Subject: Re: i.MX6S/DL and QCA8334 switch using DSA driver - CPU port not working

From: Andrew Lunn <[email-masked]>
Date: Fri, 4 May 2018 15:30:14 +0200

> Some RGMII delay tunning attempts with v4.17-rc2:
> 
> phy-mode (fec)	Rx/Tx delay	result
> --------------------------------------
> rgmii		0/0		NOT OK
> rgmii		1/1		NOT OK
> rgmii		2/2		NOT OK
> rgmii		3/3		NOT OK
> rgmii-id	0/0		NOT OK
> rgmii-id	1/1		NOT OK
> rgmii-id	2/2		NOT OK
> rgmii-id	3/3		NOT OK
> 
> I am out of ideas how to further debug this.
> Any additional adivce will be much appreciated.

I would suggest looking at the statistics counters.  ethtool -S. Try
it for both the slave interfaces, and the master interface. The master
interfaces statistics should have both the host counters, and the
switches counters. Do you see packets being sent but not received? Are
there errors reported?

      Andrew