From: "Russell King (Oracle)" <linux@armlinux•org.uk>
To: Andrew Lunn <andrew@lunn•ch>
Cc: Heiner Kallweit <hkallweit1@gmail•com>,
"David S. Miller" <davem@davemloft•net>,
netdev@vger•kernel.org, Marek Beh__n <kabel@kernel•org>,
Jakub Kicinski <kuba@kernel•org>
Subject: Re: [PATCH RFC net-next] net: phy: marvell10g: add downshift tunable support
Date: Tue, 20 Jul 2021 15:30:46 +0100 [thread overview]
Message-ID: <20210720143046.GU22278@shell.armlinux.org.uk> (raw)
In-Reply-To: <YPbdfBqjgHzM+6+Z@lunn.ch>
On Tue, Jul 20, 2021 at 04:28:12PM +0200, Andrew Lunn wrote:
> > +static int mv3310_set_downshift(struct phy_device *phydev, u8 ds)
> > +{
> > + struct mv3310_priv *priv = dev_get_drvdata(&phydev->mdio.dev);
> > + u16 val;
> > + int err;
> > +
> > + /* Fails to downshift with v0.3.5.0 and earlier */
> > + if (priv->firmware_ver < MV_VERSION(0,3,5,0))
> > + return -EOPNOTSUPP;
> > +
> > + if (ds == DOWNSHIFT_DEV_DISABLE)
> > + return phy_clear_bits_mmd(phydev, MDIO_MMD_PCS, MV_PCS_DSC1,
> > + MV_PCS_DSC1_ENABLE);
> > +
> > + /* FIXME: The default is disabled, so should we disable? */
> > + if (ds == DOWNSHIFT_DEV_DEFAULT_COUNT)
> > + ds = 2;
>
> Interesting question.
>
> It is a useful feature, so i would enable it by default.
>
> Is it possible to read the actual speed via some vendor register? The
> phy-core might then give a warning, but it is 50/50 since the link
> peer might perform the downshift.
We already do read the actual negotiated speed anbd other parameters
from the MV_PCS_CSSR1 register.
--
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next prev parent reply other threads:[~2021-07-20 14:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-20 13:38 [PATCH RFC net-next] net: phy: marvell10g: add downshift tunable support Russell King
2021-07-20 14:28 ` Andrew Lunn
2021-07-20 14:30 ` Russell King (Oracle) [this message]
2021-07-20 15:04 ` Marek Behún
2021-07-20 17:14 ` Russell King (Oracle)
2021-07-20 17:32 ` Marek Behún
2021-07-20 17:39 ` Russell King (Oracle)
2021-07-20 17:50 ` Marek Behún
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