/* With the exclusion of 5325/5365, MII, Reverse MII and 802.3z, we
         * support Gigabit, including Half duplex.
+        *
+        * FIXME: this is weird - 802.3z is always Gigabit, but we exclude
+        * it here. Why? This makes no sense.
         */
-       if (state->interface != PHY_INTERFACE_MODE_MII &&
-           state->interface != PHY_INTERFACE_MODE_REVMII &&
-           !phy_interface_mode_is_8023z(state->interface) &&
-           !(is5325(dev) || is5365(dev))) {
+       if (!(state->interface == PHY_INTERFACE_MODE_MII ||
+             state->interface == PHY_INTERFACE_MODE_REVMII ||
+             phy_interface_mode_is_8023z(state->interface) ||
+             is5325(dev) || is5365(dev))) {
                phylink_set(mask, 1000baseT_Full);
                phylink_set(mask, 1000baseT_Half);
        }