- GDM is the GNOME Display Manager, it is the little program that runs in the background, runs your X sessions, presents you with a login box and then tells you to bug off because you forgot your password. It does pretty much everything that you would want to use xdm for, but does not involve as much crack. It does not use any code from xdm. It supports XDMCP, and in fact extends XDMCP a little bit in places where I thought xdm was lacking (but is still compatible with xdm's XDMCP).
- 1 Installation
- 2 Configuration
- 3 Troubleshooting
GDM as the default greeter
To make GDM the default graphical login method for the system, use the packaged systemd service file,
gdm.service. Simply run the following command once to bring up GDM on boot:
# systemctl enable gdm.service
The arguments passed to the X server by
~/.xinitrc (such as those of
xsetroot) can also be added through xprofile:
#!/bin/sh # # ~/.xprofile # # Executed by gdm at login # xmodmap -e "pointer=1 2 3 6 7 4 5" # set mouse buttons up correctly xsetroot -solid black # sets the background to black
You can no longer use the gdmsetup command to configure GDM as of version 2.28. The command has been removed and GDM has been standardized and integrated with the rest of GNOME.
You can installAUR from the AUR to configure GDM, or use the following instructions.
Configure X server access permission:
# xhost +SI:localuser:gdm
Change the theme:
$ sudo -u gdm dbus-launch gnome-control-center
For more configuration options, do:
$ sudo -u gdm dbus-launch gconf-editor
and modify the following hierarchies:
/apps/gdm/simple-greeter /desktop/gnome/interface /desktop/gnome/background
If these commands fail with an error (e.g.
"Cannot open display") you can bring the two windows up when GDM starts by adding them to GDM's autostart. To do this first create the entry:
# cp -t /usr/share/gdm/autostart/LoginWindow/ /usr/share/applications/gnome-appearance-properties.desktop /usr/share/applications/gconf-editor.desktop
Then go back to GDM, do your changes and log back in. When you're done and want the window to stop opening with GDM run this:
# rm /usr/share/gdm/autostart/LoginWindow/gnome-appearance-properties.desktop /usr/share/gdm/autostart/LoginWindow/gconf-editor.desktop
For more information and advanced settings read this.
To enable automatic login with GDM, add the following to
/etc/gdm/custom.conf (replace username with your own):
# Enable automatic login for user [daemon] AutomaticLogin=username AutomaticLoginEnable=True
or for an automatic login with a delay:
[daemon] # for login with delay TimedLoginEnable=true TimedLogin=username TimedLoginDelay=1
If you want to bypass the password prompt in GDM then simply add the following line to
auth sufficient pam_succeed_if.so user ingroup nopasswdlogin
Make sure this line goes right before the
Then, add the group
nopasswdlogin to your system. You can do it graphically in
System > Administration > Users and Groups. See Groups for group descriptions and group management commands.
Now, when you use
System Settings -> System -> Users Accounts (command:
gnome-control-center) and set your user for
"Password: not asked at login" (by checking the
"Don't ask for password on login" option), your user will be automatically added to the
nopasswdlogin group and you will only have to click on your username to login.
GDM is using polkit and logind to gain permissions for shutdown. You can allow it without entering a password first by setting:
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE policyconfig PUBLIC "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN" "http://www.freedesktop.org/standards/PolicyKit/1.0/policyconfig.dtd"> <policyconfig> <action id="org.freedesktop.login1.power-off-multiple-sessions"> <description>Shutdown the system when multiple users are logged in</description> <message>System policy prevents shutting down the system when other users are logged in</message> <defaults> <allow_inactive>yes</allow_inactive> <allow_active>yes</allow_active> </defaults> </action> </policyconfig>
You can find all available logind options (e.g. reboot-multiple-sessions) here.
Changing default GDM session
If you want to change the default GDM session, you need to create (or edit) the file
Here is an example to set the default session to Cinnamon:
If you want to fall back to the old GDM, which also has a tool for configuring its settings, compile and install AUR.AUR from the
GDM fails on logout
If GDM starts up properly on boot, but fails after repeated attempts on logout, try adding this line to the daemon section of
gconf-sanity-check-2 exited with status 256
If GDM pops up an error about
gconf-sanity-check-2, you may check permissions in
/etc/gconf/gconf.xml.system (the latter should be
If GDM is still printing the message, try to empty the gdm home. Run as root:
rm -rf /var/lib/gdm/.*
If that doesn't help, try to set
/tmp owner and permissions to:
# chown -R root:root /tmp # chmod 777 /tmp
GDM root login
It is not advised to login as root, but if necessary you can edit
/etc/pam.d/gdm-password and add the following line before the line
auth required pam_deny.so:
auth sufficient pam_succeed_if.so uid eq 0 quiet
The file should look something like this:
... auth sufficient pam_succeed_if.so uid eq 0 quiet auth sufficient pam_succeed_if.so uid >= 1000 quiet auth required pam_deny.so ...
You should be able to login as root after restarting GDM.
GDM always uses default US-keyboard
Problem: Keyboard layout always switches to us; layout is reset when a new keyboard is plugged in.
[Desktop] Language=de_DE.UTF-8 # change to your default lang Layout=de nodeadkeys # change to your keyboard layout
add the following line to
/etc/X11/xorg.conf.d/10-evdev.conf, replacing fr with the appropriate keymap
Section "InputClass" Identifier "evdev keyboard catchall" MatchIsKeyboard "on" MatchDevicePath "/dev/input/event*" Driver "evdev" Option "XkbLayout" "fr" EndSection
GDM will not load after attempting to set up automatic login
To solve this issue, edit
/etc/gdm/custom.conf from a TTY and comment "AutomaticLoginEnable" and the "AutomaticLogin" lines.
# GDM configuration storage [daemon] #AutomaticLoginEnable=True #AutomaticLogin=user [security] [xdmcp] [greeter] [chooser] [debug]
GDM does not start after upgrading to 3.8 if using Intel graphics
To solve this problem, you may have to set your acceleration method to SNA. For more information, please refer to: Intel_Graphics#Choose_acceleration_method