Thanks for the suggestion. I indeed had a manually installed driver from a few years ago before Ubuntu had official support for my GPU. Uninstalling the old driver solved the issue.
On Thu, May 21, 2026 at 5:50 AM Jonas Eigemann <[email protected]> wrote: > I had the same bug after updating Kubuntu from 25.10 to 26.04 LTS. > For me, completely removing and then reinstalling the amdgpu driver > package with the latest version solved the issue. > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/2152794 > > Title: > Opening the KDE displays system menu gives an error of "No KScreen > backend found." > > Status in kscreen package in Ubuntu: > New > > Bug description: > System release version: > Description: Ubuntu 26.04 LTS > Release: 26.04 > > Package Version Policies: > kscreen: > Installed: 4:6.6.4-0ubuntu1 > Candidate: 4:6.6.4-0ubuntu1 > Version table: > *** 4:6.6.4-0ubuntu1 500 > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe amd64 > Packages > 100 /var/lib/dpkg/status > libkscreen-bin: > Installed: 4:6.6.4-0ubuntu1 > Candidate: 4:6.6.4-0ubuntu1 > Version table: > *** 4:6.6.4-0ubuntu1 500 > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe amd64 > Packages > 100 /var/lib/dpkg/status > libkscreen-data: > Installed: 4:6.6.4-0ubuntu1 > Candidate: 4:6.6.4-0ubuntu1 > Version table: > *** 4:6.6.4-0ubuntu1 500 > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe amd64 > Packages > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe i386 > Packages > 100 /var/lib/dpkg/status > libkf6screen8: > Installed: 4:6.6.4-0ubuntu1 > Candidate: 4:6.6.4-0ubuntu1 > Version table: > *** 4:6.6.4-0ubuntu1 500 > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe amd64 > Packages > 100 /var/lib/dpkg/status > kwin-wayland: > Installed: 4:6.6.4-0ubuntu1 > Candidate: 4:6.6.4-0ubuntu1 > Version table: > *** 4:6.6.4-0ubuntu1 500 > 500 http://us.archive.ubuntu.com/ubuntu resolute/universe amd64 > Packages > 100 /var/lib/dpkg/status > > > When did this start: > - After I upgraded from Kubuntu 25.10 to Kubuntu 26.04 > > What I expect to happen: > - The system menu to load the display settings. > > What happens instead: > - System menu shows red error alert with the text "No KScreen backend > found. Please check your KScreen installation." > > What I've tried/checked: > > - Reinstalling kscreen > > - Regenerating ~/.config/kwinoutputconfig.json > > - Running with KSCREEN_BACKEND_INPROCESS=1 > > - Cleared my ~/.cache and ~/.config > > - Create a new system user > > - Disabling bluedevil (An arch thread found a bluedevil loading error > blocked the kscreen backend from loading) > > - Found no missing shared library dependencies (ldd clean on all .so > files). > > - Found backend plugins exist at /usr/lib/x86_64-linux- > gnu/qt6/plugins/kf6/kscreen/ (KSC_KWayland.so, KSC_XRandR.so, > KSC_Fake.so). > > - kscreen-doctor --info finds all three KScreen backends. But > defaulted to XRandR. Creating /etc/xdg/kscreenrc with > PreferredBackend=KSC_KWayland fixed the selection, but did not resolve > the issue. > > - kscreen-console returns empty config. kscreen-console json returns > {} after 1-2ms. kscreen-console outputs says "Config is invalid, > probably backend couldn't load." kscreen-console bug displays valid > monitor data but this is read from ~/.config/kwinoutputconfig.json, > not from the live backend. > > - KWin is functioning correctly. kwin_wayland --version reports 6.6.4. > Information shows both outputs enabled with correct geometry. wayland- > info confirms kde_output_management_v2 (v19) and two > kde_output_device_v2 (v20) interfaces are advertised. > > ProblemType: Bug > DistroRelease: Ubuntu 26.04 > Package: kscreen 4:6.6.4-0ubuntu1 > ProcVersionSignature: Ubuntu 7.0.0-15.15-generic 7.0.0 > Uname: Linux 7.0.0-15-generic x86_64 > ApportVersion: 2.34.0-0ubuntu2 > Architecture: amd64 > CasperMD5CheckResult: unknown > CurrentDesktop: KDE > Date: Sat May 16 11:09:41 2026 > InstallationDate: Installed on 2024-05-27 (719 days ago) > InstallationMedia: Kubuntu 23.10 "Mantic Minotaur" - Release amd64 > (20231010) > SourcePackage: kscreen > UpgradeStatus: Upgraded to resolute on 2026-05-15 (1 days ago) > > To manage notifications about this bug go to: > > https://bugs.launchpad.net/ubuntu/+source/kscreen/+bug/2152794/+subscriptions > > -- You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to kscreen in Ubuntu. https://bugs.launchpad.net/bugs/2152794 Title: Opening the KDE displays system menu gives an error of "No KScreen backend found." To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kscreen/+bug/2152794/+subscriptions -- kubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs
