Ubuntu 20.04 - add GPU bumps network PCIe address and kills network


I am trying to add a GPU to an Ubuntu 20.04 system and found that when I add the GPU the network interface stops working. I think I have narrowed it down to the fact that the PCIe address of the network adapter is bumped by the GPU VGA and sound interfaces. ‘lspci’ shows me the address changes from 8.00.0 to a.00.0

What can I do? Options I can think of, but don’t know how to implement:

  1. Rescan the hardware (like Windows can)
  2. Remove the ethernet driver/device and add it again

Both of these need to be done from ssh command line, I have not got gnome desktop.

Clues and pointers very welcome!

This article explains how to find which driver is used, and so I wonder if I can then apt remove , then apt install driver ?

Is this a desktop? GPU goes to the PCIe slot, closest to the cpu. I’ve never seen my network change because of a gpu. Maybe something else is going on with your hardware.

It’s not a desktop. It’s a headless server, I do everything with ssh. I’ve got two Nvidia GPUs to run with hashcat to demonstrate why good passwords are important to clients. I think my mistake is to install the GPUs after installing the operating system, and the pcie addressing changes have broken the network.

I tried disabling the Ethernet in the BIOS and starting Ubuntu up (to remove the network config), then shut down, enable it again and start Ubuntu to allow it to add the driver - but it didn’t make any difference. lspci still lists the Ethernet interface (and the GPUs) but no working network.

I looked for information on how Ubunut autodetect the device, but its not well described. Perhaps I need to buy Jay’s book on Mastering Ubuntu.

To be pragmatic - I think I will reinstall Ubuntu fresh with my GPUs connected. I reckon that will work.