JLinkGDBServerExe: cannot connect to X server

I’m trying to debug a project using VS Code + WSL2 Ubuntu 20.04 LTS

The only thing I can think of is that maybe I should try uninstalling+reinstalling JLink. I remember having issues installing it and maybe I somehow broke something?

When I google search the issue, I end up here, which says it might be some sort of permissions issue: https://askubuntu.com/questions/175611/cannot-connect-to-x-server-when-running-app-with-sudo

I’m not sure what to make of the idea that it’s a permissions issue.

When I try to debug, I get this error message in the DEBUG CONSOLE:

Please check OUTPUT tab (Adapter Output) for output from /usr/bin/JLinkGDBServerExe
Launching server: "/usr/bin/JLinkGDBServerExe" "-if" "swd" "-port" "50000" "-swoport" "50001" "-telnetport" "50002" "-device" "nRF52840_xxAA"

I get this error message in the Adapter Output:

JLinkGDBServerExe: cannot connect to X server 

Here are my settings:

settings.json

{
    "cortex-debug.JLinkGDBServerPath": "/usr/bin/JLinkGDBServerExe", // Linux
    "cortex-debug.armToolchainPath": "/home/4a42/gcc-arm-none-eabi-9-2020-q2-update/bin/", // Linux
    "C_Cpp.default.cppStandard": "c++17",
    "C_Cpp.default.cStandard": "c11",
    "C_Cpp.default.intelliSenseMode": "clang-arm",
    "C_Cpp.updateChannel": "Insiders",
    "cmake.cmakePath": "/usr/local/bin/cmake", // Linux
    "cmake.configureOnOpen": false,
    "cmake.generator": "Ninja Multi-Config",
    "cmake.configureArgs": [
        "-DENABLE_CLANG_TIDY:BOOL=TRUE"
    ],
    "clang-tidy.lintOnSave": false,
    "clang-tidy.buildPath": "${workspaceFolder}/build"
}

launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Debug",
            "type": "cortex-debug",
            "request": "launch",
            "servertype": "jlink",
            "executable": "${command:cmake.launchTargetPath}",
            "cwd": "${workspaceRoot}",
            "device": "nRF52840_xxAA",
            "svdFile": "${workspaceRoot}/lib/nRF5-SDK/modules/nrfx/mdk/nrf52840.svd"
        }
    ]
}

Version: 1.51.1 (system setup)
Commit: e5a624b788d92b8d34d1392e4c4d9789406efe8f
Date: 2020-11-10T23:34:32.027Z
Electron: 9.3.3
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Windows_NT x64 10.0.19041

marus25.cortex-debug v0.3.7

[haneefdm]

In the next release, there will be no more graphical display with JLink. If you want to enable it, you have to use -gui in serverArgs. It is unnatural for a command-line tool to be running a GUI as this makes many things complicated.

[hwmaier]

You can disable the progress bar and probably prevent this issue if you don’t run a GUI by passing `serverArgs": [“-nogui”] in your launch.json. That prevents the JLink DLL to show a GUI progress window.