From GDM - GNOME Display Manager: "The GNOME Display Manager (GDM) is a program that manages graphical display servers and handles graphical user logins."
Display managers provide X Window System and Wayland users with a graphical login prompt.
## 1.GDM auto-suspend (GNOME 3.28)
GDM uses a separate dconf database to control power management. To apply your user's power settings, copy them to GDM's dconf database:
```bash
IFS=$'\n'; for x in $(sudo -u username gsettings list-recursively org.gnome.settings-daemon.plugins.power); do eval "sudo -u gdm dbus-launch gsettings set $x"; done; unset IFS