Failed to open display=:0 on tx2

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hi All,

I replaced username and hostname to something else. now I am getting “failed to open display=:0” when I run a GUI application. I tried adding adding cookies to the already created Xauthority file for the previous user. but it didn’t work. can anybody suggest any other ways to fix it?

Regards,
Shivlal

2

Are you starting a remote application on a Jetson while logged in to a PC? Or are you starting from a different user on the same Jetson? Many details of how you are logging in and connecting are required.

FYI, the “DISPLAY”, in the syntax “DISPLAY=:0”, only works on the local computer. Once a remote computer is referenced things change. However, which end is remote versus local might get a bit confusing. Failing to use “DISPLAY=:0” can be either because the display was not opened on the system this refers to, or it can be because of security. Hard to tell without complete details.

3

You may try to add your new user to video group:

sudo usermod the_new_user_name -a -G video
4

Hi linuxdev,

The application is built locally on tx2 and it uses x server. I am setting DISPLAY=:0.

I replaced username nvidia and home folder with a new user and I am running this application from the new user.

Thanks,

5

When you are actually logged in to the GUI from the user who runs the program, what do you see from:

echo $DISPLAY

Is this “:0”? If it is something else, e.g., “:1”, then you would need to use that instead for running the program. For example, if the program were “xterm”, with “:1”, then at your login to the same user name, the program launch would be either of:

DISPLAY=:1 xterm
# OR:
export DISPLAY=:1
xterm

Note that if you use ssh for remote login, then you should be sure to not use the “-X” or “-Y” options for forwarding.

1 Like
6

Hi linuxdev,

I am logging through ssh without X forwarding and I am exporting DISPLAY=:0. if I do “echo $DISPLAY” it returns :0.

Thanks,

7

Is it correct that this is what the echo says from the running local GUI? If you export “:0”, then it will always echo that, but my goal is to know for certain that the logged in GUI also says “:0”.

So just as a sanity check list, here are some things to look at:

  • The person logging in to the GUI must be the same person the ssh logs in as.
  • The ssh export of DISPLAY should be the same as the echo of "$DISPLAY" at the GUI.
  • @Honey_Patouceul mentioned group membership. If the person logged in to the GUI is not a member of the "video" group, then the application will still not be able to run in a number of circumstances. As a test, if your user name happens to be "nvidia", then you could see if your user is a member of video via this: 
    # Your user name, "nvidia" for example, should appear in the reported "video" line:
grep video /etc/group

    If this fails, then the reply from @Honey_Patouceul would remedy this.

  • Verify that the same user in the same GUI can run the application directly.

Please note that if you changed a user account name, and did not use the correct tools, then probably the secondary groups would not have correctly changed. As a result the new name would no longer be a member of the same secondary groups.