On Debian 13 Stable running KDE Plasma Wayland, KWin exhibits the following issue:
-
A single flickering inconsistent vertical line on the side of the main screen when using an external lcd connected via usb-c display port. While using fractional scaling on the main screen, at an interval that is not a multiple of 50%, such as 175% or 125%.
Steps to reproduce
-
Log in to a Plasma Wayland session from SDDM.
- Plug in or already have an external lcd plugged in via usb-c display port, have main (laptop) display set to use fractional scaling, at an interval such as 175% or 125%
-
Open any window with a light/white color on dark background, on the main (laptop) display.
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Move window across edge of screen and/or move mouse around on main screen.
Expected result
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No artifacts
Actual result
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An inconsistent vertical line, opposite the external display, for example, if the external is mapped to the left of the main display, the vertical will show up on the right side of the main display. It appears to show pixel artifacts from dragging a window over it, and then flicker when the mouse or white content on a window is moved.
-
Video attached demonstrating artifacts.
Frequency
-
Always happen
System Information:
Debian Release: 13.3
APT prefers stable
APT policy: (700, 'stable'), (500, 'stable-updates'), (500, 'stable-security')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 6.17.8+deb14-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages kwin-wayland depends on:
ii libc6 2.41-12+deb13u1
ii libcanberra0 0.30-18
ii libcap2-bin 1:2.75-10+b3
ii libepoxy0 1.5.10-2
ii libkdecorations3-6 4:6.3.4-1
ii libkf6configcore6 6.13.0-2
ii libkf6configgui6 6.13.0-2
ii libkf6configwidgets6 6.13.0-1
ii libkf6coreaddons6 6.13.0-1
ii libkf6crash6 6.13.0-1
ii libkf6dbusaddons6 6.13.0-1
ii libkf6globalaccel6 6.13.0-1
ii libkf6i18n6 6.13.0-1
ii libkf6idletime6 6.13.0-1
ii libkf6notifications6 6.13.0-1
ii libkf6service-bin 6.13.0-1
ii libkf6service6 6.13.0-1
ii libkf6svg6 6.13.0-1
ii libkf6windowsystem6 6.13.0-2
ii libkglobalacceld0 6.3.6-1
ii libkwin6 4:6.3.6-1
ii libqaccessibilityclient-qt6-0 0.6.0-3
ii libqt6core6t64 [qt6-base-private-abi] 6.8.2+dfsg-9+deb13u1
ii libqt6dbus6 6.8.2+dfsg-9+deb13u1
ii libqt6gui6 6.8.2+dfsg-9+deb13u1
ii libqt6qml6 6.8.2+dfsg-7
ii libqt6quick6 6.8.2+dfsg-7
ii libqt6widgets6 6.8.2+dfsg-9+deb13u1
ii libstdc++6 15.2.0-7
ii libsystemd0 257.9-1~deb13u1
ii libxcb-composite0 1.17.0-2+b1
ii libxcb-randr0 1.17.0-2+b1
ii libxcb-xfixes0 1.17.0-2+b1
ii libxcb1 1.17.0-2+b1
ii xwayland 2:24.1.6-1
Versions of packages kwin-wayland recommends:
ii xwaylandvideobridge 0.4.0-2+b1
kwin-wayland suggests no packages.