Re: [PATCH net-next v2 4/5] net: pcs: qcom-ipq9574: Add USXGMII interface mode support

[Lei Wei]

On 12/4/2024 11:38 PM, Russell King (Oracle) wrote:
> On Wed, Dec 04, 2024 at 10:43:56PM +0800, Lei Wei wrote:
> > +static int ipq_pcs_link_up_config_usxgmii(struct ipq_pcs *qpcs, int speed)
> > +{
> ...
> > +	/* USXGMII only support full duplex mode */
> > +	val |= XPCS_DUPLEX_FULL;
>
> Again... this restriction needs to be implemented in .pcs_validate() by
> knocking out the half-duplex link modes when using USXGMII mode.
>
> .pcs_validate() needs to be implemented whenever the PCS has
> restrictions beyond what is standard for the PHY interface mode.

Currently, it seems there is no phylink_validate() call in 
phylink_resolve(), to validate the resolved duplex/speed which is 
notified by phydev when the PHY is linked up. So I am thinking to add 
this duplex check in this link_up op, and return an appropriate error in 
case of half-duplex. (Kindly correct me if I am wrong).

> Thanks.