changing switch port settings fec does not actually changing link fec

[rcgoodfellow]

I changed link fec through the API and it did not take place in dendrite. Only when I deleted the link and let the RPW recreate it did the fec mode get changed

[jgallagher]

Is this related to https://github.com/oxidecomputer/dendrite/issues/588? That one was about autonegotiation, but if the RPW is using apply_port_settings it might have the same root cause.