How to use xrandr when ssh login

[bross_kuo]

Hi NV,
we want to use xrandr when login ssh,
1.sudo su
2.export DISPLAY=:0
3.xrandr
but it doesn’t work, and show follow message,

No protocol specified
Can’t open display :0

any suggestion?
thanks.

[WayneWWW]

Do you have physical monitor connected on your jetson?

[bross_kuo]

Hi Wayne,
yes, we have physical monitor connect to jetson with HDMI,
but we still need to use xrandr on login ssh,
in case if hit display issue make no display on monitor,
thanks.

[WayneWWW]

please try with DISPLAY=:1. Sometimes the :0 is occupied by other process.

[bross_kuo]

Hi Wayne,
got fail result as follow message,
thanks.

root@tegra-ubuntu:/home/asus# export DISPLAY=:1
root@tegra-ubuntu:/home/asus# xrandr
Can’t open display :1

[WayneWWW]

Please do not run as root and it will work.

[bross_kuo]

Hi Wayne,
got the same result,
thanks.

asus@tegra-ubuntu:~$ export DISPLAY=:1
asus@tegra-ubuntu:~$ xrandr
Can’t open display :1

[WayneWWW]

Use :0

[bross_kuo]

Hi Wayne,
it’s work,
thanks.

[linuxdev]

Incidentally, the original error was probably that you used sudo. The DISPLAY must be accessed by the same user to which the DISPLAY is running. My guess is that your X was running under a name other than root.

[bross_kuo]

Hi linuxdev,
got it,
thanks for your information