Re: [PATCH net-next v16 4/7] net: stmmac: qcom-ethqos: update phy_mode to the resolved interface in mac_finish()

On Wed, Oct 14, 2026 at 02:36:43PM +0200, Bartosz Golaszewski wrote:

ethqos->phy_mode is read by serdes_powerup() and
qcom_ethqos_set_sgmii_loopback() to configure the SerDes and its
wrapper for the correct interface. It is set once at probe from the DT
phy-mode property and never updated.

phylink resolves the actual runtime interface and passes it to the
mac_finish() callback. On platforms that only ever operate at one speed
these two values are always the same, but when the interface changes
at runtime - for example switching between SGMII and 2500BASE-X - the
stored value becomes stale. The next serdes_powerup() call, on
a subsequent link cycle, then reinitializes the SerDes to the wrong mode.

Update ethqos->phy_mode from the interface argument in
ethqos_mac_finish_serdes() so that it always reflects the last
resolved interface.

With that, we now update the phy_mode to the runtime-resolved interface,
so any subsequent resume with a 1G SGMII link skips the loopback setup
and the DMA reset hangs. To remedy this, extend the guard to include
PHY_INTERFACE_MODE_SGMII.

Signed-off-by: Bartosz Golaszewski <redacted>
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I am not sure but should this have a Fixes: tag?

Reviewed-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>

	Ayaan