Jetson AGX Orin PCIe x8 lane bifurcation to 2× x4 — supported or need a PCIe switch?a

Robotics & Edge Computing Jetson Systems Jetson AGX Orin
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1

Hi everyone,
I’m relatively new to Jetson boards, but I have a strong PCB design background.

I’m trying to figure out whether Jetson AGX Orin supports PCIe lane bifurcation on an x8 root port into 2× x4. I couldn’t find a clear statement in the public datasheets / documentation that explicitly confirms x8 → 2× x4 bifurcation support.

My questions:

  1. Does Jetson AGX Orin (module / SoC) support native bifurcation of an x8 PCIe controller into 2× x4 endpoints?

  2. If yes: is this configured via device tree / firmware / boot settings (and are there any reference examples)?

  3. If not: do I need an external PCIe switch / bifurcation chip to split one x8 link into 2× x4?

Use case: I want to route an x8 interface from the module to two independent x4 slots/devices on a custom carrier board.

Any guidance or pointers to the correct NVIDIA documentation would be appreciated. Thanks!

2

Hello,

Thanks for visiting the NVIDIA Developer Forums.
To ensure better visibility and support, I’ve moved your post to the Jetson category where it’s more appropriate

Cheers,
Tom

5

Please refer to the supported PCIe mappings in Tables 7-4, 7-5, and 7-6 in the Jetson AGX Orin Series Design Guide (including AGX Orin Industrial).

You could use the x4 on controller C4 and either of the x8 on C5 or C7 in x4 mode. Neither of the two x8 configurations can be split into two x4 directly from AGX Orin, so you would need to externally handle the bifurcation as you mentioned in #3.