I have an old Sony vaio notebook.
It is using sky2 for the built-in NIC.
After suspend by, systemctl suspend, and resume by pressing a key. The NIC link on the notebook side is still reported as down. But from the Switch side, the link is up and link speed is reported as 1000.
After a reboot, systemctl reboot, NIC is working fine.
So after resume from suspend, I need to do:
rmmod sky2 modprobe sky2
to resume the link
ps. Wifi is working fine on resume.