How to Set HDMI Display as Default on Jetson Orin Nano Developer Kit

Issue Overview

Users of the Jetson Orin Nano Developer Kit are experiencing difficulties in setting the HDMI display as the default output for custom carrier boards. The issue occurs during the configuration process, specifically when modifying the device tree source (DTS) files. Despite attempts to include HDMI-specific device tree source include (DTSI) files and updating the kernel image and device tree blob (DTB), the HDMI settings are not taking effect as expected.

Possible Causes

1. Incorrect modification of device tree files:
   The user may have made errors while editing the ‘tegra234-p3767-0000-p3768-0000-a0.dts’ file or incorrectly included the ‘tegra234-dcb-p3767-0000-hdmi.dtsi’ file.

2. Incompatible custom carrier board:
   The custom carrier board may have hardware differences that are not accounted for in the standard device tree files.

3. Outdated or incompatible JetPack version:
   The user is using JetPack version 35.3.1, which may not fully support the desired HDMI configuration for custom boards.

4. Incorrect kernel or DTB update process:
   The process of updating the kernel Image and DTB may not have been performed correctly, resulting in the changes not being applied.

5. Missing additional configuration steps:
   There might be additional steps required to enable HDMI output that are not covered by simply modifying the device tree files.

Troubleshooting Steps, Solutions & Fixes

1. Use default configuration:
   As suggested by an NVIDIA representative, try using the p3509-a02 + p3767 board configuration, which has HDMI enabled by default. This can help determine if the issue is specific to your custom configuration or a more general problem.

   # Example command to flash with default configuration (adjust as needed)
   sudo ./flash.sh jetson-orin-nano-devkit mmcblk0p1
   

2. Verify device tree modifications:
   Double-check your modifications to the ‘tegra234-p3767-0000-p3768-0000-a0.dts’ file. Ensure that the ‘tegra234-dcb-p3767-0000-hdmi.dtsi’ is correctly included and that there are no syntax errors.

   # Example of correct inclusion in DTS file
   /dts-v1/;
   #include "tegra234-p3767-0000-p3768-0000-a0.dtsi"
   #include "tegra234-dcb-p3767-0000-hdmi.dtsi"
   

3. Rebuild and reflash:
   After verifying your device tree modifications, rebuild the device tree blob and kernel, then reflash your Jetson Orin Nano.

   # Rebuild DTB
   dtc -I dts -O dtb -o tegra234-p3767-0000-p3768-0000-a0.dtb tegra234-p3767-0000-p3768-0000-a0.dts
   
   # Reflash the Jetson (adjust paths as needed)
   sudo ./flash.sh -r board=jetson-orin-nano-devkit mmcblk0p1
   

4. Check HDMI detection:
   After booting with the updated configuration, check if the system detects the HDMI display:

   xrandr --query
   

   Look for an HDMI output in the list of available displays.

5. Update JetPack:
   Consider updating to the latest JetPack version compatible with your Jetson Orin Nano. This may resolve compatibility issues and provide better support for custom configurations.

   Visit the NVIDIA Jetson Download Center (https://developer.nvidia.com/embedded/jetpack) for the latest version.

6. Consult official documentation:
   Review the Jetson Linux Developer Guide for detailed information on customizing device trees and configuring displays:
   https://docs.nvidia.com/jetson/archives/r35.3.1/DeveloperGuide/

7. Seek community support:
   If the issue persists, consider posting a more detailed description of your custom carrier board and configuration in the NVIDIA Developer Forums, specifically in the Jetson Orin Nano category:
   https://forums.developer.nvidia.com/c/agx-autonomous-machines/jetson-embedded-systems/jetson-orin-nano/659

Remember to provide detailed information about your custom carrier board, exact modifications made to the device tree, and any error messages or logs when seeking further assistance.