Hi Russell,

On 15/01/2026 00:30, Russell King (Oracle) wrote:

On Wed, Jan 14, 2026 at 11:57:24PM +0100, Maxime Chevallier wrote:

quoted

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.

net-next being closed, I was going through my backlog and I was thinking
about giving this series another go after net-next re-opens, I'd like to
sync with you about the way forward.

In your tree there's :

net: phylink: use phy interface mode bitmaps for SFP PHYs	
net: phy: add supported_interfaces to Aquantia AQR113C
net: phy: add supported_interfaces to marvell10g PHYs
net: phy: add supported_interfaces to marvell PHYs
net: phy: add supported_interfaces to bcm84881
net: phy: add supported_interfaces to phylib

These would be pre-requisites for the 100FX-SGMII SFP support, as the
interface resolution currently doesn't elect SGMII for 100FX modules.

That would require some changes to the current host_interfaces API as
well, potentially replacing it altogether.

Is this something you can do, or can I get your permission to submit
these (ofc maybe with more stuff to deal with host_interfaces)

Thanks,

Maxime