Description of problem:
After upgrade to TrueNAS SCALE 20.12 only the first Ethernet port in the PCI enumeration for the Intel X5xx with 4 ports is working as expected.
The remaining three ports are no longer available.
This will affect anyone upgrading from TrueNAS SCALE 20.10 to 20.12 and had multiple Ethernet interfaces configured as aggregates or distinct networks. Systems affected use the ixgbe.ko Linux driver module.
The system tested is:
Supermicro A2SDi-8C-HLN4F with Intel X550 1Gbps 4 port Ethernet controller.
32GB ECC registered DDR4 DRAM, 1TB WD BLUE SSD as boot device.
In TrueNAS SCALE 20.10, all 4 Ethernet ports were working as expected on the test system. Also, downgrading to 20.10 from 20.12 has them all working again.
Upgrade Linux kernel to 5.9.15 or later, which has this patch applied to allow the remaining Ethernet ports on the same PHY MDIO address to enumerate correctly:
ixgbe: fix probing of multi-port devices with one MDIO
After install of TrueNAS SCALE 20.12, force taint the incumbent Linux kernel 5.9 with the ixgbe driver built from Linux kernel 5.9.15.