Subject: Re: bug: net: dsa: mv88e6xxx: serdes Unable to communicate on fiber with vf610-zii-dev-rev-c

From: Marek Behun <[email-masked]>
Date: Sat, 18 Jul 2020 17:22:44 +0200

On Sat, 18 Jul 2020 17:05:14 +0200
Andrew Lunn <[email-masked]> wrote:

> > If the traces were broken between the fiber module and the SERDES, I
> > should not see these counters incrementing.  
> 
> Plus it is reproducible on multiple boards, of different designs.
> 
> This is somehow specific to the 6390X ports 9 and 10.
> 
>      Andrew

Hmm.

What about the errata setup?
It says:
/* The 6390 copper ports have an errata which require poking magic
 * values into undocumented hidden registers and then performing a
 * software reset.
 */
But then the port_hidden_write function is called for every port in the
function mv88e6390_setup_errata, not just for copper ports. Maybe Chris
should try to not write this hidden register for SerDes ports.

Marek