JetPack 6.0 I2C-Mux Channel ID Differences in Orin Nano Devkit

Issue Overview

Users are experiencing discrepancies in the I2C-mux channel IDs when transitioning from JetPack 5.1.2 to JetPack 6.0 on the Nvidia Jetson Orin Nano Devkit. Specifically, the channel IDs for I2C buses 9 and 10 have switched, leading to confusion and potential functionality issues with connected sensors. In JetPack 5.1.2, the mapping is as follows:

• I2C-9: i2c-mux (chan_id 0)
• I2C-10: i2c-mux (chan_id 1)

In contrast, JetPack 6.0 presents:

• I2C-9: i2c-mux (chan_id 1)
• I2C-10: i2c-mux (chan_id 0)

This issue arises during setup and operation of CSI cameras and affects users who rely on consistent channel mapping for their applications. The problem has been reported consistently across multiple users, indicating potential regression or design changes in the software.

Possible Causes

1. Software Bugs or Conflicts: Changes in the I2C driver or kernel updates could lead to altered channel mappings.

   • This could result from differences in how JetPack 6.0 handles I2C devices compared to its predecessor.

2. Configuration Errors: Users may not have updated their configurations to align with the new mappings introduced in JetPack 6.0.

   • Incorrect configuration can lead to miscommunication between the device and the software.

3. Driver Issues: The drivers for camera modules may not be fully compatible with JetPack 6.0.

   • This incompatibility can prevent proper initialization and operation of connected sensors.

4. User Errors or Misconfigurations: Users might not be aware of the changes in channel IDs and continue using outdated configurations.

   • This can lead to confusion and troubleshooting difficulties.

5. Environmental Factors: Power supply inconsistencies or thermal issues may exacerbate communication problems.

   • Such factors can affect device performance and reliability.

Troubleshooting Steps, Solutions & Fixes

1. Verify Channel Mapping:

   • Use the command i2cdetect -l to confirm current I2C adapter mappings.
   • Compare outputs from both JetPack versions to identify discrepancies.

2. Update Configuration Files:

   • Modify your application or driver configuration to reflect the new channel IDs:

     # Example modification in configuration file
     # Change from
     i2c-mux-chan_id=0
     # To
     i2c-mux-chan_id=1
     

3. Reinstall or Update Drivers:

   • Ensure that you are using the latest drivers compatible with JetPack 6.0.
   • Check Nvidia’s documentation for any available updates or patches.

4. Testing Different Configurations:

   • Temporarily switch back to JetPack 5.1.2 if possible to verify if the issue persists.
   • This can help isolate whether the problem is specific to JetPack 6.0.

5. Enable CSI Trace Logging:

   • To diagnose issues further, enable CSI trace logging with the following commands:

     sudo su
     modprobe rtcpu_debug
     echo 1 > /sys/kernel/debug/tracing/tracing_on
     echo 30720 > /sys/kernel/debug/tracing/buffer_size_kb
     echo 1 > /sys/kernel/debug/tracing/events/tegra_rtcpu/enable
     echo 1 > /sys/kernel/debug/tracing/events/freertos/enable
     echo 3 > /sys/kernel/debug/camrtc/log-level
     echo 1 > /sys/kernel/debug/tracing/events/camera_common/enable
     echo > /sys/kernel/debug/tracing/trace
     cat /sys/kernel/debug/tracing/trace
     

6. Consult Documentation and Community Forums:

   • Refer to Nvidia’s official documentation for any notes regarding changes between JetPack versions.
   • Engage with community forums for shared experiences and solutions.

7. Report Unresolved Issues:

   • If issues persist after troubleshooting, consider reporting them on Nvidia’s developer forums for further assistance.

8. Best Practices for Future Prevention:

   • Always check release notes when upgrading software versions.
   • Maintain backups of configurations before making significant changes.

By following these steps, users should be able to address the discrepancies in I2C-mux channel IDs effectively while ensuring their systems remain functional with the latest software updates.