diff options
| author | Ondrej Zary <linux@rainbow-software.org> | 2012-10-11 22:51:41 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-10-12 13:56:52 -0400 |
| commit | dabdaf0caa3af520dbc1df87b2fb4e77224037bd (patch) | |
| tree | 27de4c1b7c097ab07193e4ba29c6a11a6a08b53c | |
| parent | 93ac0ef016a1b223d23fbb5e0397cab75a8f7d34 (diff) | |
| download | lwn-dabdaf0caa3af520dbc1df87b2fb4e77224037bd.tar.gz lwn-dabdaf0caa3af520dbc1df87b2fb4e77224037bd.zip | |
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>
| -rw-r--r-- | drivers/net/usb/mcs7830.c | 30 |
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 = { |