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Date:   Tue, 8 Feb 2022 03:09:48 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Raag Jadav <raagjadav@gmail.com>
Cc:     Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Steen Hegelund <steen.hegelund@microchip.com>,
        Bjarni Jonasson <bjarni.jonasson@microchip.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: phy: mscc: enable MAC SerDes autonegotiation
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> MAC implementation[1] in a lot of NXP SoCs comes with in-band aneg enabled
> by default, and it does expect Clause 37 auto-negotiation to complete
> between MAC and PHY before the actual data transfer happens.
> 
> [1] https://community.nxp.com/pwmxy87654/attachments/pwmxy87654/t-series/3241/1/AN3869(1).pdf
> 
> I faced such issue while integrating VSC85xx PHY
> with one of the recent NXP SoC having similar MAC implementation.
> Not sure if this is a problem on MAC side or PHY side,
> But having Clause 37 support should help in most cases I believe.

So please use this information in the commit message.

The only danger with this change is, is the PHY O.K with auto-neg
turned on, with a MAC which does not actually perform auto-neg? It
could be we have boards which work now because PHY autoneg is turned
off.

      Andrew