TX2, Elroy, PCIe issue

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hi,
I have a TX2 hooked up to an Elroy carrier board. There are two PCIe ports on the Elroy. I am trying to connect a WiFi chip, WPEQ-450AC to the Erloy.

When I connect it to one of the ports, it works just fine. When I connect it to the other port it doesn’t. I noticed that after I connect it to the working port, then swap it to the other one and reboot. I get the folowing errors on boot up. However, I don’t get that with the other port:

thumbnail_IMG_20210309_212757
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And here is dmesg | grep pci
[ 0.435453] GPIO line 459 (pcie0_lane2_mux) hogged as output/low
[ 0.441075] iommu: Adding device 10003000.pcie-controller to group 48
[ 0.441092] arm-smmu: forcing sodev map for 10003000.pcie-controller
[ 0.910931] tegra-pcie 10003000.pcie-controller: 2x1, 1x1, 1x1 configuration
[ 0.912001] tegra-pcie 10003000.pcie-controller: PCIE: Enable power rails
[ 0.912420] tegra-pcie 10003000.pcie-controller: probing port 0, using 2 lanes
[ 0.914609] tegra-pcie 10003000.pcie-controller: probing port 1, using 1 lanes
[ 0.916927] tegra-pcie 10003000.pcie-controller: probing port 2, using 1 lanes
[ 1.100672] ehci-pci: EHCI PCI platform driver
[ 1.100713] ohci-pci: OHCI PCI platform driver
[ 1.324923] tegra-pcie 10003000.pcie-controller: link 0 down, retrying
[ 1.747530] tegra-pcie 10003000.pcie-controller: link 0 down, retrying
[ 2.155531] tegra-pcie 10003000.pcie-controller: link 0 down, retrying
[ 2.157567] tegra-pcie 10003000.pcie-controller: link 0 down, ignoring
[ 2.573560] tegra-pcie 10003000.pcie-controller: link 1 down, retrying
[ 2.989805] tegra-pcie 10003000.pcie-controller: link 1 down, retrying
[ 3.451534] tegra-pcie 10003000.pcie-controller: link 1 down, retrying
[ 3.453578] tegra-pcie 10003000.pcie-controller: link 1 down, ignoring
[ 3.851146] tegra-pcie 10003000.pcie-controller: link 2 down, retrying
[ 4.241558] tegra-pcie 10003000.pcie-controller: link 2 down, retrying
[ 4.631536] tegra-pcie 10003000.pcie-controller: link 2 down, retrying
[ 4.634641] tegra-pcie 10003000.pcie-controller: link 2 down, ignoring
[ 4.940077] tegra-pcie 10003000.pcie-controller: PCIE: no end points detected
[ 4.940418] tegra-pcie 10003000.pcie-controller: PCIE: Disable power rails

lspci returns nothing when connected to the functional port. However, it returns the device name when connected to the functional one.

I know that one solution is to just use the working port. The issue is that I can’t hold the WiFi chip in place with screws in this port. But I can do that with the other non functional port. And holding it in place is pretty important for my application.
Any help appreciated. Thanks

3

Can you please check with the carrier board vendor if both the ports are similar in terms of PCIe sideband signals (i.e. PERST# and CLKREQ#)? The fact that we are observing completion timeouts could possibly be because of differences in the PCIe sideband signal routing

4

Hi 93afandi -

Have you contacted our Tech Team? If you fill out our support form (found here) our team will help you troubleshoot.

Let me know if you have any questions!
Jacki

5

I already sent an email to support@connecttech.com

Thank you

6

The fix is to flip the SW1A on the Elroy to the on position.