RE: Microchip PoE to USB-C®︎ Power and Data Adapter RoadTest Review Data Success

colporteur — Mon, 21 Jun 2021 23:45:40 GMT

[mention:ef601b47037147bfb9b0b4a3ab63026a:e9ed411860ed4f2ba0265705b8793d05] response(s) to my post Insight into lan78xx driver support for Pi motivated me to step back and take a closer look at the environment with the hope of sharpening my skills and possibly make it easier for someone else.

With the PoE injector plugged into one end of the cat cable and the other end of the cat cable plugged into the Microchip PoE, the version of Pi4B I've deployed powered up once the USB-C connector was plugged in. No issues with power. With the USB-C plugged in, the green indicator on the vendor cable came on.

With the Pi4B powered up after a fresh install of the operating system, I issued four commands to inspect the environment.

lsusb: check usb devices

dmesg: to check for lan driver support

ip a: check for any new interfaces

lsmod|grep lan*: for driver modules.

The link/act LED on the Microchip PoE is OFF.

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Command output after configure otg_mode=1 and rebooting the Pi

lsusb: additional usb information

dmesg: additional lan driver information

ip a: additional interface eth1 appears with dhcp configuring the interface with an IP

lsmod|grep lan*: no change.

The link/act LED on the Microchip PoE is ON.

When the network cable connecting the PoE injector to the switch was removed, the link/act LED on the Microchip PoE went off OFF and the eth1 interface losts it IP address.

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lui_gough down plays his experience "I am somewhat familiar with Linux and device driver issues (eugh)." I credit his rapid solution (along with my envy) to his experience. Knowing what to look for, knowing what it means and knowing what to do about it, are the trifecta of skills for troubleshooting.