netdev - Re: [PATCH net 2/2] net: phy: Use C45 Helpers in PHY

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Date:   Mon, 4 Mar 2019 15:07:24 +0000
From:   Jose Abreu <jose.abreu@...opsys.com>
To:     Andrew Lunn <andrew@...n.ch>, Jose Abreu <jose.abreu@...opsys.com>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Joao Pinto <joao.pinto@...opsys.com>,
        Heiner Kallweit <hkallweit1@...il.com>
Subject: Re: [PATCH net 2/2] net: phy: Use C45 Helpers in PHY_FORCING state

Hi Andrew,

On 3/1/2019 1:53 PM, Andrew Lunn wrote:
> On Fri, Mar 01, 2019 at 11:54:24AM +0100, Jose Abreu wrote:
>> +static inline int phy_update_link(struct phy_device *phydev)
>> +{
>> +	if (!phydev->drv)
>> +		return -EIO;
>> +
>> +	if (phydev->drv->read_status)
>> +		return phydev->drv->read_status(phydev);
>> +	else if (phydev->is_c45)
>> +		return gen10g_read_status(phydev);
>> +	else
>> +		return genphy_update_link(phydev);
>> +}
> 
> Hi Jose
> 
> The asymmetry here could be an issue.  We might fall into the trap
> that a c45 PHY has the full state in phydev updated, were as a c22
> only has the link updated. Somebody testing on C45 might miss a bug
> for a C22 device.

Notice that this phy_update_link() is called from PHY_FORCING
state which in my case happens when autoneg is not enabled / is
not supported.

I think it makes sense, in this case, to only update link status,
no ?

Thanks,
Jose Miguel Abreu

> 
> Maybe this should be called phy_read_state(), and calls
> genphy_read_status() not genphy_update_link().
> 
>      Andrew
>