Re: assert in phylink.c with lan7801 and dp83tc811 since kernel 6.18

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

On 06/05/2026 14:39, Andrew Lunn wrote:
>> So for me it somewhere happens in phylink_validate_mac_and_pcs()
> 
> I was expecting to see more debug output, but reading the code, i was
> also thinking we need to look at phylink_validate_mac_and_pcs().
> 
> You are going in the correct direction putting lots of printk() in the
> code. We need to find where it returns EINVAL:

[...]

> 
> In the end, we are probably going to find that what the MAC says its
> capabilities are don't match what the PCS says it can do.
> 
> Thinking about that, it says phy mode RGMII. You generally don't use a
> PCS with RGMII, so that is suspicious.
> 

Another thing to consider is that in this case, we're attaching to a
dp83tc811, so a 100BaseT1 PHY. Does the PHY driver correctly populates
the supported features ?

Could be that we're getting an empty-ish phydev->supported after reading
the abilities, as this is not a typical BaseT PHY

Maxime