When I log out of my Wayland session with the Hyprland compositor, I get a black screen with a flashing cursor, but can’t type anything. I then have to reboot, and only then does SDDM work as expected, albeit with a few seconds delay.
I Have reproduced the error several times using Hyprland, wlogout, and SDDM on a Tuxedo Stellaris 15 with Nvidia GeForce RTX 3080, driver version 550.54.14 and Cuda 12.4.
I have not been able to find anything enlightening in the logs, as the warnings there also also there when I set the display manager to GDM and logout behaves as expected.
I did not, although admittedly I did not exhaust all possible options. My solution for now is just to log in to a tty and start the compositor (hyprland) from there.
I also bashed my head against this one for a while. I would get the black screen with a blinking cursor about 50% of the time when killing hyprland, and a crash log in journalctl.
I’m using UWSM and the thing that solved it for me was to exit hyprland with uswm stop instead of exit. I haven’t had the issue since changing but can still trigger the hand with hyprctl dispatch exit pretty reliably.
If you’re not using UWSM there’s a discussion here about the issue. In the linked comment someone posted a script that just nukes hyprland if it doesn’t exit gracefully, and others seemed to have some success with it.