Detect GPIO pins on boot and make decision accordingly

[WayneWWW]

I am not sure what happened on your side. But this is the method that was validated by us and other customers also.

Try to run Weston JetPack 4.3 - L4T R32.3.1, system halted

Hi Rock2000, Please reference below steps to start weston: 1. Stop the display manager: $ sudo systemctl stop gdm $ sudo loginctl terminate-seat seat0 2. For Weston 6.0 use tegra_drm driver $ sudo modprobe tegra-udrm modeset=1 3. Unset the DISPLAY environment variable: $ unset DISPLAY 4. Create a temporary xdg directory: $ mkdir /tmp/xdg $ chmod 700 /tmp/xdg 5. Start the Weston compositor: $ sudo XDG_RUNTIME_DIR=/tmp/xdg weston --idle-time=0 &

Only step 1 for your case. The rest is for enabling Weston. Not related ot your issue.

[Abo_Jaafar]

@WayneWWW
That’s weird…
I was able to stop and start the display using “sudo init 3” and “sudo init 5” , and I think it’s enough in my case for now.
Back to my other question, Is there no way I can get the python application to display its output on the screen after startup without Xserver?

Thank you some much for your assistance.

[WayneWWW]

This depends on what kind of framework your python app is using to render something to the screen.

If the reason you disable gdm3 and still want to render something is just because of the Ubuntu desktop, then you can still run startX or xinit int the background. Which will enable Xserver but no GUI.

[Abo_Jaafar]

@WayneWWW
Ok, so lets say I am starting my system normally with a gui and the password is disabled (but the login screen still needs me to press “enter”).
How can my python application display its output using Opencv (cv2.imshow) on the screen after startup ?
Is there any way to bypass the login screen?
The application can be delayed a little if that helps…

[WayneWWW]

I am still not sure why “login screen” is the concern here. Is your systemd service got stuck by the “login screen” here?

Also, what kind of “login screen” we are talking about here? Is that on your HDMI screen under console mode or GUI mode?

[Abo_Jaafar]

@WayneWWW ,
My concern with the login screen is that “I think” it’s not allowing me display my output using Opencv, After I login the app runs fine, and displays as expected,however I need the application to display its output on the screen automatically after startup.
I am talking about the Gui login screen.
I tried the solution of this thread, but I am still stuck on the login screen:

Jetson Nano auto log in account when poweron without need to press enter

Hi Hqm996, Actually, you only need set ‘User Settings’ and change the password to ‘Not asked on login’. [image] If you still stuck on login screen, please add below lines: $ sudo vim /etc/lightdm/lightdm.conf.d/50-nvidia.conf Add below two lines: autologin-user=nvidia autologin-user-timeout=0

[Abo_Jaafar]

@WayneWWW
Nvm, I was able to enable auto-login by adding the following two lines to “/etc/lightdm/lightdm.conf” :
autologin-user=jetson
autologin-user-timeout=0

So my system is entering the desktop screen, but the app is failing to output the images on the screen, knowing that another application (which doesn’t need to display) works just fine.
If I run the application manually it also works fine, but it’s failing to run automatically on startup.
“sudo systemctl status mysthing.service”
gives: "python3[6574]: cannot open display " as an error

[Abo_Jaafar]

@WayneWWW
I also tried adding a 15 second delay before starting the python application, which did not work.

[Abo_Jaafar]

@WayneWWW
@kayccc
@JerryChang
Any idea why the app is failing to open the camera after power up ?

[Abo_Jaafar]

I found the solution here:

Startup/boot script with systemd issues

I found a solution. Thanks for your help @AastaLLL. It looks like it was my service script that was the issue. I added XAUTHORITY and DISPLAY and it works great now. ExecStartPre was also added just to delay the start of the script but wasn’t the reason for it working. Working code looks like this: [Unit] Description=Execute this on boot After=multi-user.target [Service] Environment=XAUTHORITY=/home/ag72/.Xauthority Environment=DISPLAY=:0 ExecStartPre=/bin/sleep 10 ExecStart=/usr/bin/python…

Thank you for your assistance.