Failed to start light display monitor (boot up failure )

hi, i tried to flash linux 18.04 on a jetson xavier nx board. during boot up i get a bunch of errors

  1. ran systemctl status lightdm.servicewith following output
    ● lightdm.service - Light Display Manager
    Loaded: loaded (/lib/systemd/system/lightdm.service; indirect; vendor preset:
    Active: failed (Result: exit-code) since Wed 2022-02-16 10:46:43 CET; 1h 52mi
    Docs: man:lightdm(1)
    Process: 5313 ExecStart=/usr/sbin/lightdm (code=exited, status=1/FAILURE)
    Process: 5310 ExecStartPre=/bin/sh -c [ "$(basename $(cat /etc/X11/default-dis
    Main PID: 5313 (code=exited, status=1/FAILURE)

feb 16 10:46:43 DCS systemd[1]: lightdm.service: Main process exited, code=exite
feb 16 10:46:43 DCS systemd[1]: lightdm.service: Failed with result ‘exit-code’.
feb 16 10:46:43 DCS systemd[1]: lightdm.service: Service hold-off time over, sch
feb 16 10:46:43 DCS systemd[1]: lightdm.service: Scheduled restart job, restart
feb 16 10:46:43 DCS systemd[1]: Stopped Light Display Manager.
feb 16 10:46:43 DCS systemd[1]: lightdm.service: Start request repeated too quic
feb 16 10:46:43 DCS systemd[1]: lightdm.service: Failed with result ‘exit-code’.
feb 16 10:46:43 DCS systemd[1]: Failed to start Light Display Manager.

  1. ran lightdm --test-mode --debug with the following output:
    [+0.00s] DEBUG: Logging to /home/dcs_user/.cache/lightdm/log/lightdm.log
    [+0.00s] DEBUG: Starting Light Display Manager 1.26.0, UID=1000 PID=7767
    [+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
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity.conf
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
    [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/60-lightdm-gtk-greeter.conf
    [+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
    [+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
    [+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf.d/50-nvidia.conf
    [+0.00s] DEBUG: [SeatDefaults] is now called [Seat:], please update this configuration
    [+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
    [+0.00s] DEBUG: Running in user mode
    [+0.00s] DEBUG: Registered seat module local
    [+0.00s] DEBUG: Registered seat module xremote
    [+0.00s] DEBUG: Registered seat module unity
    [+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
    [+0.05s] DEBUG: Monitoring logind for seats
    [+0.05s] DEBUG: New seat added from logind: seat0
    [+0.05s] DEBUG: Seat seat0: Loading properties from config section Seat:

    [+0.05s] DEBUG: Seat seat0: Starting
    [+0.05s] DEBUG: Seat seat0: Creating greeter session
    [+0.06s] DEBUG: Loading users from org.freedesktop.Accounts
    [+0.06s] DEBUG: User /org/freedesktop/Accounts/User1000 added
    [+0.06s] DEBUG: Seat seat0: Creating display server of type x
    [+0.07s] DEBUG: Seat seat0: Starting local X display
    [+0.07s] DEBUG: XServer 0: Logging to /home/dcs_user/.cache/lightdm/log/x-0.log
    [+0.07s] DEBUG: XServer 0: Writing X server authority to /home/dcs_user/.cache/lightdm/run/root/:0
    [+0.07s] DEBUG: XServer 0: Launching X Server
    [+0.08s] DEBUG: Launching process 7780: /usr/bin/X -core :0 -seat seat0 -auth /home/dcs_user/.cache/lightdm/run/root/:0 -nolisten tcp
    [+0.08s] DEBUG: XServer 0: Waiting for ready signal from X server :0
    [+0.08s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
    [+0.08s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
    [+0.73s] DEBUG: Process 7780 terminated with signal 6
    [+0.73s] DEBUG: XServer 0: X server stopped
    [+0.73s] DEBUG: XServer 0: Removing X server authority /home/dcs_user/.cache/lightdm/run/root/:0
    [+0.73s] DEBUG: Seat seat0: Display server stopped
    [+0.73s] DEBUG: Seat seat0: Stopping session
    [+0.73s] DEBUG: Seat seat0: Session stopped
    [+0.73s] DEBUG: Seat seat0: Stopping display server, no sessions require it
    [+0.73s] DEBUG: Seat seat0: Stopping; greeter display server failed to start
    [+0.73s] DEBUG: Seat seat0: Stopping
    [+0.73s] DEBUG: Seat seat0: Stopped
    [+0.73s] DEBUG: Required seat has stopped
    [+0.73s] DEBUG: Stopping display manager
    [+0.73s] DEBUG: Display manager stopped
    [+0.73s] DEBUG: Stopping daemon
    [+0.74s] DEBUG: Exiting with return value 1

  2. the xorg.cnfg file contents:

Copyright (c) 2017, NVIDIA CORPORATION. All Rights Reserved.

This is the minimal configuration necessary to use the Tegra driver.

Please refer to the xorg.conf man page for more configuration

options provided by the X server, including display-related options

provided by RandR 1.2 and higher.

Disable extensions not useful on Tegra.

Section “ServerLayout”
Identifier “Default Layout”
Screen “Default Screen” 0 0
InputDevice “Keyboard0” “CoreKeyboard”
InputDevice “Mouse0” “CorePointer”
EndSection

Section “Module”
SubSection “extmod”
Option “omit xfree86-dga”
EndSubSection
Load “glx”
Disable “dri”
EndSection

  1. also the USB ports and ethernet ports arent working, i can only ssh into the board using b type usb output port meant for debugging.

  2. when i run : nvidia-detector
    output:
    none
    none

i am not sure why this is happning. is there a problem in flashing? like, drivers used for display and output devices such as keyboard and mouse havent been built properly?

Hello @deepakjoshi9806,

can you please provide some more details on your setup:

  1. is that being tested on a Nvidia Devkit?
  2. What L4T/Jetpack version are you testing?
  3. Is that a custom design?

hello, yes its a devkit. and I was trying to flash jetpack 4.6.2.

Turns out I was suppose to flash jetpack 4.6.1 instead of 4.6.2 .
Thanks for the follow up, the board is working perfectly fine now :)

Thanks for letting us know that it is now working as expected.

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