Does not recognize the PCIE device

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
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1

Hi,
We are making custom carrier board for the Jetson AGX xavier module.
And we have configured the PCIe ports as below.
1.PCIe x1 (UPHY7 C3 )- Used for WLE900VX7BA(wifi module) in custom carrier board
2.PCIe x4 (UPHY[2:5] C0 )- Used for PEX8615(PCIe switch) in custom carrier board .
When testing the PCIE device, the system did not recognize the device. I measured PEX_CLK0_PIN and PEX_CLK0_PIN, and found that there was only a short clock output during the boot process, which was about 1 second.

Is the PCIE clock signal abnormal due to the failure to recognize the device, or is the PCIE clock signal abnormal due to the failure to recognize the PCIE device?

Can a PCIe device be recognized if it does not have a driver?

Thanks.

3

Hi,
The driver from vendor is not needed if it is just for detecting.
If your device could be seen in the result of command “lspci”, then the hardware signal is fine.

4

It is possible that you are observing REFCLK for only a short period of time because the PCIe link is not up. You can remove “nvidia,enable-power-down;” entry from the respective device-tree node so that the controller would continue to be active even when there is no PCIe link up (current/default behavior is that the controller gets powered down when there is no active PCIe link is found)
What about #PERST routing? do you have it present in the custom designed board?