This topic describes how to use the PCIE x16 slot?

Hello, when using the PCIE x16 of AGX ORI, I meet two problems that I would like to consult.

  1. When no device is connected to the PCIE x16 slot, I find that the development board stops supplying power to the pcie x16 slot after the system is started. I would like to ask if there is any way to keep the PCIE x16 slot supplying power and detecting pcie devices regardless of whether there is any device connected.
  2. When a pcie x16 is connected to a pcie device with a reference clock and power supply enabled, the AGX ORI development board is stuck after it prints only one log message during startup. The log message is as follows: Jetson UEFI firmware (version 3.1-32827747 built on…) What causes this? Is there any solution?


  1. The regulator is disabled because our kernel notices there is no device connected on the slot and do the power saving. It is normal behavior on the kernel 5.10.

  2. Is it tested on devkit or a custom board? Do you have full log to attach?

  1. Can the PCIe plot continue to supply power and how to modify it?
  2. Yes, we use AGX Orin developer kit. When AGX Orin starts, only one log is printed: Jetson UEFI firmware (version 3. 1-32827747 built on.). If there is no other print information, how can I view more print information?

I don’t get what is the point to do (1). We don’t support PCIe hotplug either.

For 2, since where you got stuck is the UEFI, if you want full log, you need to rebuild the UEFI binary and there would be one DEBUG version of binary. Reflash your system with that binary and it will enable full logs in UEFI.

But you have to make sure it is really stuck inside UEFI but not something else. If you cannot tell it, then it better still posting the log here for me to check.

  1. Hello, we need to connect another device through the pcie x16 slot of AGX Orin, and the other device can start normally only after AGX Orin starts and the pcie x16 slot is powered on continuously. Now when AGX Orin is first started, it shows that the pcie connection cannot be detected and the power is automatically cut off. We would like to ask how to turn off this automatic power off function.

  2. As for problem 2, the log information displayed through the serial port is as shown in the figure below because we first supplied power to another device and then started AGX Orin. We did not get a log message text because the system was stuck. This problem is related to the fact that AGX Orin is connected to a PCIE device with power supply. I would like to ask if there is any solution for it?


  1. Your idea may not be the right direction. It is common that a pcie device is not getting detected.
    Please follow this document to debug this.
    Jetson AGX Orin Platform Adaptation and Bring-Up — Jetson Linux Developer Guide documentation
    The “power goes down” is just the result. It is not the cause. Your device cannot link up is not due to the power is missing. It is your device cannot be detected with some reasons so that the power goes off by the kernel.

  2. Yes, it looks like getting stuck in UEFI. You need to enable full log as my previous comment said. We have no solution yet because you didn’t provide any useful information so far.

  3. I actually don’t understand the situation. Does your jetson boot up or not? Does it fail to boot up because of your pcie device?

  1. Hello, how to boot the kernel manually from the command line in UEFI Shell? we found that PCI devices can be detected in UEFI. We want to try some startup kernels and print the output, otherwise it will get stuck.
    2.Jetson Orin does not have a fully boot and will be stuck in the UEFI, and yes, as long as the PCIe device is powered on, it will be stuck, and everything will be fine without connecting the PCIe device.


You should follow my previous comment to enable full UEFI log. I don’t know what startup kernel log you want to add here. The point to get stuck is not in kernel. Adding log to kernel does not help.

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