Validating DisplayPort link on custom carrier

Robotics & Edge Computing Jetson & Embedded Systems Jetson Orin NX
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1

Hello,

We have a custom carrier board for the Orin NX and have gotten DisplayPort over USB-C Alt mode working. Now we are working on automated tests for our manufacturing department to use ensure new boards are working correctly before we ship them.

Is there a tool I can run on the Orin NX to query the GPU or DisplayPort PHY to get some DP link status information? For PCIe devices, we have lspci of course, which tells us things like the number of PCIe lanes and how fast the link is. Is there such a tool for DisplayPort?

As you know, DisplayPort over USB-C can operate in a couple of “pin assignments”. We are supporting pin assignments C, D, and E. Pin assignments C/E connect all 4 lanes of DisplayPort out to the USB-C connector. Pin assignment D only connects 2 displayport lanes to the connector.

I would like to be able to read this kind of information (number of DP lanes active, DP link bandwidth, etc.) from Linux running on the Orin NX if possible.

Thank you.

  • Alex
3

Unfortunately, there is no such tool on Orin platform.

4

Thank you for your reply.

I have tried looking in SysFS for GPU output status information. The best path I found was /sys/class/graphics/fb0/ which has a few files. I don’t understand why the mode file here returns nothing. But at least modes (plural) does have some output that is close to what I am looking for

test@localhost:/sys/class/graphics/fb0$ cat mode
test@localhost:/sys/class/graphics/fb0$ cat modes
U:2560x1440p-0

Do you know if information such as DisplayPort link bandwidth or number of active data lanes is available via SysFS files published by the NVIDIA GPU driver somewhere?

5

I am not sure about why you just repeat your question again when I already told such info does not exist on Orin…

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My first question was asking if there was an application that exists. My follow-up question was about SysFS nodes.

Anyway, for those who may come across this later, it seems nvidia-settings may be able to report information about the connection to the display (number of lanes and bandwidth), but only through the GUI and not through CLI queries. We are looking in to this internally.

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