Camera V4L2 Sensor Driver Migration Issues on Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties when migrating their V4L2 camera sensor driver to the Jetpack 6.0 developer preview image on the Jetson Orin Nano Developer Kit. The specific symptoms include:

• Failure to create video and sub-devices: When the camera driver kernel module is inserted, it fails to register the video device and sub-device.
• Debugging output: Users have added debug prints to the v4l2-async.c file, revealing that the driver cannot match the firmware node (fwnode) due to changes in the matching criteria from device name matching to fwnode matching.
• Kernel logs: The logs show that while the camera sensor is detected, it fails to match the fwnode, leading to unsuccessful device registration.

The context of this issue arises during the setup of a new camera device tree overlay file, which involves compiling a Device Tree Source (DTS) file into a Device Tree Blob Overlay (DTBO) and updating configurations in extlinux.conf. The problem is consistently observed across multiple user reports, indicating a significant impact on user experience as it prevents successful integration of camera functionality in applications.

Possible Causes

Several potential causes for this issue have been identified:

• Device Tree Configuration Errors: Incorrect or incomplete device tree overlay files may lead to mismatches in expected node structures, preventing proper registration of devices.

• Driver Compatibility Issues: The transition from older kernel versions to the 5.15 kernel may introduce bugs or incompatibilities in how V4L2 drivers interact with the system.

• Missing Firmware Nodes: If required firmware nodes are not defined in the device tree or if they are incorrectly configured, this could lead to null values being returned during fwnode matching.

• Software Bugs: There may be bugs within the kernel’s V4L2 subsystem that affect how devices are registered and matched.

• User Configuration Errors: Misconfigurations during setup or incorrect application of patches could also contribute to these issues.

Troubleshooting Steps, Solutions & Fixes

To address these issues, users can follow these troubleshooting steps:

1. Verify Device Tree Overlay File:

   • Check for correctness in the DTS file structure and ensure all necessary nodes are defined correctly.
   • Compare with known working examples (e.g., tegra234-p3767-camera-p3768-imx219-A.dts) for reference.

2. Compile and Apply Device Tree Overlay:

   • Use the following command to compile your DTS file:

     dtc -I dts -O dtb -o <output_file>.dtbo <input_file>.dts
     

   • Ensure that the DTBO file is copied correctly to /kernel/dtbo.

3. Update extlinux.conf:

   • Ensure that the DTB filename is correctly updated in extlinux.conf to point to your new device tree.

4. Check Kernel Logs:

   • After attempting to load the driver, check kernel logs using:

     dmesg | grep nvcam
     

   • Look for messages related to fwnode matching failures.

5. Patch Application:

   • If applicable, apply relevant patches as suggested by other users in the forum. For example:

     diff --git a/drivers/media/platform/tegra/camera/camera_common.c b/drivers/media/platform/tegra/camera/camera_common.c
     ...
     

6. Debugging fwnode Matching:

   • Print out fwnode values before matching attempts to identify why matches might be failing:

     printk(KERN_INFO "sd->fwnode: %p\n", sd->fwnode);
     printk(KERN_INFO "asd->match.fwnode: %p\n", asd->match.fwnode);
     

7. Test with Different Configurations:

   • Test with various configurations and known working DTS files to isolate whether the issue lies within your specific setup or if it is a broader compatibility issue.

8. Consult Documentation and Community Resources:

   • Refer to NVIDIA’s official documentation for Jetpack and V4L2 drivers for any updates or known issues.
   • Engage with community forums for shared experiences and solutions.

9. Consider Environmental Factors:

   • Ensure that your power supply and thermal conditions are optimal for operation, as hardware issues can sometimes manifest as software problems.

10. Unresolved Areas:

    • Further investigation may be required regarding specific kernel bugs or additional patches needed for full compatibility with Jetpack 6.0.

By following these steps, users should be able to diagnose and potentially resolve issues related to migrating their V4L2 camera sensor driver on the Jetson Orin Nano Developer Kit.