[PATCH net-next v15 1/9] net: phy: aquantia: fix system interface type not updated in forced mode

[Jakub Kicinski]

On Wed, 23 Sep 2026 17:14:35 +0200 Bartosz Golaszewski wrote:
> aqr_gen1_read_status() decodes the MDIO_PHYXS_VEND_IF_STATUS register
> to determine which SerDes interface the PHY is currently using on its
> system side and stores the result in phydev->interface. phylink relies
> on this value to configure the MAC.
> 
> The autoneg == AUTONEG_DISABLE check is not correct:
> MDIO_PHYXS_VEND_IF_STATUS is set by the PHY firmware based on the
> negotiated link speed, not based on whether autoneg was used to reach
> it. When the link comes up at 1G in forced mode, the register correctly
> reads SGMII, but the early return prevents phydev->interface from being
> updated. It stays at whatever value it held before (typically 2500BASE-X
> from the initial autoneg run), so phylink configures the MAC for the
> wrong interface and the link cannot come up.
> 
> Remove the autoneg guard so that the system interface type is always
> decoded when the link is up.
> 
> Cc: stable at vger.kernel.org
> Fixes: 110a2432c520 ("net: phy: aquantia: add downshift support")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski at oss.qualcomm.com>

Sounds like a real regression, is it? Should we ship it to Linus
tomorrow so that it makes 7.3? stable + next does not compute for me