Public bug reported:
Subject: All-in-one PC F+ FMB-270-P1 display backlight turns off after 1
second of static image (Ubuntu 26.04 / Wayland / Mutter)
Description:
On an F+ FMB-270-P1 AIO computer (Intel Core 12th Gen, Intel UHD 730), the
screen backlight completely turns off exactly 1 second after login or whenever
the screen display becomes static.
The screen remains active ONLY if there is a constantly updating element
on the screen, such as a blinking cursor in the Terminal or a text input
cursor in a web browser.
This happens because the Wayland compositor / GNOME Mutter aggressively
throttles the frame rate to 0 on static images (Frame Rate Throttling).
The AIO monitor's controller misinterprets this lack of frame updates as
a hardware sleep command and cuts the backlight power. The hardware is
fully functional under Windows 10/11.
Kernel parameters like i915.enable_psr=0, xe.enable_psr=0, and
intel_idle.max_cstate=1 DO NOT fix the problem.
The only working workaround is forcing continuous frame updates by
running a hidden 1x1 pixel micro-animation in the background via
autostart: "glxgears -geometry 1x1-100-100".
Please consider disabling frame rate throttling / PSR by default for
this specific hardware configuration or add an option to override this
behavior in GNOME.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: mutter (not installed)
ProcVersionSignature: Ubuntu 7.0.0-22.22-generic 7.0.0
Uname: Linux 7.0.0-22-generic x86_64
ApportVersion: 2.34.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Fri Jun 19 23:29:23 2026
InstallationDate: Installed on 2026-06-17 (2 days ago)
InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
ProcEnviron:
LANG=ru_RU.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: mutter (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2157667
Title:
All-in-one PC F+ FMB-270-P1 display backlight turns off after 1 second
of static image
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