Re: [PATCH net-next v4 09/13] net: phylink: Use phy_caps_lookup for fixed-link configuration

[Russell King (Oracle)]

On Thu, Mar 06, 2025 at 11:12:20AM +0100, Maxime Chevallier wrote:
> On Thu, 6 Mar 2025 09:56:32 +0100
> Paolo Abeni <pabeni@xxxxxxxxxx> wrote:
> 
> > On 3/3/25 10:03 AM, Maxime Chevallier wrote:
> > > @@ -879,8 +880,10 @@ static int phylink_parse_fixedlink(struct phylink *pl,
> > >  	linkmode_copy(pl->link_config.advertising, pl->supported);
> > >  	phylink_validate(pl, pl->supported, &pl->link_config);
> > >  
> > > -	s = phy_lookup_setting(pl->link_config.speed, pl->link_config.duplex,
> > > -			       pl->supported, true);
> > > +	c = phy_caps_lookup(pl->link_config.speed, pl->link_config.duplex,
> > > +			    pl->supported, true);
> > > +	if (c)
> > > +		linkmode_and(match, pl->supported, c->linkmodes);  
> > 
> > How about using only the first bit from `c->linkmodes`, to avoid
> > behavior changes?
> 
> If what we want is to keep the exact same behaviour, then we need to
> go one step further and make sure we keep the same one as before, and
> it's not guaranteed that the first bit in c->linkmodes is this one.
> 
> We could however have a default supported mask for fixed-link in phylink
> that contains all the linkmodes we allow for fixed links, then filter
> with the lookup, something like :
> 
> 
> -       linkmode_fill(pl->supported);
> +       /* (in a dedicated helper) Linkmodes reported for fixed links below
> +        * 10G */
> +       linkmode_zero(pl->supported);
> +
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_5000baseT_Full_BIT, pl->supported);
> +       linkmode_set_bit(ETHTOOL_LINK_MODE_10000baseT_Full_BIT, pl->supported);

Good idea, but do we have some way to automatically generate the baseT
link modes?

-- 
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