Re: [PATCH RFC net-next 05/12] net: dsa: bcm_sf2: convert to phylink_generic_validate()

Andrew Lunn
2021-12-04T15:01:54Z

> The order of 1000baseKX/Full and 1000baseT/Full is such that we
> prefer 1000baseKX/Full over 1000baseT/Full, but 1000baseKX/Full is
> a lot rarer than 1000baseT/Full, and thus is much less likely to
> be preferred.
>
> This causes phylink problems - it means a fixed link specifying a
> speed of 1G and full duplex gets an ethtool linkmode of 1000baseKX/Full
> rather than 1000baseT/Full as would be expected - and since we offer
> userspace a software emulation of a conventional copper PHY, we want
> to offer copper modes in preference to anything else. However, we do
> still want to allow the rarer modes as well.

2.5G already places T before X, so it makes it more uniform with that.

For 10G, T comes last. Maybe we should also consider this case? Do we
see more 10G copper than fibre/backplane?

Andrew