@@ -904,9 +904,36 @@ static int ax88179_get_link_ksettings(struct net_device *net,
 				      struct ethtool_link_ksettings *cmd)
 {
 	struct usbnet *dev = netdev_priv(net);
+	struct ax88179_data *data;
+	int v;
+
+	data = dev->driver_priv;
 
 	mii_ethtool_get_link_ksettings(&dev->mii, cmd);
 
+	if (data->chip_version >= AX_VERSION_AX88279) {
+		linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+				 cmd->link_modes.supported);
+
+		v = ax88179_mdio_read(dev->net, dev->mii.phy_id, MII_ADVERTISE);
+		if (v >= 0 && v & AX_ADVERTISE_2500)
+			linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+					 cmd->link_modes.advertising);
+
+		v = ax_read_mmd(dev, MDIO_MMD_AN, MDIO_AN_10GBT_STAT);
+		if (data->speed == ETHER_LINK_2500) {
+			cmd->base.speed = SPEED_2500;
+			/* MDIO_AN_10GBT_STAT_LP2_5G is broken, but we can deduce that
+			 * the link-partner advertised 2500M if remotely AN succceded
+			 * for link speed > 1000M and we locally have a link speed of
+			 * 2500M
+			 */
+			if (v >= 0 && v & MDIO_AN_10GBT_STAT_REMOK)
+				linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+						 cmd->link_modes.lp_advertising);
+		}
+	}
+
 	return 0;
 }
 

@@ -914,6 +941,31 @@ static int ax88179_set_link_ksettings(struct net_device *net,
 				      const struct ethtool_link_ksettings *cmd)
 {
 	struct usbnet *dev = netdev_priv(net);
+	struct ax88179_data *data;
+	int v;
+
+	data = dev->driver_priv;
+
+	/* mii_ethtool_set_link_ksettings handles unknown bits in MII_ADVERTISE
+	 * transparently, so for the 2.5GBit link speed of the AX_VERSION_AX88279
+	 * we just set up AX_ADVERTISE_2500 before calling mii_ethtool_set_link_ksettings
+	 * at least for speeds < 2500
+	 */
+	if (data->chip_version == AX_VERSION_AX88279) {
+		v = ax88179_mdio_read(net, dev->mii.phy_id, MII_ADVERTISE);
+		if (v < 0)
+			return v;
+
+		if (linkmode_test_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+				      cmd->link_modes.advertising))
+			v |= AX_ADVERTISE_2500;
+		else
+			v &= ~AX_ADVERTISE_2500;
+		ax88179_mdio_write(net, dev->mii.phy_id, MII_ADVERTISE, v);
+		if (cmd->base.speed == SPEED_2500)
+			return mii_nway_restart(&dev->mii);
+	}
+
 	return mii_ethtool_set_link_ksettings(&dev->mii, cmd);
 }