Re: [PATCH net-next 0/2] net: pcs: xpcs: fix operating mode selection

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Oct 14, 2026 at 05:30:57PM -0500, Alex Elder wrote:
> The XPCS found on Toshiba TC9564 is unable to operate at 2500base-X
> and slower with a PHY connected using SGMII/2500base-X.  This XPCS
> supports 10Gbase-R, which is the default operating mode, and this
> causes mode selection to fail for slower interfaces (SGMII, 1000baseX,
> and 2500baseX).  Writing a reserved value to the MDIO_CTRL2 register
> avoids this failure.
> 
> Wangxun already addresses a similar scenario, but includes custom
> quirk handling.
> 
> This series implements handling for slower rates for an XPCS that
> supports 10Gbase-R.  The first patch rearranges code that performs
> soft reset so that it is done *before* the interface mode is
> switched.  The second adds code to xpcs_switch_interface_mode()
> to update the MDIO_CTRL2 register for interfaces that support
> 10Gbase-R so that the desired rate change works as intended.

You Cc: those reported by get_maintainers, but i think a few other
people should be involved, who have made changes in this area:

Coia Prant <coiaprant@gmail.com>
Choong Yong Liang <yong.liang.choong@linux.intel.com>
Vladimir Oltean <vladimir.oltean@nxp.com>
Jiawen Wu <jiawenwu@trustnetic.com>

       Andrew