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From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	kernel@pengutronix.de, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org
Subject: Re: [PATCH net-next v2 1/1] net: phy: Clear link-specific data on link down
Date: Fri, 22 Aug 2025 10:19:24 +0100	[thread overview]
Message-ID: <aKg2HHIBAR8t2CQW@shell.armlinux.org.uk> (raw)
In-Reply-To: <20250822090947.2870441-1-o.rempel@pengutronix.de>

On Fri, Aug 22, 2025 at 11:09:47AM +0200, Oleksij Rempel wrote:
> When a network interface is brought down, the associated PHY is stopped.
> However, several link-specific parameters within the phy_device struct
> are not cleared. This leads to userspace tools like ethtool reporting
> stale information from the last active connection, which is misleading
> as the link is no longer active.

This is not a good idea. Consider the case where the PHY has been
configured with autoneg disabled, and phydev->speed etc specifies
the desired speed.

When the link goes down, all that state gets cleared, and we lose
the user's settings.

So no, I don't think this is appropriate.

I think it is appropriate to clear some of the state, but anything that
the user can configure (such as ->speed and ->duplex) must not be
cleared.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

  reply	other threads:[~2025-08-22  9:19 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-22  9:09 [PATCH net-next v2 1/1] net: phy: Clear link-specific data on link down Oleksij Rempel
2025-08-22  9:19 ` Russell King (Oracle) [this message]
2025-08-22  9:29   ` Oleksij Rempel
2025-08-22  9:42     ` Russell King (Oracle)

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