Nvidia jetson xaiver nx display command not giving output

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

Hi
When we run display related command on nvidia(xrandr,echo $DISPLAY etc)
it says “Can’t open display”, (Display is attached to nvidia through DP port).

3

Where do you type this command? The tty console on monitor or the terminal from remote access?

Have you tried DISPLAY=:1?

4

Hi @WayneWWW
I used to type this command on tty console .Its says “Can’t open display”
Actually I need to know how many displays are connected,so is there any other method (commands) which give no of displays

5

Hi,

Are you able to see the ubuntu desktop on your monitor? If you disable desktop, then X will not initiate so xrandr will not work.

6

xrandr,echo $DISPLAY all display related commands are working fine in GUI

7

Hi,

I also cannot understand one point here.

Why do you mention “echo $DISPLAY” gives you error? This command just tries to print the variable. The system does not know it has anything to do with the display. It is just a string.

8

I need to know how many displays are connected through Nvidia using tty console ,so can you please suggest me the way ?

9

You can also check how many fb nodes are there under /dev/.

or you can type

sudo -s
cd /sys/kernel/debug/

and check how many tegradc.x are there.

Also, we cannot reproduce your problem because our console can see xrandr result even when we use remote access. That is what I concern.

10

Hi @WayneWWW
Can you Please suggest any other way(apart from xrandr) through which we can do Display mirroring/extention/Off
Thanks

11

Hi,

Without X11, what you saw is called fbcon. That one has only limited functionality.

https://www.kernel.org/doc/Documentation/fb/fbcon.txt

Thus, I don’t think mirroring and extend could be achieved.

As for “off”, just blank the screen by

cd /sys/class/graphics/fbX
echo 1 > blank