I got a fresh install of a Jetson TK1 with Ubuntu 14.04. Then I upgraded it to Ubuntu 16.04, Ubuntu 18.04 and Ubuntu 20.04.
For 18 and 20 the display manager started to fail, not starting the Desktop.
When I use systemctl status lightdm.service the output is:
● lightdm.service - Light Display Manager
Loaded: loaded (/lib/systemd/system/lightdm.service; indirect; vendor preset: enabled)
Drop-In: /lib/systemd/system/display-manager.service.d
└─xdiagnose.conf
Active: failed (Result: exit-code) since Wed 2021-03-17 21:36:18 UTC; 2 months 2 days ago
Docs: man:lightdm(1)
Main PID: 768 (code=exited, status=1/FAILURE)
Mar 17 21:36:18 tegra-ubuntu systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 4.
Mar 17 21:36:18 tegra-ubuntu systemd[1]: Stopped Light Display Manager.
Mar 17 21:36:18 tegra-ubuntu systemd[1]: lightdm.service: Start request repeated too quickly.
Mar 17 21:36:18 tegra-ubuntu systemd[1]: lightdm.service: Failed with result 'exit-code'.
Mar 17 21:36:18 tegra-ubuntu systemd[1]: Failed to start Light Display Manager.
Mar 17 21:36:18 tegra-ubuntu systemd[1]: lightdm.service: Triggering OnFailure= dependencies.
Mar 17 21:36:19 tegra-ubuntu systemd[1]: lightdm.service: Start request repeated too quickly.
Mar 17 21:36:19 tegra-ubuntu systemd[1]: lightdm.service: Failed with result 'exit-code'.
Mar 17 21:36:19 tegra-ubuntu systemd[1]: Failed to start Light Display Manager.
Then if I type lightdm --test-mode --debug the output is:
[+0.00s] DEBUG: Logging to /home/ubuntu/.cache/lightdm/log/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.30.0, UID=1000 PID=25721
[+0.00s] DEBUG: Loading configuration dirs from /var/lib/snapd/desktop/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-guest.conf
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-log-backup.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity.conf
[+0.01s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.01s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.01s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.01s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.01s] DEBUG: Running in user mode
[+0.01s] DEBUG: Registered seat module local
[+0.01s] DEBUG: Registered seat module xremote
[+0.01s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.01s] DEBUG: Failed to get thread scheduler attributes: Function not implemented
[+0.05s] DEBUG: _g_io_module_get_default: Found default implementation gvfs (GDaemonVfs) for ?gio-vfs?
[+0.06s] DEBUG: Monitoring logind for seats
[+0.06s] DEBUG: New seat added from logind: seat0
[+0.06s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.06s] DEBUG: Seat seat0: Starting
[+0.07s] DEBUG: Seat seat0: Creating greeter session
[+0.07s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.07s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+0.08s] DEBUG: Seat seat0: Creating display server of type x
[+0.08s] DEBUG: posix_spawn avoided (fd close requested)
[+0.09s] DEBUG: Seat seat0: Starting local X display
[+0.09s] DEBUG: XServer 0: Logging to /home/ubuntu/.cache/lightdm/log/x-0.log
[+0.09s] DEBUG: XServer 0: Writing X server authority to /home/ubuntu/.cache/lightdm/run/root/:0
[+0.10s] DEBUG: XServer 0: Launching X Server
[+0.10s] DEBUG: Launching process 25727: /usr/bin/X -core :0 -seat seat0 -auth /home/ubuntu/.cache/lightdm/run/root/:0 -nolisten tcp
[+0.10s] DEBUG: XServer 0: Waiting for ready signal from X server :0
[+0.10s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.10s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.18s] DEBUG: Process 25727 terminated with signal 6
[+0.18s] DEBUG: XServer 0: X server stopped
[+0.18s] DEBUG: XServer 0: Removing X server authority /home/ubuntu/.cache/lightdm/run/root/:0
[+0.18s] DEBUG: Seat seat0: Display server stopped
[+0.18s] DEBUG: Seat seat0: Stopping session
[+0.18s] DEBUG: Seat seat0: Session stopped
[+0.18s] DEBUG: Seat seat0: Stopping display server, no sessions require it
[+0.18s] DEBUG: Seat seat0: Stopping; greeter display server failed to start
[+0.18s] DEBUG: Seat seat0: Stopping
[+0.18s] DEBUG: Seat seat0: Stopped
[+0.18s] DEBUG: Required seat has stopped
[+0.18s] DEBUG: Stopping display manager
[+0.18s] DEBUG: Display manager stopped
[+0.18s] DEBUG: Stopping daemon
[+0.18s] DEBUG: Exiting with return value 1
I have tried some solutions or commands, but anyone helped me.
Thanks in advance.
Best regards. Alessandro
