Message-ID: <0a1ec04fe494fcd8c68d03e4f544d7162c0e4f39.camel@gmail.com>
Subject: Re: [PATCH net-next v2 4/6] net: mdio: scan bus based on bus
 capabilities for C22 and C45
From:   Klaus Kudielka <klaus.kudielka@gmail.com>
To:     Andrew Lunn <andrew@lunn.ch>
Cc:     Michael Walle <michael@walle.cc>,
        Heiner Kallweit <hkallweit1@gmail.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>, Felix Fietkau <nbd@nbd.name>,
        John Crispin <john@phrozen.org>,
        Sean Wang <sean.wang@mediatek.com>,
        Mark Lee <Mark-MC.Lee@mediatek.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Bryan Whitehead <bryan.whitehead@microchip.com>,
        UNGLinuxDriver@microchip.com,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-aspeed@lists.ozlabs.org,
        Jesse Brandeburg <jesse.brandeburg@intel.com>
Date:   Sun, 12 Mar 2023 10:04:11 +0100
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On Sun, 2023-03-12 at 03:53 +0100, Andrew Lunn wrote:
> >=20
> > What you are proposing here would not show any improvement on the
> > Omnia, as only the 6 ports would be scanned - right?=20
>=20
> Correct. But their also should not of been any noticeable slow down,
> because there should not be any additional scanning when everything is
> described in DT. And the move of the MDIO bus registration from probe
> to setup should actually make it faster than before.
>=20

But then, why *do* I see such a big difference on the Omnia?

mdiobus_scan_bus_c45() takes:
~2.7 seconds without phy_mask patch
~0.2 seconds with phy_mask patch

(It's not a big deal, but somehow strange)

Regards, Klaus


PS: There was another open question: How long does the first
unsuccessful mv88e6xxx_probe() take, when calling
mv88e6xxx_mdios_register() from mv88e6xxx_setup()?

I would say "negligible":

[    0.194414] mv88e6085 f1072004.mdio-mii:10: *** mv88e6xxx_probe call ***
[    0.194739] mv88e6085 f1072004.mdio-mii:10: switch 0x1760 detected: Marv=
ell 88E6176, revision 1
[    0.208163] mv88e6085 f1072004.mdio-mii:10: *** mv88e6xxx_probe return -=
517 ***