Workstation reboots after RTL8111G-based GigE network interface is brought up

Hi,

We have a few Z8 G4 workstations, and we've previously been using Intel-based NICs, which work fine in our set up.

However, when we try to use Realtek NICs, after the link is brought up, the system reboots. This issue seems present across BIOS and (Linux) kernel versions, and is reliably reproducable independent of PCIe slot for the card and the few BIOS setting tweaks we've tried.

Steps to reproduce:

1. Install the quad-port PCIe NIC into the motherboard as normal
2. Boot the system without anything in the Ethernet ports of the card
3. When the system is up, bring the interface up by plugging something into an Ethernet port or via the command line
4. The system will reboot -- no kernel messages are logged

We're really scratching our heads here, any help would be greatly appreciated.

[ Side-note: we've tested these cards in other machines, where they work as expected ]

System information:

CPU:       2x Xeon Gold 6136 (24c/48t) @ 3.00GHz
Memory:    96G ECC RDDR4
Boot disk: 256G NVMe
BIOS:      P60 v01.67 08/15/2018

And the network card:

Part #:  ST1000SPEX43
Chipset: Realtek RTL8111G