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Date:   Fri, 22 Feb 2019 22:39:53 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Parshuram Thombare <pthombar@cadence.com>
Cc:     nicolas.ferre@microchip.com, davem@davemloft.net,
        netdev@vger.kernel.org, f.fainelli@gmail.com, hkallweit1@gmail.com,
        linux-kernel@vger.kernel.org, rafalc@cadence.com,
        piotrs@cadence.com, jank@cadence.com
Subject: Re: [PATCH 1/3] net: ethernet: add support for PCS and 2.5G speed
Message-ID: <20190222213953.GN5894@lunn.ch>
References: <20190222201225.GA15633@lvlogina.cadence.com>
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>  	/* mask with MAC supported features */
> -	if (macb_is_gem(bp) && bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE)
> -		phy_set_max_speed(phydev, SPEED_1000);
> -	else
> -		phy_set_max_speed(phydev, SPEED_100);
> +	if (macb_is_gem(bp)) {
> +		linkmode_copy(phydev->supported, PHY_GBIT_FEATURES);
> +		if (bp->caps & MACB_CAPS_TWO_PT_FIVE_GIG_SPEED)
> +			linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
> +					 phydev->supported);
> +	} else {
> +		linkmode_copy(phydev->supported, PHY_BASIC_FEATURES);
> +	}
> +
> +	linkmode_copy(phydev->advertising, phydev->supported);

This is not correct. Just because the MAC can do 2.5G does not mean
the PHY can. So you should not be adding links modes. Also, somebody
might be using a PHY that can do 2.5G with a MAC which can only do 1G.

The correct thing to do is call phy_set_max_speed() with the maximum
speed the MAC can do.

      Andrew