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Date:   Sat, 18 Apr 2020 16:27:58 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Florian Fainelli <f.fainelli@gmail.com>
Cc:     David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        Heiner Kallweit <hkallweit1@gmail.com>, fugang.duan@nxp.com,
        Chris Healy <Chris.Healy@zii.aero>
Subject: Re: [PATCH net-next v2 3/3] net: ethernet: fec: Allow the MDIO
 preamble to be disabled
Message-ID: <20200418142758.GC804711@lunn.ch>
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> This is a property of the MDIO device node and the MDIO bus controller as
> well, so I would assume that it has to be treated a little it like the
> 'broken-turn-around' property and it would have to be a bitmask per MDIO
> device address that is set/clear depending on what the device support. If it
> is set for the device and your controller supports it, then you an suppress
> preamble.

Again, i don't see how this can work. You need all the devices on the
bus to support preamble suppression, otherwise you cannot use it. As
with a maximum clock frequency, we could add the complexity to check
as bus scan time that all devices have the necessary property, but i
don't think it brings anything.

    Andrew