Connecting a PCIe card to to the M.2 Key M slot

We wish to get an additional PCIe slot out of our AGX Xavier Developer Kit, and so purchased an M.2 to PCIe adapter ( Here’s a picture of it installed, if anyone’s curious:

We’ve powered up both the Xavier and the M.2 to PCIe adapter, but no PCIe cards installed into this new slot are detected. We’ve connected the same adapter to a regular Linux desktop, and found that PCIe cards are detected without any configuration necessary.

Does the Xavier require any configuration to detect arbitrary PCIe devices on its M.2 slot? Our L4T version is 32.2.3, with JetPack 4.2.3.

I assume that you have powered up the slot from an external power source (using the yellow,red,black cables shown in the pic). If not, please do that. Apart from that, I don’t think there is anything else required. To understand what is going on better, I think you need to probe the signals. You can start with simple ones like PERST first and then REFCLK and then finally with a protocol analyzer. But, probing PERST and REFCLK should tell us any issue that may exist.

Turns out it was a physical issue. The M.2 side of the adapter had these protruding pieces that behaved as a fulcrum, lifting the pins out of the M.2 slot when the heat sink pressed down on it.

Thank you for your help!