Total USB Bandwidth of Jetson Orin Nano’s 4 USB Ports

Issue Overview

Users are seeking clarification on the total USB bandwidth available for the four USB 3.2 ports on the Jetson Orin Nano Developer Kit. There is confusion about the actual bandwidth capacity due to the connection of these ports to a single USB 3.1 hub, which is then connected to a USB port on the module labeled as USB 2.0. This ambiguity has led to questions about whether the total bandwidth is limited to USB 2.0 speeds (480 Mbps) or if it can achieve the full USB 3.2 bandwidth of 10 Gbps.

Possible Causes

1. Misinterpretation of hardware specifications: Users may be misunderstanding the relationship between the USB ports, the hub, and the module’s USB connection.

2. Unclear documentation: The labeling of the module’s USB port as USB 2.0 may be causing confusion about the actual capabilities of the system.

3. Potential hardware limitations: There could be actual limitations in the hardware design that affect the total bandwidth available across all ports.

Troubleshooting Steps, Solutions & Fixes

1. Understand the correct specifications:

   • The 4 USB Type-A ports on the Jetson Orin Nano Developer Kit are connected to an embedded USB hub, which is then connected to a USB 3.2 root hub (USBSS0).
   • The total theoretical bandwidth for these 4 USB ports is 10 Gbps.

2. Be aware of USB 2.0 device limitations:

   • If you connect a USB 2.0 device to any of the ports, that specific port will be limited to 480 Mbps.
   • This limitation does not affect the other ports, which can still operate at USB 3.2 speeds.

3. Verify the hardware design:

   • Refer to the official Jetson Orin Nano Developer Kit Carrier Board Specification document for accurate information about the USB connections.
   • The document shows that J6 and J7 (which likely correspond to the USB ports) are physically connected to USB3 pins 161, 163, 166, and 168.

4. Understand the root hub configuration:

   • The USBSS0 mentioned in the hardware diagram is the USB3 root hub, confirming that the ports are indeed capable of USB 3.2 speeds.

5. Test the actual bandwidth:

   • To verify the real-world performance, connect high-speed USB 3.2 devices to multiple ports simultaneously and measure the data transfer rates.
   • You can use tools like iperf or large file transfers to test the bandwidth.

6. Monitor USB bandwidth:

   • For detailed USB bandwidth monitoring, you may need to enable USB monitoring in the kernel.
   • If usbmon is not available, you might need to rebuild the kernel with CONFIG_USB_MON=y.
   • Alternatively, look for other USB monitoring tools compatible with the Jetson Orin Nano’s ARM architecture.

7. Optimize USB performance:

   • Ensure you’re using high-quality USB 3.2 cables to connect your devices.
   • Update to the latest JetPack version to ensure you have the most recent USB drivers and optimizations.
   • If experiencing issues with multiple high-bandwidth devices, try connecting them to different USB controllers if available (e.g., using the USB-C port in addition to the Type-A ports).

8. Consult official resources:

   • For the most up-to-date and accurate information, always refer to the official NVIDIA Jetson documentation and specifications.
   • If you encounter persistent issues or have further questions, consider reaching out to NVIDIA’s developer support forums for assistance.

By following these steps and understanding the actual hardware configuration, users can properly utilize the full USB 3.2 bandwidth capabilities of the Jetson Orin Nano Developer Kit, which offers a total theoretical bandwidth of 10 Gbps across its USB ports.