I found a problem on kubuntu. If I am currently in the wayland environment and have a wayland qt application now, and set QT_QPA_PLATFORM=wayland in the program, then when the system logs out, The logic of the program is that applications that support the xsmp protocol will normally follow the xsmp protocol process, but wayland applications cannot. Therefore, it can only notify and close the window through Wayland’s own protocol at the end. So I have a question. Since both the desktop and the taskbar support xsmp, but Wayland applications do not, Could this cause the desktop and taskbar to exit, while the Wayland application is still displayed on the desktop, resulting in a phenomenon where the desktop is black and Wayland is still on the black screen? I wonder if there is any solution to this problem.
Hi - sorry, I’m having a bit of trouble following what’s happening on your device from the description above. Could you perhaps list out the steps that you’re taking, then what you observe happening? For example:
- Open application A
- Open application B
- Click Application Launcher then Log Out
- Observed: <description of what’s on your screen at that moment>
Could you also please provide your basic system information from the Info Center app? The Copy Details button is the easiest way to get that ready to paste in:
Thanks!
Thank you very much for your reply. I put the relevant information of the system below. I didn’t have this problem on kubuntu, but I read the source code of kde, so I have some questions about it. In the source code, my understanding is that the application that registers with the xsmp protocol first in the process of logging out will receive a shutdown notification first, and in these applications that receive xsmp notifications Including the desktop and the taskbar, and finally the wayland application receives a notification to close the window, of course, the premise is that it needs to be in the wayland environment. So I have a question here. Under such logic, will there be a situation where the desktop and the taskbar will be exited first, and the wayland application will not have time to exit in the future, and the Wayland application will appear on the black screen for a moment. I don’t know if I understand that there are some problems. The source code I read is the call of closeWaylandWindows () in ksmserver/server.cpp and kwin’s sm.cpp.
Operating System: Kubuntu 24.10
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.6.2
Kernel Version: 6.11.0-24-generic (64-bit)
Graphics Platform: Wayland
Processors: 12 × Intel® Core™ i5-10500 CPU @ 3.10GHz
Memory: 7.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 630
Manufacturer: Dell Inc.
Product Name: OptiPlex 3080
I think I’ll have to defer to folks more experienced with navigating the KWin source code to dive further into that one 
Well, thank you for your reply.