diff --git a/devices/e100-2.6.37-ethercat.c b/devices/e100-2.6.37-ethercat.c
index 5a3098da..11b96fd3 100644
--- a/devices/e100-2.6.37-ethercat.c
+++ b/devices/e100-2.6.37-ethercat.c
@@ -2713,7 +2713,7 @@ static void e100_diag_test(struct net_device *netdev,
 {
 	struct ethtool_cmd cmd;
 	struct nic *nic = netdev_priv(netdev);
-	int i, err;
+	int i, err __attribute__ ((unused));
 
 	memset(data, 0, E100_TEST_LEN * sizeof(u64));
 	data[0] = !mii_link_ok(&nic->mii);