SUMMARY I'm using X11 forwarding via SSH to run some applications on a remote system and interact with them on my local system, which is running a Wayland session. Every couple of seconds when interacting with the forwarded application, my entire screen freezes for 3 seconds or so. This makes X11 forwarding extremely tedious to use in the wayland session. I don't see any relevant messages about this in the journal. STEPS TO REPRODUCE 1. While in a Wayland session, connect to a remote system via SSH with X11 forwarding enabled 2. Run any graphical application on the remote host so that it displays on your local machine 3. Interact with the window OBSERVED RESULT The whole screen freezes regularly for several seconds. EXPECTED RESULT Everything should be smooth, at most the forwarded Xwayland window should freeze but not the whole desktop SOFTWARE/OS VERSIONS Operating System: Fedora Linux 40 KDE Plasma Version: 6.0.5 KDE Frameworks Version: 6.2.0 Qt Version: 6.7.0 Kernel Version: 6.8.10-300.fc40.x86_64 (64-bit) Graphics Platform: Wayland Processors: 20 × 12th Gen Intel® Core™ i7-12700H Memory: 15.3 GiB of RAM Graphics Processor: Mesa Intel® Graphics ADDITIONAL INFORMATION I tried to run Nautilus, Firefox and Virtualbox via SSH X11 forwarding on a Debian 12 server and observed the same behavior with all of them. I have no such problems when using Waypipe but unfortunately at least VirtualBox needs X11.
Same problem here on the plasma 6.1.4. When I forward xwayland socket /tmp/.X11-unix/X0 to the incus contaner (example ubuntu 22.04) and set Xauth token, when interaction with the opened X11 application from this container freezes entire plasma session for the a few seconds.
Can you get kwin_wayland's backtrace when the screen is frozen? You would need to SSH from another machine and attach a debugger to kwin_wayland process. https://community.kde.org/KWin/Debugging
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Created attachment 174262 [details] backtrace after freeze Attached backtrace after freeze happened. Sorry, I don't familiar with gdb and do steps only from https://community.kde.org/KWin/Debugging#TL;DR_for_bug_reporters. If that backtrace doesn't help, please clarify what should I do, thanks.
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🐛🧹 This bug has been in NEEDSINFO status with no change for at least 30 days. Closing as RESOLVED WORKSFORME.
Sorry for not responding in such a long time but I finally got around to trying to get a backtrace, however I can no longer reproduce this issue on any system (with Intel, AMD or VirtIO graphics) on Plasma 6.2. I still recommend using Waypipe instead of X11 forwarding whenever possible since it performs a million times better but at least X11 forwarding is a usable option now.