linux-kernel - Re: [RFC] net: dsa: slave: Advertise correct EEE capabilities at slave PHY setup

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Message-ID: <1a3342eb-5a0f-486d-90af-4e052760cf7b@lunn.ch>
Date:   Wed, 31 May 2023 14:56:28 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Lukasz Majewski <lukma@...x.de>
Cc:     "Russell King (Oracle)" <linux@...linux.org.uk>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC] net: dsa: slave: Advertise correct EEE capabilities at
 slave PHY setup

> Thanks for the detailed explanation.
> 
> With "switch" setup - where I do have MAC from imx8 (fec driver)
> connected to e.g. mv88e6071 with "fixed-link", I do guess that the EEE
> management is done solely in mv88e6071?

So you have the MAC-MAC connection? No back to back PHYs in the
middle. If there is no PHY, linux will not do anything with EEE. What
happens will depend on the reset defaults of the switch. For the FEC
phy_eee_init() will return false, so i expect EEE is disabled.

> In other words - the mv88e6071 solely decides if its internal PHY shall
> signal EEE to the peer switch.

Handling EEE in the mv88e6xxx driver is something on my todo list. But
i don't expect it to happen soon. And before it will happen we
actually need to decide how the user API should work.

	Andrew