USB-C DisplayPort Configuration Issues on Nvidia Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties with configuring USB-C as a DisplayPort on the Nvidia Jetson Orin Nano Dev board, particularly when using a custom carrier board. The main symptoms include:

• Display Recognition Failure: After booting into the kernel stage, the system does not recognize the DisplayPort connection, and the status in /sys/class/drm/card0-DP-1/status is marked as "disconnected."

• Successful UEFI Display: The UEFI environment can successfully display on the DisplayPort, indicating that the hardware may be functioning correctly during this stage.

The issue arises specifically during the transition from UEFI to kernel mode, suggesting potential problems with device tree configurations or driver support.

Relevant Specifications

• Custom Carrier Board: Based on Jetson Orin Nano.
• Components Used: TUSB1046 and TPS65988 PD control for USB-C.
• Display Connection: DP1 Pins are assigned for DisplayPort, while DP0 is unassigned.

The frequency of this issue appears to be consistent among users attempting similar configurations, significantly impacting their ability to utilize DisplayPort functionality effectively.

Possible Causes

Several potential reasons could lead to the observed problem:

• Lack of Support for USB-C as DisplayPort: There may be inherent limitations in the Jetson Orin architecture regarding USB-C support for DisplayPort, as indicated by user replies.

• Device Tree Misconfiguration: Incorrect settings in the device tree could prevent proper recognition of the DisplayPort during kernel boot.

• Driver Issues: The relevant drivers may not be fully compatible or may require specific configurations to recognize the DisplayPort connection.

• Hot Plug Detect (HPD) Pin Issues: Users are attempting to disable HPD pins, which could lead to further complications in detecting connected displays.

• Firmware Limitations: The DCE firmware responsible for handling display connections may not be open source or accessible for modifications, limiting user control over display detection processes.

Troubleshooting Steps, Solutions & Fixes

To address the issues with USB-C as a DisplayPort on the Nvidia Jetson Orin Nano Dev board, follow these troubleshooting steps:

1. Verify Device Tree Configuration:

   • Ensure that the device tree is correctly configured for USB-C as DisplayPort. Refer to documentation specific to your carrier board and make necessary adjustments.
   • Example command to view device tree settings:

     dtc -I fs /proc/device-tree > device_tree.dts
     

2. Check Driver Compatibility:

   • Confirm that you are using the latest drivers compatible with your hardware configuration. Update drivers if necessary.

3. Disable Hot Plug Detect (HPD):

   • To disable HPD, you can modify your kernel parameters. This may involve editing configuration files or using specific commands.
   • Example command to disable HPD:

     echo 0 > /sys/class/drm/card0-DP-1/hpd
     

4. Manually Trigger Hot Plug Events:

   • Use udevadm commands to manually trigger hot plug detection events. This can help simulate connection/disconnection scenarios.
   • Example command:

     udevadm trigger --subsystem-match=drm
     

5. Test with Different Configurations:

   • If possible, test with different hardware setups or configurations to isolate whether the issue is hardware-related or software-related.

6. Consult Documentation and Community Forums:

   • Review Nvidia’s official documentation for any updates regarding USB-C and DisplayPort support.
   • Engage with community forums for additional insights or shared experiences from other users facing similar issues.

7. Monitor Firmware Updates:

   • Keep an eye on firmware updates from Nvidia that might address known bugs related to display connectivity.

Note

Some users have reported success with modifying device tree settings and ensuring driver compatibility as effective solutions. Further investigation into DCE firmware limitations may also be necessary, given its closed-source nature.