No DP output on R36.3 with 6.8 kernel on Dell U2414H

Issue Overview

Users are experiencing issues with DisplayPort (DP) output when using the Nvidia Jetson Orin Nano Dev board with the R36.3 version and Linux kernel 6.8. The symptoms include:

• Monitor Detection: The monitor is detected by Xorg, as confirmed by the xrandr -q command, which shows the monitor connected but not displaying output correctly.

• Boot Behavior: The monitor works fine during boot and displays boot logs when SIMPLE_FB is enabled. However, once the system has booted, it either outputs a skewed image or no image at all when the display is connected during boot.

• Resolution Issues: Users report that while 1440p resolution causes problems, 1080p works without issues when using kernel 5.15.

• Frequency of Issues: This issue appears consistently for users who upgraded to kernel 6.8, particularly those using specific monitors like the Dell U2414H.

• Impact on User Experience: The inability to get a proper display output significantly hampers usability, especially for development and testing purposes.

Possible Causes

Potential reasons for this issue include:

• Hardware Incompatibilities: Certain monitors may not be fully compatible with the newer kernel versions, leading to display issues.

• Software Bugs: There may be unresolved bugs in the kernel version 6.8, particularly related to the framebuffer driver that affects how displays are initialized.

• Configuration Errors: Incorrect settings in the device tree or framebuffer configuration could prevent proper initialization of the display.

• Driver Issues: Changes in how drivers interact with hardware in kernel versions could lead to failures in display output.

• Environmental Factors: Poor quality or incompatible DisplayPort cables can lead to signal issues, as noted by some users.

• User Errors: Incorrectly connecting or configuring displays during boot can lead to unexpected behavior.

Troubleshooting Steps, Solutions & Fixes

To resolve the issue, users can follow these steps:

1. Verify Monitor Connection:

   • Ensure that the monitor is properly connected to the Jetson board.
   • Test different DisplayPort cables to rule out cable issues.

2. Check Kernel Version:

   • Confirm that you are running kernel version 6.8 by executing:

     uname -r
     

3. Test Different Resolutions:

   • If experiencing issues at 1440p, try changing to 1080p resolution after booting:

     xrandr --output DP-0 --mode 1080p
     

4. Boot with Display Connected:

   • If possible, connect the display after the system has completed booting to see if it initializes correctly.

5. Review dmesg Logs:

   • Check for any suspicious output in dmesg logs that may indicate errors during initialization:

     dmesg | grep -i error
     

6. Modify Device Tree Configuration:

   • As a temporary fix, modify your device tree to assign a dummy driver name to the framebuffer node:

     /{
         chosen {
             framebuffer {
                 compatible = "nvidia-dummy";
                 status = "disabled";
             };
         };
     };
     

   • Note that this will disable Linux boot messages but may allow proper display initialization.

7. Revert Kernel Commit:

   • If you are comfortable compiling your own kernel, revert commit 5727dcfd8486399c40e39d2c08fe36fedab29d99 and rebuild:

     make clean
     make
     

8. Consult Documentation:

   • Refer to the "Bring Your Own Kernel" section in NVIDIA’s Jetson Linux Developer Guide for additional patches or updates that may address this issue.

9. Report Findings:

   • If problems persist after trying these solutions, consider reporting your findings on relevant forums or NVIDIA support channels for further assistance.

By following these troubleshooting steps and solutions, users should be able to diagnose and potentially fix the DP output issue on their Nvidia Jetson Orin Nano Dev board running kernel 6.8.