netdev - Re: [PATCH net-next 2/6] net: phylink: Allow more interfaces in SFP interface selection

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Message-ID: <aWgnHo01j38TF3lp@shell.armlinux.org.uk>
Date: Wed, 14 Jan 2026 23:30:38 +0000
From: "Russell King (Oracle)" <linux@...linux.org.uk>
To: Maxime Chevallier <maxime.chevallier@...tlin.com>
Cc: davem@...emloft.net, Andrew Lunn <andrew@...n.ch>,
	Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
	Jonas Jelonek <jelonek.jonas@...il.com>,
	Florian Fainelli <f.fainelli@...il.com>,
	Heiner Kallweit <hkallweit1@...il.com>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, thomas.petazzoni@...tlin.com,
	Simon Horman <horms@...nel.org>,
	Romain Gantois <romain.gantois@...tlin.com>,
	Marek Behún <kabel@...nel.org>,
	bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH net-next 2/6] net: phylink: Allow more interfaces in SFP
 interface selection

On Wed, Jan 14, 2026 at 11:57:24PM +0100, Maxime Chevallier wrote:
> When phylink handles an SFP module that contains a PHY, it selects a
> phy_interface to use to communicate with it. This selection ensures that
> the highest speed gets achieved, based on the linkmodes we want to
> support in the module.
> 
> This approach doesn't take into account the supported interfaces
> reported by the module

This is intentional by design, because the capabilities of the PHY
override in this case. Unfortunately, as I've said previously, the
rush to throw in a regurgitated version of my obsoleted
"host_interfaces" rather messed up my replacement patch set which
had the PHY driver advertising the interface capabilities of the
PHY, which were then going to be used to make the PHY interface
selection when attaching the PHY.

I've still got the code, but I can't now push it into mainline
because, with the obsolete host_interfaces stuff merged, we will end
up with two competing solutions.

In any case, I really would appreciate people looking through
http://git.armlinux.org.uk/cgit/linux-arm.git/log/?h=net-queue

before doing development on SFP and phylink to see whether I've
already something that solves their issue. Quite simply, I don't have
the time to push every patch out that I have, especially as I'm up to
my eyeballs with the crappy stmmac driver now, but also because I
have work items from Oracle that reduce the time I can work on
mainline. BTW, the "age" stated in cgit is based on the commit time
(which gets reset when rebased) not the initial merge time. You will
see that the "supported_interfaces" stuff dates from 2019, not 2025.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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