path: root/drivers
diff options
authorBjørn Mork <bjorn@mork.no>2013-04-18 12:57:11 +0000
committerDavid S. Miller <davem@davemloft.net>2013-04-19 17:51:17 -0400
commitcc6ba5fdaabea7a7b28de3ba1e0fe54d92232fe5 (patch)
treec9a0a487312539688bcac21db127bcbbef842764 /drivers
parent6483bdc9d76fb98174797516a19d289eb837909e (diff)
net: qmi_wwan: prevent duplicate mac address on link (firmware bug workaround)
We normally trust and use the CDC functional descriptors provided by a number of devices. But some of these will erroneously list the address reserved for the device end of the link. Attempting to use this on both the device and host side will naturally not work. Work around this bug by ignoring the functional descriptor and assign a random address instead in this case. Signed-off-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index cff0bbdd9f5..2a3579f6791 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -53,6 +53,9 @@ struct qmi_wwan_state {
struct usb_interface *data;
+/* default ethernet address used by the modem */
+static const u8 default_modem_addr[ETH_ALEN] = {0x02, 0x50, 0xf3};
/* Make up an ethernet header if the packet doesn't have one.
* A firmware bug common among several devices cause them to send raw
@@ -317,6 +320,12 @@ next_desc:
usb_driver_release_interface(driver, info->data);
+ /* Never use the same address on both ends of the link, even
+ * if the buggy firmware told us to.
+ */
+ if (!compare_ether_addr(dev->net->dev_addr, default_modem_addr))
+ eth_hw_addr_random(dev->net);
/* make MAC addr easily distinguishable from an IP header */
if (possibly_iphdr(dev->net->dev_addr)) {
dev->net->dev_addr[0] |= 0x02; /* set local assignment bit */