HDMI Not Working on Custom Jetson Orin Nano Carrier Board

Issue Overview

Users have reported issues with HDMI output on custom carrier boards designed for the Jetson Orin Nano module. The main symptoms include:

• No HDMI output signal
• HDMI port showing as disconnected in software (xrandr)
• No screen display when connecting an HDMI monitor

The custom carrier board differs from the reference design (P3768-0000) in two key aspects:

1. It lacks an EEPROM
2. It uses an HDMI port instead of DisplayPort (DP)

This issue occurs after flashing the board with JetPack 5.1.2 and making HDMI-related modifications. The problem persists even after reflashing the module.

Possible Causes

1. Incorrect software configuration: The Orin Nano is configured for DP out of the box, and HDMI support may not be properly enabled.

2. Pinmux settings: Incorrect pinmux configuration for the HDMI pins, particularly the hotplug detect (HPD) pin.

3. Incomplete software updates: Display software may need updates in both QSPI and additional storage.

4. Hardware incompatibility: The custom carrier board design may have compatibility issues with the Orin Nano module.

5. Driver issues: HDMI drivers may not be properly loaded or configured.

6. GPIO configuration: The HPD GPIO pin may not be properly enabled or configured.

Troubleshooting Steps, Solutions & Fixes

1. Flash with p3509+p3767 configuration:
   Use the following command to flash your board:

   sudo ./tools/kernel_flash/l4t_initrd_flash.sh --external-device mmcblk1p1 -c tools/kernel_flash/flash_l4t_external.xml -p "-c bootloader/t186ref/cfg/flash_t234_qspi.xml" --showlogs --network usb0 p3509-a02+p3767-0000.conf internal
   

   This configuration includes necessary software patches for HDMI support.

2. Verify pinmux settings:
   Check the HDMI pinmux file (tegra234-mb1-bct-pinmux-p3767-hdmi-a03.dtsi) to ensure it matches your custom board’s schematics.

3. Check HDMI hotplug detection:
   Monitor the UART console output when plugging in the HDMI cable. You should see messages related to tegra186_gpio_irq when hotplugging the cable.

4. Examine system logs:
   Collect and analyze the following logs for troubleshooting:

   • dmesg output
   • Xorg.0.log
   • Boot log from UART console

5. Verify software updates:
   Ensure that both QSPI and additional storage have been updated with the latest display software. You may need to perform a full flash, including QSPI, rather than just an initrd flash.

6. Check GPIO configuration:
   Although /sys/kernel/debug/gpio may not show the HPD pin, verify its configuration in the device tree (/proc/device-tree/).

7. Test with reference hardware:
   If possible, test the Orin Nano module on the original developer kit carrier board to isolate whether the issue is with the module or the custom carrier board.

8. Verify HDMI cable and monitor compatibility:
   Test with different HDMI cables and monitors to rule out compatibility issues.

9. Check for kernel messages:
   Look for HDMI-related messages in the kernel log, particularly during boot and when connecting the HDMI cable.

10. Consult NVIDIA documentation:
    Review the Jetson Linux Developer Guide for any specific instructions on enabling HDMI for custom carrier boards.

If the issue persists after trying these steps, consider reaching out to NVIDIA developer support with detailed logs and your custom carrier board schematics for further assistance.