[FS#886] Newifi D1 ethernat ports freeze after boot with cable plugin

[LEDE Bugs]

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

User who did this - Qier LU (lvqier) 

Attached to Project - LEDE Project
Summary - Newifi D1 ethernat ports freeze after boot with cable plugin
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - High
Priority - Very Low
Reported Version - lede-17.01
Due in Version - Undecided
Due Date - Undecided
Details - Newifi D1 is a router device with MT7621 inside, more detailed information can be found at [[https://wikidevi.com/wiki/Lenovo_Newifi_D1|WikiDevi]].

I have LEDE 17.01.2 running on the device, but experienced a bug with ethernat port. The bug is easy to reproduce: just **powner on** or **reboot** the device with RJ45 cable plugin. You will find that the LED blinks when booting, but freezes after boot. The frozen status of LED is on(wan port), off(lan port), on(lan port) in my situation which have both 3 ports connected. 

But every thing works fine if I power on/reboot the device first, then plugin the RJ45 cable.

I could not connect to the device via the ethernat when it is frozen, but can login via wireless network provided by the device. I have checked the network status with ifconfig, the RX counter of eth0, eth0.1 and eth0.2 shows 0 when TX counter seems OK if I ping someone. I checked the switch as well by command: swconfig dev mt7530 show , every thing shows 0 on each port, excepted for port 6. No error message on dmesg.

Some one mentioned it is switch chip driver bug: https://dev.openwrt.org/ticket/20890?cversion=0&cnum_hist=1 . But no further information can be find by google any more. 

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=886