Re: [PATCH 1/2] dt-bindings: net: motorcomm: Add chip mode cfg

[Frank.Sae]

On 7/27/24 04:07, Andrew Lunn wrote:
> On Sat, Jul 27, 2024 at 11:25:25AM +0200, Krzysztof Kozlowski wrote:
> > On 27/07/2024 11:20, Frank.Sae wrote:
> > >   The motorcomm phy (yt8821) supports the ability to
> > >   config the chip mode of serdes.
> > >   The yt8821 serdes could be set to AUTO_BX2500_SGMII or
> > >   FORCE_BX2500.
> > >   In AUTO_BX2500_SGMII mode, SerDes
> > >   speed is determined by UTP, if UTP link up
> > >   at 2.5GBASE-T, SerDes will work as
> > >   2500BASE-X, if UTP link up at
> > >   1000BASE-T/100BASE-Tx/10BASE-T, SerDes will work
> > >   as SGMII.
> > >   In FORCE_BX2500, SerDes always works
> > >   as 2500BASE-X.
> When the SERDES is forced to 2500BaseX, does it perform rate
> adaptation? e.g. does it insert pause frames to slow down the MAC?
>
> Maybe look at air_en8811h.c.
>
>        Andrew

Yes, when the serdes is forced to 2500base-x, it inserts pause frames to
perform rate adaptation to slow down the MAC.