JLinkGDBServer connects to JLinkRemoteServer but not to the J-Link

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    • JLinkGDBServer connects to JLinkRemoteServer but not to the J-Link

      I am attempting to fix a problem with a system that, up until today, was working fine (not perfectly, but fine).

      My system is configured as such:
      I am developing for an ARM target using Linux build tools running under WSL. WSL has no ability to use or see USB devices. However, the Segger tools run fine under WSL.

      I have my J-Link Ultra+ connected via USB to my machine. I launch J-Link Remote Server with the "Use LAN" option selected. The Remote Server indicates that it detects my J-Link.
      Next, I attempt to launch a debug session. I have configured my launch to invoke JLinkGDBServer in WSL with the "-select ip=localhost" option (among the other, more standard options). When the GDB server is launched, I see that the Remote Server recognizes a connection. However, GDB is unable to connect to the J-Link itself. The exact output from the J-Link GDB Server is:


      Source Code

      1. SEGGER J-Link GDB Server V6.56a Command Line Version
      2. JLinkARM.dll V6.56a (DLL compiled Nov 25 2019 16:58:26)
      3. Command line: -if swd -port 50000 -swoport 50001 -telnetport 50002 -device STM32F756IG -select ip=localhost
      4. -----GDB Server start settings-----
      5. GDBInit file: none
      6. GDB Server Listening port: 50000
      7. SWO raw output listening port: 50001
      8. Terminal I/O port: 50002
      9. Accept remote connection: yes
      10. Generate logfile: off
      11. Verify download: off
      12. Init regs on start: off
      13. Silent mode: off
      14. Single run mode: off
      15. Target connection timeout: 0 ms
      16. ------J-Link related settings------
      17. J-Link Host interface: IP
      18. J-Link script: none
      19. J-Link settings file: none
      20. ------Target related settings------
      21. Target device: STM32F756IG
      22. Target interface: SWD
      23. Target interface speed: 4000kHz
      24. Target endian: little
      25. Connecting to J-Link...
      26. Connecting to J-Link failed. Connected correctly?
      27. GDBServer will be closed...
      28. Shutting down...
      29. Could not connect to J-Link.
      Display All
      Note, that while this snippet shows V6.56a, I have tried this with the most up-to-date segger tools on both ends, and it doesn't fix the problem. This capture was from an attempt at downgrading to a version that used to work.

      One last thing to note: it seems that when the GDB session fails, the connection does not detach properly from JLinkRemoteServer. This happens with all versions of the tools that I tried.

      Can anyone provide suggestions on how to debug this problem?
    • After doing some further testing, I have determined that it is possible to connect to both the J-Link and the target using 'JLinkExe ip localhost' from inside WSL. This verifies that I am not, in fact, a crazy person and everything is physically configured as it should be. I am beginning to think there is a problem with JLinkGDBServer itself, and it for whatever reason cannot connect to the J-Link reliably through the ip connection.
    • New

      Hi,
      Thank you for your inquiry.
      We are not aware of any issues related to the J-Link GDB Server in combination with the J-Link Remote Server.

      When using the J-Link GDB Server in combination with the J-Link Remote Server, the GDB server is supposed to connect to the remote server.
      The connection should be established like this:
      Client side (GDB client <-> GDB server) <-> Host side (Remote server <-> J-Link).

      Could you please make sure that
      1) the J-Link Remote Server is connected to the J-Link correctly
      2) the J-Link GDB Server is connected to the J-Link Remote Server correctly.
      3) the GDB Client is connected to the J-Link GDB Server correctly

      After checking your setup and points 1-3:
      Could you please send us a screenshot of each of these applications' and their outputs?
      Could you please send us a J-Link log file? How to enable:
      wiki.segger.com/J-Link_DLL#Enable_J-Link_Log_File

      Best regards,
      Fabian
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