Re: [PATCH] phy: aquantia: Configure SERDES mode by default

From: Vladimir Oltean
Date: Tue Nov 15 2022 - 17:37:41 EST


On Mon, Nov 14, 2022 at 04:07:39PM -0500, Sean Anderson wrote:
> When autonegotiation completes, the phy interface will be set based on
> the global config register for that speed. If the SERDES mode is set to
> something which the MAC does not support, then the link will not come
> up. The register reference says that the SERDES mode should default to
> XFI, but for some phys lower speeds default to XFI/2 (5G XFI). To ensure
> the link comes up correctly, configure the SERDES mode.
>
> We use the same configuration for all interfaces. We don't advertise
> any speeds faster than the interface mode, so they won't be selected.
> We default to pause-based rate adaptation, but enable USXGMII rate
> adaptation for USXGMII. I'm not sure if this is correct for
> SGMII; it might need USXGMII adaptation instead.
>
> This effectively disables switching interface mode depending on the
> speed, in favor of using rate adaptation. If this is not desired, we
> would need some kind of API to configure things.
>
> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
> ---

Was this patch tested and confirmed to do something sane on any platform
at all?