Created attachment 105323 [details] Backtrace of one such crash. when I select the plasma wayland session, I get a black screen for a second or two, but then get returned to the DM (SDDM). The logs mention that kwin_wayland has crashed (with messages like the following) May 03 15:07:23 arch-testing systemd-coredump[738]: Process 736 (kwin_wayland) of user 1001 dumped core. I have attached a backtrace.
Unfortuntely the debug symbols for Qt are missing and it crashes directly when creating the QApplication. Given the information we have from it: do you have the KWin QPA plugin installed to the correct location so that Qt finds it?
(In reply to Martin Gräßlin from comment #1) > Given the information we have from it: do > you have the KWin QPA plugin installed to the correct location so that Qt > finds it? How can I check if I have it? I'm not sure if this is related, but when I type 'kwin_wayland --version', I get the following output: kwin_wayland --version This application failed to start because it could not find or load the Qt platform plugin "wayland-org.kde.kwin.qpa" in "". Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb. Reinstalling the application may fix this problem. fish: “kwin_wayland --version” terminated by signal SIGABRT (Abort) However, typing 'kwin_x11 --version' gives just the application name and version number as expected.
On further digging, I found that this happens when I'm using qt 5.9 beta 3. Using qt 5.8, the wayland session launches normally.
Created attachment 105334 [details] Backtrace with debug symbols for Qt I have attached a backtrace generated after installing qt with debug symbols.
Changing to invalid as KWin must be run against the Qt version it was compiled with.