Custom v4l2-controls for Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties in creating and implementing custom v4l2-controls for the Nvidia Jetson Orin Nano Dev Board, specifically for adding test patterns and mirroring and flipping controls. The main challenge lies in installing only the modified tegra-camera module without reinstalling all user modules. This issue is particularly relevant for users working with Jetpack 6 (r36.3) and differs from previous versions (Xavier-nx and Nano) where changes were part of the image and could be updated by rebuilding and placing the image in the boot folder.

Possible Causes

1. Module Build Configuration: The tegra-camera module is currently built as a loadable module (obj-m) rather than being built into the kernel, making isolated updates challenging.

2. Jetpack Version Differences: The transition to Jetpack 6 has altered the way custom modifications are handled compared to previous versions, potentially causing confusion for users familiar with the old method.

3. Limited Documentation: Users may be unaware of the correct procedures for implementing custom controls in the new Jetpack environment.

4. Kernel Configuration: The current kernel configuration may not be optimized for building tegra-camera as a built-in module, which could facilitate easier updates.

Troubleshooting Steps, Solutions & Fixes

1. Consider Building tegra-camera as Built-in:

   • Examine your kernel’s defconfig file.
   • Look for the tegra-camera entry. If it’s set to ‘M’, it’s currently built as a module.
   • Change the setting to ‘Y’ to build it as part of the kernel, allowing for Image file updates.

2. Review Kernel Configuration:

   • Share your defconfig file with the community or support team for expert review and guidance on potential modifications.

3. Consult Developer Guide:

   • Refer to the "Bring Your Own Kernel 6" section in the developer guide for detailed instructions on kernel modifications and module building.

4. Investigate Alternative Build Methods:

   • Since tegra-camera is part of nvidia-oot and the default Makefile sets it as obj-m, explore options to modify the build process without relying solely on defconfig changes.

5. Custom Module Installation:

   • Research methods to install only the modified tegra-camera.ko module without affecting other user modules.
   • This may involve manual module insertion or creating a custom installation script.

6. Community Support:

   • Engage with the Nvidia developer community for specific guidance on implementing custom v4l2-controls in Jetpack 6.
   • Share your exact requirements and the modifications you’ve made to receive tailored advice.

7. Kernel Recompilation:

   • If building tegra-camera as a built-in module is not feasible, consider recompiling the entire kernel with your custom changes.
   • This approach, while more time-consuming, ensures all dependencies are correctly handled.

8. Documentation Update Request:

   • Contact Nvidia support or contribute to community documentation to improve guidelines for custom v4l2-control implementation in Jetpack 6.

It’s worth underlining that this issue may require further investigation, as the forum discussion did not provide a definitive solution. Users are encouraged to experiment with the suggested approaches and report back their findings to the community. Additionally, keeping an eye on official Nvidia documentation updates and future Jetpack releases may provide more streamlined methods for implementing custom controls.