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

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

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:
>> 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