Re: [RFC net-next 0/4] ethtool: CMIS module diagnostic loopback support

[Maxime Chevallier]

Hi Björn,

On 22/02/2026 20:58, Björn Töpel wrote:

> # # Simple MAC loopback:
> # ethtool --set-loopback eth0 mac (Defaults: lanes=all, dir=near)
> # # Specific SerDes (PMA) lane:
> # ethtool --set-loopback eth0 pma:lane0
> # # Complex multi-layer (PMA Near + PMD Far):
> # ethtool --set-loopback eth0 pma:0x1:near pmd:all:far
> # # Disable all loopbacks:
> ethtool --set-loopback eth0 off
> 
> Thoughts? Is this somewhat close to what you had in mind, Andrew?
> 
> I'm far from an expert on the details here, so the folks with more
> knowledge, please chime in!

I'm very sorry not to have looked into this yet, I'm having some family
events to handle right-now but I hope to be back next monday to take a
close look at this :)

Thanks for this work,

Maxime