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Date:   Mon, 18 Jul 2022 19:28:58 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Sean Anderson <sean.anderson@seco.com>
Cc:     "Russell King (Oracle)" <linux@armlinux.org.uk>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Madalin Bucur <madalin.bucur@nxp.com>, netdev@vger.kernel.org,
        Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <edumazet@google.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Alexandru Marginean <alexandru.marginean@nxp.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>
Subject: Re: [PATCH net-next v3 08/47] net: phylink: Support differing link
 speeds and interface speeds
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> > I am rather worried that we have drivers using ->speed today in their
> > mac_config and we're redefining what that means in this patch.
> 
> Well, kind of. Previously, interface speed was defined to be link speed,
> and both were just "speed". The MAC driver doesn't really care what the
> link speed is if there is a phy, just how fast the phy interface mode
> speed is.

I'm not sure that is true. At least for SGMII, the MAC is passed the
line side speed, which can be 10, 100, or 1G. The PHY interface mode
speed is fixed at 1G, since it is SGMII, but the MAC needs to know if
it needs to repeat symbols because the line side speed is lower than
the host side speed.

     Andrew