VLAN 802.1q support for VIM board on Ubuntu 20.04 with st_gmac driver

On a VIM3, with the most current “stable” 4.9 kernel I’ve attempted to configure VLANs using nmcli as one would normally. However, I’ve noticed it’s not working and there is no 8021q kernel module loaded.

E.g. lsmod | grep 8021q does find any loaded modules. And it’s not possible to load it.

# modprobe 8021q
modprobe: FATAL: Module 8021q not found in directory /lib/modules/4.9.241

And when trying to set it up via nmcli, it cannot create the VLAN interface. E.g.

# nmcli con up vlan1-root
Error: Connection activation failed: eth0.1 failed to create resources: Failed to create VLAN interface 'eth0.1' for 'vlan1-root': NME_UNSPEC

How does one get a kernel module included/loaded so that the Ethernet adapter supports VLANs? I read this is possible on a Rasberry PI by installing extra kernel modules. Is there a similar requirement with this board?

The NIC hardware is related to Amlogic Meson DWMAC?