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Message-ID: <ZO8QbyKphyTmuv/g@localhost.localdomain>
Date: Wed, 30 Aug 2023 11:48:31 +0200
From: Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>
To: Lukasz Majewski <lukma@...x.de>
Cc: Eric Dumazet <edumazet@...gle.com>, Andrew Lunn <andrew@...n.ch>,
davem@...emloft.net, Woojung Huh <woojung.huh@...rochip.com>,
Vladimir Oltean <olteanv@...il.com>,
Oleksij Rempel <o.rempel@...gutronix.de>, Tristram.Ha@...rochip.com,
Florian Fainelli <f.fainelli@...il.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
UNGLinuxDriver@...rochip.com, Russell King <linux@...linux.org.uk>,
Heiner Kallweit <hkallweit1@...il.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] net: phy: Provide Module 4 KSZ9477 errata
(DS80000754C)
On Wed, Aug 30, 2023 at 11:21:19AM +0200, Lukasz Majewski wrote:
> The KSZ9477 errata points out (in 'Module 4') the link up/down problem
> when EEE (Energy Efficient Ethernet) is enabled in the device to which
> the KSZ9477 tries to auto negotiate.
>
> The suggested workaround is to clear advertisement of EEE for PHYs in
> this chip driver.
>
> Signed-off-by: Lukasz Majewski <lukma@...x.de>
Hi,
As the net is target you should add fixes tag which the commit that your
changes is fixing (workarounding :) )
> ---
> drivers/net/phy/micrel.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
> index 87b090ad2874..469dcd8a5711 100644
> --- a/drivers/net/phy/micrel.c
> +++ b/drivers/net/phy/micrel.c
> @@ -1418,6 +1418,35 @@ static int ksz9131_get_features(struct phy_device *phydev)
> return 0;
> }
>
> +static int ksz9477_get_features(struct phy_device *phydev)
> +{
> + __ETHTOOL_DECLARE_LINK_MODE_MASK(zero) = { 0, };
= { 0 };
> + int ret;
> +
> + ret = genphy_read_abilities(phydev);
> + if (ret)
> + return ret;
> +
> + /* KSZ9477 Errata DS80000754C
> + *
> + * Module 4: Energy Efficient Ethernet (EEE) feature select must be
> + * manually disabled
> + * The EEE feature is enabled by default, but it is not fully
> + * operational. It must be manually disabled through register
> + * controls. If not disabled, the PHY ports can auto-negotiate
> + * to enable EEE, and this feature can cause link drops when linked
> + * to another device supporting EEE.
> + *
> + * Although, the KSZ9477 MMD register
> + * (MMD_DEVICE_ID_EEE_ADV.MMD_EEE_ADV) advertise that EEE is
> + * operational one needs to manualy clear them to follow the chip
> + * errata.
> + */
> + linkmode_and(phydev->supported_eee, phydev->supported, zero);
> +
> + return 0;
> +}
> +
> #define KSZ8873MLL_GLOBAL_CONTROL_4 0x06
> #define KSZ8873MLL_GLOBAL_CONTROL_4_DUPLEX BIT(6)
> #define KSZ8873MLL_GLOBAL_CONTROL_4_SPEED BIT(4)
> @@ -4871,7 +4900,7 @@ static struct phy_driver ksphy_driver[] = {
> .handle_interrupt = kszphy_handle_interrupt,
> .suspend = genphy_suspend,
> .resume = genphy_resume,
> - .get_features = ksz9131_get_features,
> + .get_features = ksz9477_get_features,
> } };
>
> module_phy_driver(ksphy_driver);
> --
> 2.20.1
>
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