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Date:   Wed, 14 Sep 2022 16:37:48 +0100
From:   "Russell King (Oracle)" <linux@armlinux.org.uk>
To:     Siddharth Vadapalli <s-vadapalli@ti.com>
Cc:     davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
        pabeni@redhat.com, robh+dt@kernel.org,
        krzysztof.kozlowski@linaro.org, krzysztof.kozlowski+dt@linaro.org,
        vladimir.oltean@nxp.com, grygorii.strashko@ti.com, vigneshr@ti.com,
        nsekhar@ti.com, netdev@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kishon@ti.com
Subject: Re: [PATCH 2/8] net: ethernet: ti: am65-cpsw: Add support for SERDES
 configuration
Message-ID: <YyH1TH0UqCzN37J2@shell.armlinux.org.uk>
References: <20220914095053.189851-1-s-vadapalli@ti.com>
 <20220914095053.189851-3-s-vadapalli@ti.com>
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Sender: Russell King (Oracle) <linux@armlinux.org.uk>
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On Wed, Sep 14, 2022 at 03:20:47PM +0530, Siddharth Vadapalli wrote:
> @@ -1427,6 +1471,9 @@ static void am65_cpsw_nuss_mac_link_down(struct phylink_config *config, unsigned
>  	struct net_device *ndev = port->ndev;
>  	int tmo;
>  
> +	/* disable phy */
> +	am65_cpsw_disable_phy(port->slave.ifphy);
> +

This seems really strange. If you have a serdes interface which
presumably supports SGMII, 1000base-X etc, then link status is sent
across the serdes interface. If you power down the serdes, then you
can't receive the link status, and so mac_link_up() won't be called.

Are you really sure you want to be enabling and disabling the PHY
in mac_link_down()/mac_link_up() ?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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