Bug#1113751: kwin-x11 high cpu usage when screen is locked
Hi Jared,
On Mon, 01 Sep 2025 22:03:25 -0600 Jared Epp <jaredepp@pm.me> wrote:
> Source: kwin
> Severity: normal
> X-Debbugs-Cc: jaredepp@pm.me
>
> Dear Maintainer,
>
> Since upgrading from Bookworm to Trixie, when I lock my screen,
> kwin_x11 maxes out one CPU core. Most of the CPU usage goes to
> kwin_x11 but some goes to Xorg and a little to ksmserver.
>
> I found this bug report upstream and it seems to be the same as my
> issue https://bugs.kde.org/show_bug.cgi?id=484323
>
> The workaround of using systemctl --user restart plasma-
> kwin_x11.service (via ssh) after locking the screen was effective for
> me, as well as going to System Settings > Display and Monitor
> Compositor and unchecking Enable on Startup.
>
> It seems like the bug actually comes from Qt and was fixed here
> https://codereview.qt-project.org/c/qt/qtbase/+/663811
You're right, the bug is actually in qt6-base and was reported here:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1111957
I'll try to backport this to trixie.
--
Med vänliga hälsningar
Patrick Franz
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