Can I turn HDMI output on after setting up by Jetcard?

I setup my Jetson nano using Jetcard. So it’s under headless setting.
Now I would like to turn HDMI output on in Jetson nano board. Is it possible?
I couldn’t find what setting’s set by Jetcard image for headless and what setting should I change for turn HDMI output on.
I’d appreciate any help.

Hi,

Sorry that we don’t know what is done my Jetcard image either. I think you could try

sudo systemctl set-default graphical.target

Thank you so much for the comment.
I tried " sudo systemctl set-default graphical.target ", and reboot. But still HDMI output isn’t turned on.

I also confirmed below, so “set-default graphical.target” setting is already valid.

jetson@jetson:~$ sudo systemctl get-default
graphical.target

I’d appreciate any other recommendations.

Hi,

Actually, this problem could to be either an easy one or even a hard one. But this depends on what “Jetcard image” has done.
If this image even disabled the HDMI from kernel, then it is possible for you to run any configuration on userspace to make it work.

  1. Please check if gdm3 is running on your system.

ps aux |grep gdm

  1. Please check the dmesg and share it with us so that I can tell you if the hdmi driver in kernel is still working.

Hi,
The result of checking gdm is below,

jetson@jetson:~$ ps aux | grep gdm
root 4628 0.0 0.1 236644 7792 ? Ssl Jul12 0:00 /usr/sbin/gdm3
root 4980 0.0 0.1 164624 7968 ? Sl Jul12 0:00 gdm-session-worker [pam/gdm-autologi
jetson 5362 0.0 0.1 160632 5696 tty1 Ssl+ Jul12 0:00 /usr/lib/gdm3/gdm-x-session --run-sc
jetson 14153 0.0 0.0 6700 668 pts/0 S+ 00:40 0:00 grep --color=auto gdm

Also I attach the result of dmesg .
dmesg.txt (56.8 KB)

I got my jetcard image from this link,

Thanks again.

I checked my status along above suggestion, but I don’t know how do I search next.
Can anyone help me?

Hi,

Your HDMI driver is still working but the ubuntu desktop is not showing up.

Please try to restart gdm3 service and see if the monitor has any response.

Thanks,
I tried as you mentioned, but still no signal is in the monitor.

jetson@jetson:~ sudo systemctl stop gdm3 jetson@jetson:~ sudo systemctl status gdm3
● gdm.service - GNOME Display Manager
Loaded: loaded (/lib/systemd/system/gdm.service; static; vendor preset: enabled)
Active: inactive (dead) since Thu 2020-07-23 00:41:24 PDT; 3s ago
Process: 4975 ExecStart=/usr/sbin/gdm3 (code=exited, status=0/SUCCESS)
Process: 4836 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
Main PID: 4975 (code=exited, status=0/SUCCESS)
Jul 18 20:05:40 jetson systemd[1]: Starting GNOME Display Manager…
Jul 18 20:05:41 jetson systemd[1]: Started GNOME Display Manager.
Jul 18 20:05:41 jetson gdm-autologin][5320]: gkr-pam: no password is available for user
Jul 18 20:05:42 jetson gdm-autologin][5320]: pam_unix(gdm-autologin:session): session opened for user jetson by (uid=0)
Jul 23 00:41:24 jetson systemd[1]: Stopping GNOME Display Manager…
Jul 23 00:41:24 jetson gdm3[4975]: GLib: g_hash_table_find: assertion ‘version == hash_table->version’ failed
Jul 23 00:41:24 jetson systemd[1]: Stopped GNOME Display Manager.

jetson@jetson:~ sudo systemctl start gdm3 jetson@jetson:~ sudo systemctl status gdm3
● gdm.service - GNOME Display Manager
Loaded: loaded (/lib/systemd/system/gdm.service; static; vendor preset: enabled)
Active: active (running) since Thu 2020-07-23 00:41:40 PDT; 7s ago
Process: 2713 ExecStartPre=/usr/share/gdm/generate-config (code=exited, status=0/SUCCESS)
Main PID: 2742 (gdm3)
Tasks: 4 (limit: 4190)
CGroup: /system.slice/gdm.service
└─2742 /usr/sbin/gdm3
Jul 23 00:41:46 jetson gdm-launch-environment][3025]: pam_unix(gdm-launch-environment:session): session closed for user gd
Jul 23 00:41:46 jetson gdm3[2742]: Child process -3043 was already dead.
Jul 23 00:41:46 jetson gdm3[2742]: Child process 3025 was already dead.
Jul 23 00:41:46 jetson gdm3[2742]: Unable to kill session worker process
Jul 23 00:41:46 jetson gdm-launch-environment][3046]: pam_unix(gdm-launch-environment:session): session opened for user gd
Jul 23 00:41:47 jetson gdm-launch-environment][3046]: pam_unix(gdm-launch-environment:session): session closed for user gd
Jul 23 00:41:47 jetson gdm3[2742]: Child process -3064 was already dead.
Jul 23 00:41:47 jetson gdm3[2742]: Child process 3046 was already dead.
Jul 23 00:41:47 jetson gdm3[2742]: Unable to kill session worker process
Jul 23 00:41:47 jetson gdm-launch-environment][3067]: pam_unix(gdm-launch-environment:session): session opened for user gd

I’m not sure, since I’m a very beginner at Linux system, but,
the scripts “create_display_service.py” is included in the Jetcard script. Isn’t it possible that this is rewriting the output settings of the display?

create_display_service.py

import argparse
import getpass
import os

STATS_SERVICE_TEMPLATE = “”"
[Unit]
Description=JetCard display service

[Service]
Type=simple
User=%s
ExecStart=/bin/sh -c “python3 -m jetcard.display_server”
WorkingDirectory=%s
Restart=always

[Install]
WantedBy=multi-user.target
“”"

STATS_SERVICE_NAME = ‘jetcard_display’

def get_stats_service():
return STATS_SERVICE_TEMPLATE % (getpass.getuser(), os.environ[‘HOME’])

if __name__ == ‘__main__’:
parser = argparse.ArgumentParser()
parser.add_argument(’–output’, default=‘jetcard_display.service’)
args = parser.parse_args()

with open(args.output, ‘w’) as f:
f.write(get_stats_service())

Hi,

Sorry that I cannot share much related to jetcard because I am not the owner of it. According to the content, it seems this python script(create_display_service.py) tries to add one systemd service. When this service starts, it will run command “python3 -m jetcard.display_server”. That is what I can tell you so far. I don’t know what application is jetcard.display_server. Maybe you could share this for us.

For my previous debug on gdm, please do below observation for me

  1. run command dmesg and check its timestamp

  2. restart gdm3 service (if you don’t know the command, please tell me)

  3. Check the dmesg and see if any new log is printed.

Thanks,

When I try above 3 steps, below new logs are printed.

[ 1100.829872] tegradc tegradc.0: blank - powerdown
[ 1101.333521] tegradc tegradc.0: blank - powerdown
[ 1101.862349] tegradc tegradc.0: blank - powerdown
[ 1102.393050] tegradc tegradc.0: blank - powerdown
[ 1102.954283] tegradc tegradc.0: blank - powerdown
[ 1103.437864] tegradc tegradc.0: blank - powerdown
[ 1104.040452] tegradc tegradc.0: blank - powerdown
[ 1104.579896] tegradc tegradc.0: blank - powerdown
[ 1105.232866] tegradc tegradc.0: blank - powerdown