Created attachment 184578 [details] journalctl Severe performance lag on DisplayLink USB monitor under KDE Wayland due to framebuffer creation errors. STEPS TO REPRODUCE Connect a DisplayLink USB monitor to a system running KDE Plasma on a Wayland session. Observe the performance of the display (e.g., moving a window, scrolling in a browser). OBSERVED RESULT The display output is extremely laggy, with a very low refresh rate and high latency, making the monitor nearly unusable. The system journal shows a continuous error: kwin_wayland_drm: Failed to create a framebuffer: Invalid argument. The evdi kernel module is loaded and the displaylink.service is active. EXPECTED RESULT Performance should be adequate for basic desktop tasks, comparable to the experience on an X11 session or Windows, utilizing hardware acceleration. SOFTWARE/OS VERSIONS Linux/KDE Plasma: CachyOS KDE Plasma Version: 6.4.4 KDE Frameworks Version: 6.17.0 Qt Version: 6.9.1 ADDITIONAL INFORMATION The same hardware functions correctly on a Plasma X11 session and Windows, proving it is a software integration issue specific to Wayland. The journal is flooded with the framebuffer error. The full log output from journalctl -b -0 -g "displaylink|evdi|kwin" --no-pager is attached. This is distinct from other reported issues about fullscreen compositing (e.g., bug #XXXXX). This bug occurs globally on the DisplayLink monitor and is triggered by the presence of the device itself, not by entering fullscreen. Attachments: kwin_displaylog_log.txt, system_info.txt
Created attachment 184579 [details] system_info
Created attachment 184580 [details] us_navy_edid.bin