netdev - Re: [BUG] mv88e6xxx: tx regression in v5.3

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Date:   Thu, 12 Dec 2019 10:50:45 +0200
From:   Baruch Siach <baruch@...s.co.il>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Vivien Didelot <vivien.didelot@...il.com>, netdev@...r.kernel.org,
        Denis Odintsov <d.odintsov@...viangames.com>,
        Hubert Feurstein <h.feurstein@...il.com>
Subject: Re: [BUG] mv88e6xxx: tx regression in v5.3

Hi Andrew,

On Wed, Dec 11, 2019 at 06:49:38PM +0100, Andrew Lunn wrote:
> > Bisect points at 7fb5a711545d ("net: dsa: mv88e6xxx: drop adjust_link to
> > enabled phylink"). Reverting this commit on top of v5.3.15 fixes the
> > issue (and brings the warning back). As I understand, this basically
> > reverts the driver migration to phylink. What might be the issue with
> > phylink?
> 
> That suggests the MAC is wrongly running at 1G, and the PHY at 100M,
> which is why it does not work.

I reproduced the same issue with 1Gb link as well:

[   63.510782] mv88e6085 f412a200.mdio-mii:04 lan1: Link is Up - 1Gbps/Full - flow control rx/tx
[   63.519357] IPv6: ADDRCONF(NETDEV_CHANGE): lan1: link becomes ready

> You probably want to add #define DEBUG to the top of phylink.c, and
> scatter some debug prints in mv88e6xxx_mac_config(). My guess would
> be, either mv88e6xxx_mac_config() is existing before configuring the
> MAC, or mv88e6xxx_port_setup_mac() has wrongly decided nothing has
> changed and so has not configured the MAC.

As you guessed, mv88e6xxx_mac_config() exits early because 
mv88e6xxx_phy_is_internal() returns true for port number 2, and 'mode' is 
MLO_AN_PHY. What is the right MAC/PHY setup flow in this case?

Thanks,
baruch

-- 
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