no LLDP on Intel X710 NICs

[Haw Loeung]

Hi,

Per the Intel community [1], for Intel X710 controllers, the NIC is meant to handle LLDP directly. Unfortunately, this doesn't play well with lldpd:

| hloeung@cumulus:mgmt:~$ net show lldp | grep swp24
| swp24 10G Trunk/L2 37383638-3530-5A43-3238-333330423954 Unknown

It is known in upstream lldpd[2] with a fix proposed to work around this by disabling handling of LLDP in the NIC[3]. Can we please backport this to Focal?

The suggested workaround is:

| for i in $(sudo ls /sys/kernel/debug/i40e); do
| echo lldp stop | sudo tee /sys/kernel/debug/i40e/${i}/command
| done

[1]https://community.intel.com/t5/Ethernet-Products/X710-dropping-LLDP-frames/m-p/348508
[2]https://github.com/lldpd/lldpd/issues/372
[3]https://github.com/lldpd/lldpd/commit/a74fd8ca9c02fc0eb81f7a219b2bb657cac25ca2