Date:   Fri, 10 Mar 2023 11:48:52 +0100
From:   =?UTF-8?B?S8O2cnk=?= Maincent <kory.maincent@bootlin.com>
To:     Vladimir Oltean <vladimir.oltean@nxp.com>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>, netdev@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-omap@vger.kernel.org,
        Michael Walle <michael@walle.cc>,
        Maxime Chevallier <maxime.chevallier@bootlin.com>,
        Richard Cochran <richardcochran@gmail.com>,
        thomas.petazzoni@bootlin.com, Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Jay Vosburgh <j.vosburgh@gmail.com>,
        Veaceslav Falico <vfalico@gmail.com>,
        Andy Gospodarek <andy@greyhouse.net>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com, Minghao Chi <chi.minghao@zte.com.cn>,
        Jie Wang <wangjie125@huawei.com>,
        Oleksij Rempel <linux@rempel-privat.de>,
        Sean Anderson <sean.anderson@seco.com>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Alexander Lobakin <alexandr.lobakin@intel.com>,
        Marco Bonelli <marco@mebeim.net>
Subject: Re: [PATCH v3 3/5] net: Let the active time stamping layer be
 selectable.
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Hello Vladimir,

On Thu, 9 Mar 2023 01:03:21 +0200
Vladimir Oltean <vladimir.oltean@nxp.com> wrote:

> (trimmed CC list of bouncing email addresses)
 =20
Thanks, I will be more careful on next patch series version.
=20
> From previous discussions, I believe that a device tree property was
> added in order to prevent perceived performance regressions when
> timestamping support is added to a PHY driver, correct?

Yes, i.e. to select the default and better timestamp on a board.
=20
> I have a dumb question: if updating the device trees is needed in order
> to prevent these behavior changes, then how is the regression problem
> addressed for those device trees which don't contain this new property
> (all device trees)?

On that case there is not really solution, but be aware that
CONFIG_PHY_TIMESTAMPING need to be activated to allow timestamping on the P=
HY.
Currently in mainline only few (3) defconfig have it enabled so it is really
not spread, maybe I could add more documentation to prevent further regress=
ion
issue when adding support of timestamp to a PHY driver.

Regards,
K=C3=B6ry