u32 slave_speed;
        int res;
 
-       slave->speed = -1;
-       slave->duplex = -1;
+       slave->speed = SPEED_UNKNOWN;
+       slave->duplex = DUPLEX_UNKNOWN;
 
        res = __ethtool_get_settings(slave_dev, &ecmd);
        if (res < 0)
 
        seq_printf(seq, "\nSlave Interface: %s\n", slave->dev->name);
        seq_printf(seq, "MII Status: %s\n",
                   (slave->link == BOND_LINK_UP) ?  "up" : "down");
-       if (slave->speed == -1)
+       if (slave->speed == SPEED_UNKNOWN)
                seq_printf(seq, "Speed: %s\n", "Unknown");
        else
                seq_printf(seq, "Speed: %d Mbps\n", slave->speed);
 
-       if (slave->duplex == -1)
+       if (slave->duplex == DUPLEX_UNKNOWN)
                seq_printf(seq, "Duplex: %s\n", "Unknown");
        else
                seq_printf(seq, "Duplex: %s\n", slave->duplex ? "full" : "half");
 
 #define SPEED_1000             1000
 #define SPEED_2500             2500
 #define SPEED_10000            10000
+#define SPEED_UNKNOWN          -1
 
 /* Duplex, half or full. */
 #define DUPLEX_HALF            0x00
 #define DUPLEX_FULL            0x01
+#define DUPLEX_UNKNOWN         0xff
 
 /* Which connector port. */
 #define PORT_TP                        0x00