netdev - Re: [PATCH net-next] net: phy: improve link partner capability detection

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Message-ID: <6cc85416-5ccd-ec90-ede5-11d9cfa298b3@gmail.com>
Date:   Fri, 5 Apr 2019 14:11:47 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Heiner Kallweit <hkallweit1@...il.com>,
        Andrew Lunn <andrew@...n.ch>
Cc:     David Miller <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next] net: phy: improve link partner capability
 detection

On 4/5/19 1:51 PM, Heiner Kallweit wrote:
> On 05.04.2019 22:43, Andrew Lunn wrote:
>>> Right. BMSR_ESTATEN should not be set on a Fast PHY. Handling of this
>>> case didn't change.
>>>
>>>> A Fast MAC connected to a Giga PHY. The MAC driver will of used
>>>> phy_set_max_speed() to indicate its limits. In that case, MII_STAT1000
>>>> does exist and we should report what the peer is advertising.
>>>>
>>> That's what we're doing now with this patch.
>>
>> Hi Heiner
>>
>> What i don't get is why we need to do anything based on the MAC. All
>> we need to do is look at BMSR_ESTATEN, and from that decided if we
>> should look at MII_STAT1000 or not. When reporting what the peer can
>> do, we should not care what the local MAC can do.
>>
> Do we have a misunderstanding? What you describe is exactly what we're
> doing now. BMSR_ESTATEN is read by genphy_read_abilities().
> I just don't want to read BMSR whenever genphy_read_status() is called.

You have to read the BMSR to determine the link status anyway, did you
mean: have to check BMSR_ESTATEN whenever genphy_read_status() is called?
-- 
Florian