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Date:   Thu, 28 Feb 2019 22:54:46 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        linux-arm-kernel@lists.infradead.org,
        Antoine Tenart <antoine.tenart@bootlin.com>,
        thomas.petazzoni@bootlin.com, gregory.clement@bootlin.com,
        miquel.raynal@bootlin.com, nadavh@marvell.com, stefanc@marvell.com
Subject: Re: [PATCH net] net: dsa: mv88e6xxx: power serdes on/off for 10G
 interfaces on 6390X
Message-ID: <20190228215446.GB24085@lunn.ch>
References: <20190228211433.14211-1-maxime.chevallier@bootlin.com>
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On Thu, Feb 28, 2019 at 10:14:33PM +0100, Maxime Chevallier wrote:
> Upon setting the cmode on 6390 and 6390X, the associated serdes
> interfaces must be powered off/on.
> 
> Both 6390X and 6390 share code to do so, but it currently uses the 6390
> specific helper mv88e6390_serdes_power() to disable and enable the
> serdes interface.
> 
> This call will fail silently on 6390X when trying so set a 10G interface
> such as XAUI or RXAUI, since mv88e6390_serdes_power() internally grabs
> the lane number based on modes supported by the 6390, and returns 0 when
> getting -ENODEV as a lane number.
> 
> Using mv88e6390x_serdes_power() should be safe here, since we explicitly
> rule-out all ports but the 9 and 10, and because modes supported by 6390
> ports 9 and 10 are a subset of those supported on 6390X.
> 
> This was tested on 6390X using RXAUI mode.
> 
> Fixes: 364e9d7776a3 ("net: dsa: mv88e6xxx: Power on/off SERDES on cmode change")
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew