 4060 Laptop (driver 595.91.07) + AMD Radeon iGPU
Description:
With the built-in break reminders feature configured for the "eyesight"
break and screen fading enabled, starting a break dims the primary
monitor correctly, but the secondary monitor flashes white rapidly and
continuously for the whole duration of the break. The flashing is very
bright and fast (multiple flashes per second) and makes the second
screen unusable until the break ends.
The primary (internal eDP-1) monitor behaves correctly and just dims.
Only the non-primary output (HDMI-A-1) misbehaves.
Note the two outputs are driven by two different GPUs/DRM devices
(AMD iGPU for eDP-1, NVIDIA for HDMI-A-1), which may be relevant to how
the break-dimming overlay surface is composited per-output.
Steps to reproduce:
1. On a system with two monitors in extended mode, enable the built-in
break reminders for the "eyesight" break with screen fading on:
gsettings set org.gnome.desktop.break-reminders selected-breaks
"['eyesight']"
gsettings set org.gnome.desktop.break-reminders.eyesight fade-screen
true
gsettings set org.gnome.desktop.break-reminders.eyesight
interval-seconds 1200 # 20 min
gsettings set org.gnome.desktop.break-reminders.eyesight
duration-seconds 20 # 20 s
2. Wait for a break to trigger (or trigger one), so the screen fade
starts.
3. Observe the primary monitor dimming normally while the secondary
monitor flashes white rapidly/continuously.
Expected behavior:
All connected monitors dim (or the break overlay draws) smoothly and
uniformly; no flashing on any output.
Actual behavior:
Secondary monitor (HDMI-A-1, driven by a different GPU than the primary)
flashes white wildly/continuously while the primary monitor dims for the
break. The system remains responsive; only the rendering on the
secondary output is broken.
Current break-reminder settings on the affected system:
org.gnome.desktop.break-reminders.eyesight:
fade-screen = true
interval-seconds = 1200
duration-seconds = 20
delay-seconds = 120
countdown = false
lock-screen = false
notify = true
notify-overdue = true
notify-upcoming = false
play-sound = true
org.gnome.desktop.break-reminders.selected-breaks = ['eyesight']
Workaround:
Disabling the screen fade avoids the flashing (the reminder still shows
its notification and chime, it just no longer dims):
gsettings set org.gnome.desktop.break-reminders.eyesight fade-screen false
Possible cause / hint for maintainers:
The break "fade-screen" dimming overlay appears to be created/tracked
for the primary monitor only, or is composited with the wrong
alpha/format on the non-primary output, producing a full-white surface
on the secondary monitor. Multi-monitor with outputs on separate DRM
devices reproduces it reliably.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: gnome-shell 50.1-0ubuntu1.2
ProcVersionSignature: Ubuntu 7.0.0-31.31-generic 7.0.14
Uname: Linux 7.0.0-31-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu Sep 24 11:08:29 2026
DisplayManager: gdm3
InstallationDate: Installed on 2026-08-31 (24 days ago)
InstallationMedia: Ubuntu 26.04.1 LTS "Resolute Raccoon" - Release amd64
(20260826)
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/usr/bin/zsh
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
RebootRequiredPkgs: Error: path contained symlinks.
RelatedPackageVersions: mutter-common 50.1-0ubuntu2.4
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.apport.crashdb.conf: [modified]
mtime.conffile..etc.apport.crashdb.conf: 2026-09-18T23:33:30.043753
** Affects: gnome-shell (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2168466
Title:
Break reminder "eyesight" fade-screen makes secondary monitor flash
white when primary dims (multi-monitor, Wayland)
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2168466/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
