Using PCIe x2 Switch on Nano

Robotics & Edge Computing Jetson & Embedded Systems Jetson Nano
1

Hi,

We would like to use a PCIe x2 switch on the PCIE0 port. Is it possible?
Lane0 and Lane1 are planned to be used in our design. But we are sure if they can work or not.

PCIE0_Signal
PCIE0_Signal1269×672 88.5 KB

We discovered that the PCIe driver does not seem to support PCIe x2.
We didn’t find “pcie-x2” setting in the kernel/kernel-4.9/drivers/phy/tegra/xusb-tegra210.c.

static const char *tegra210_pcie_functions[] = {
        "pcie-x1",
        "xusb",
        "sata",
        "pcie-x4",
};

PCIe x4 switch is already verified under our test. To save our cost, we would like to lower the number of used lanes because we only need two PCIe end points in some of our products. Please kindly help us check the possibility.

3

You can continue to configure it for x4 mode and connect an x2 PCIe switch and things should just work.

4

Hi vidyas,

Thank you for your help.
By the way, how do we make sure the mode is actually x2 or x4 when system is running? Is there any Linux command or log for checking this?

5

sudo lspci -vvvv can be used to check the link width that got established with the endpoint.

6

Hi vidyas,

Thank you for your great help.