netdev - Re: [PATCH net-next] net: phy: at803x: remove at803x_aneg

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Message-ID: <ae201dadd6842f533aaa2e1440209784@walle.cc>
Date:   Thu, 18 Mar 2021 17:38:13 +0100
From:   Michael Walle <michael@...le.cc>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     Vladimir Oltean <olteanv@...il.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH net-next] net: phy: at803x: remove at803x_aneg_done()

Am 2021-03-18 17:21, schrieb Heiner Kallweit:
> On 18.03.2021 16:17, Vladimir Oltean wrote:
>> On Thu, Mar 18, 2021 at 03:54:00PM +0100, Heiner Kallweit wrote:
>>> On 18.03.2021 15:23, Michael Walle wrote:
>>>> at803x_aneg_done() is pretty much dead code since the patch series
>>>> "net: phy: improve and simplify phylib state machine" [1]. Remove 
>>>> it.
>>>> 
>>> 
>>> Well, it's not dead, it's resting .. There are few places where
>>> phy_aneg_done() is used. So you would need to explain:
>>> - why these users can't be used with this PHY driver
>>> - or why the aneg_done callback isn't needed here and the
>>>   genphy_aneg_done() fallback is sufficient
>> 
>> The piece of code that Michael is removing keeps the aneg reporting as
>> "not done" even when the copper-side link was reported as up, but the
>> in-band autoneg has not finished.
>> 
>> That was the _intended_ behavior when that code was introduced, and 
>> you
>> have said about it:
>> https://www.spinics.net/lists/stable/msg389193.html
>> 
>> | That's not nice from the PHY:
>> | It signals "link up", and if the system asks the PHY for link 
>> details,
>> | then it sheepishly says "well, link is *almost* up".
>> 
>> If the specification of phy_aneg_done behavior does not include 
>> in-band
>> autoneg (and it doesn't), then this piece of code does not belong 
>> here.
>> 
>> The fact that we can no longer trigger this code from phylib is yet
>> another reason why it fails at its intended (and wrong) purpose and
>> should be removed.
>> 
> I don't argue against the change, I just think that the current commit
> description isn't sufficient. What you just said I would have expected
> in the commit description.

I'll come up with a better one, Vladimir, may I use parts of the text
above?

-michael