[FS#949] mt7620/1/8 ethernet link states inconsistent

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Alex Maclean (eamaclean) 

Attached to Project - LEDE Project
Summary - mt7620/1/8 ethernet link states inconsistent
Task Type - Bug Report
Category - Kernel
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - On the MT7620, initial state of eth0 is always UNKNOWN with carrier up. If booted with no cable, attaching and detaching will flip to state DOWN and no carrier, and if booted with a cable attached, detaching does the same. I'd swear to seeing it get stuck in UNKNOWN, but I'm having trouble reproducing that.

On the MT7621 and MT7628 devices, link state is always UNKNOWN and carrier up - no response to cable attach and detach is seen no matter the initial cable state.

Test devices are a GLi MT300N (MT7620N), TP-Link RE350 (MT7621A), and UniElec 7628N-01 (MT7628NN, this is not in-tree, it's a small module I'm toying with).

This causes issues with, for example, netdev LED triggers.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=949