i played around with SDDM on a Manjaro Gnome system to get rid of the boring gnome login screen. After setup SDDM with via Install Display Managers - Manjaro
i’m not able to lock the screen anymore because i get the error that lockscreen needs GDM.
is there a way to tell the system to use SDDM for lockscreen?
In Gnome Shell 3.6 and earlier, the old gnome-screensaver program was present, and if GDM was not running, gnome-screensaver would be invoked - allowing you to lock the screen.
Starting in Gnome Shell 3.8 (included in Fedora 19), gnome-screensaver support has been dropped completely. This was done for three reasons: reduced code complexity coupled with the fact that the screensaver is seen as an unneeded feature, and the fact that the eventual move to Wayland will require screensaver, locking, etc. support to be in the compositor.
So the only Gnome-integrated way of locking the screen is to have GDM running, which will respond to a dbus message telling it to lock the screen. Other display managers (such as XDM) have not been designed to respond to this dbus message, and so the screen cannot be locked.
In old versions of gnome the command gnome-screensaver-command -l would lock your screen. As gnome-screensaver is no more in gnome 3.8 you now have to send a dbus call. I think this is then handled by GDM.
SDDM is not a lock screen; it’s a display manager, which incorporates the Plasma login screen, and that’s quite a different thing from a screen locker.
The screen locking component in KDE Plasma is not SDDM but kscreenlocker, and as you could read, this won’t work with GNOME, even if only because GNOME relies on GDM for its lock screen.
Furthermore, it’s never a good idea to try replacing essential GNOME components by KDE components. Plasma is more forgiving than GNOME in that regard.
thanks for the explanation! I did not know that Gnome a is so inflexible. My goal was actually just to have a nicer login screen, since you can hardly customize Gnome’s login screen if at all anymore.
Disclaimer: not used for years now so don t know if It still work at this days.
For a screen saver on gnome instead use gdm you can use budgie-screensaver. Is a fork of the old gnome-screensaver but maintained for budgie.