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authorOndrej Zary <linux@rainbow-software.org>2012-10-12 02:51:41 +0400
committerDavid S. Miller <davem@davemloft.net>2012-10-12 21:56:52 +0400
commitdabdaf0caa3af520dbc1df87b2fb4e77224037bd (patch)
tree27de4c1b7c097ab07193e4ba29c6a11a6a08b53c /drivers/net
parent93ac0ef016a1b223d23fbb5e0397cab75a8f7d34 (diff)
downloadlinux-dabdaf0caa3af520dbc1df87b2fb4e77224037bd.tar.xz
mcs7830: Fix link state detection
The device had an undocumented "feature": it can provide a sequence of spurious link-down status data even if the link is up all the time. A sequence of 10 was seen so update the link state only after the device reports the same link state 20 times. Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Reported-by: Michael Leun <lkml20120218@newton.leun.net> Tested-by: Michael Leun <lkml20120218@newton.leun.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/usb/mcs7830.c30
1 files changed, 21 insertions, 9 deletions
diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c
index 03c2d8d653df..cc7e72010ac3 100644
--- a/drivers/net/usb/mcs7830.c
+++ b/drivers/net/usb/mcs7830.c
@@ -117,6 +117,7 @@ enum {
struct mcs7830_data {
u8 multi_filter[8];
u8 config;
+ u8 link_counter;
};
static const char driver_name[] = "MOSCHIP usb-ethernet driver";
@@ -632,20 +633,31 @@ static int mcs7830_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
static void mcs7830_status(struct usbnet *dev, struct urb *urb)
{
u8 *buf = urb->transfer_buffer;
- bool link;
+ bool link, link_changed;
+ struct mcs7830_data *data = mcs7830_get_data(dev);
if (urb->actual_length < 16)
return;
link = !(buf[1] & 0x20);
- if (netif_carrier_ok(dev->net) != link) {
- if (link) {
- netif_carrier_on(dev->net);
- usbnet_defer_kevent(dev, EVENT_LINK_RESET);
- } else
- netif_carrier_off(dev->net);
- netdev_dbg(dev->net, "Link Status is: %d\n", link);
- }
+ link_changed = netif_carrier_ok(dev->net) != link;
+ if (link_changed) {
+ data->link_counter++;
+ /*
+ track link state 20 times to guard against erroneous
+ link state changes reported sometimes by the chip
+ */
+ if (data->link_counter > 20) {
+ data->link_counter = 0;
+ if (link) {
+ netif_carrier_on(dev->net);
+ usbnet_defer_kevent(dev, EVENT_LINK_RESET);
+ } else
+ netif_carrier_off(dev->net);
+ netdev_dbg(dev->net, "Link Status is: %d\n", link);
+ }
+ } else
+ data->link_counter = 0;
}
static const struct driver_info moschip_info = {