dm9601: handle corrupt mac address

Some cheap devices ship with dangling EEPROM pins!
They always return invalid address ff:ff:ff:ff:ff:ff.

Inherit the auto-generated address in this case,
so that these products can work with zero configuration.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c
index edd244f..69a0436 100644 (file)
--- a/drivers/net/usb/dm9601.c
+++ b/drivers/net/usb/dm9601.c
@@ -414,6 +414,7 @@ static int dm9601_set_mac_address(struct net_device *net, void *p)
 static int dm9601_bind(struct usbnet *dev, struct usb_interface *intf)
 {
        int ret;
+       u8 mac[ETH_ALEN];
 
        ret = usbnet_get_endpoints(dev, intf);
        if (ret)
@@ -438,12 +439,18 @@ static int dm9601_bind(struct usbnet *dev, struct usb_interface *intf)
        udelay(20);
 
        /* read MAC */
-       if (dm_read(dev, DM_PHY_ADDR, ETH_ALEN, dev->net->dev_addr) < 0) {
+       if (dm_read(dev, DM_PHY_ADDR, ETH_ALEN, mac) < 0) {
                printk(KERN_ERR "Error reading MAC address\n");
                ret = -ENODEV;
                goto out;
        }
 
+       /*
+        * Overwrite the auto-generated address only with good ones.
+        */
+       if (is_valid_ether_addr(mac))
+               memcpy(dev->net->dev_addr, mac, ETH_ALEN);
+
        /* power up phy */
        dm_write_reg(dev, DM_GPR_CTRL, 1);
        dm_write_reg(dev, DM_GPR_DATA, 0);