diff -r 5be97f6cc76a -r fe87d02a6790 devices/r8169-2.6.37-ethercat.c
--- a/devices/r8169-2.6.37-ethercat.c	Tue Jan 10 10:43:36 2012 +0100
+++ b/devices/r8169-2.6.37-ethercat.c	Tue Jan 10 10:43:56 2012 +0100
@@ -4956,6 +4956,9 @@
 	struct net_device *dev = pci_get_drvdata(pdev);
 	struct rtl8169_private *tp = netdev_priv(dev);
 
+	if (tp->ecdev)
+		return -EBUSY;
+
 	rtl8169_init_phy(dev, tp);
 
 	if (netif_running(dev))