diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
index 47b70b5e706f221c01f1c0ae3b1acafae6641165..9d19203ae4bd7dc17aca068f5eb88ff830e4e906 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c
@@ -632,6 +632,12 @@ static int ethqos_mac_finish_serdes(struct net_device *ndev, void *priv,
 	struct qcom_ethqos *ethqos = priv;
 	int ret = 0;
 
+	/* The interface mode is only known once phylink has resolved it and
+	 * may change at runtime, so keep it in sync for later
+	 * serdes_powerup()/serdes_powerdown() calls.
+	 */
+	ethqos->phy_mode = interface;
+
 	qcom_ethqos_set_sgmii_loopback(ethqos, false);
 
 	if (interface == PHY_INTERFACE_MODE_SGMII ||