[FS#1352] ar71xx/mikrotik: Link change detection on switch ports no longer working for some devices

[LEDE Bugs]

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

User who did this - João Chainho (joaochainho) 

Attached to Project - OpenWrt/LEDE Project
Summary - ar71xx/mikrotik: Link change detection on switch ports no longer working for some devices
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 - Link change detection on switch ports no longer working for some MikroTik devices, such as:
- RB493G (AR8316 switch)
- RB951G-2HnD (AR8327 switch)

Can't tell if this is specific to MikroTik devices or if it also affects other AR8xxx switch based ones.
This was working in the past (old OpenWrt r46741), but I can't tell when or how long it stopped working.


[  157.486354] Atheros AR8216/AR8236/AR8316 gpio:00: Port 4 is down
[  161.505826] Atheros AR8216/AR8236/AR8316 gpio:00: Port 4 is up
[  240.890350] Atheros AR8216/AR8236/AR8316 ag71xx-mdio.0:00: Port 3 is down
[  242.900237] Atheros AR8216/AR8236/AR8316 ag71xx-mdio.0:00: Port 3 is up


Initial commit for link change detection support:
https://github.com/openwrt/openwrt/commit/a1fba9dfbe628b171ac789510aca233178fe7d85

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1352