Commit dabdaf0c authored by Ondrej Zary's avatar Ondrej Zary Committed by David S. Miller
Browse files

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: default avatarOndrej Zary <linux@rainbow-software.org>
Reported-by: default avatarMichael Leun <lkml20120218@newton.leun.net>
Tested-by: default avatarMichael Leun <lkml20120218@newton.leun.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 93ac0ef0

drivers/net/usb/mcs7830.c

+21 −9
Original line number Original line Diff line number Diff line
@@ -117,6 +117,7 @@ enum { 
struct mcs7830_data {

struct mcs7830_data {

	u8 multi_filter[8];

	u8 multi_filter[8];

	u8 config;

	u8 config;

	u8 link_counter;

};

};





static const char driver_name[] = "MOSCHIP usb-ethernet driver";

static const char driver_name[] = "MOSCHIP usb-ethernet driver";
@@ -632,13 +633,22 @@ static int mcs7830_rx_fixup(struct usbnet *dev, struct sk_buff *skb) 
static void mcs7830_status(struct usbnet *dev, struct urb *urb)

static void mcs7830_status(struct usbnet *dev, struct urb *urb)

{

{

	u8 *buf = urb->transfer_buffer;

	u8 *buf = urb->transfer_buffer;

	bool link;

	bool link, link_changed;

	struct mcs7830_data *data = mcs7830_get_data(dev);





	if (urb->actual_length < 16)

	if (urb->actual_length < 16)

		return;

		return;





	link = !(buf[1] & 0x20);

	link = !(buf[1] & 0x20);

	if (netif_carrier_ok(dev->net) != 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) {

			if (link) {

				netif_carrier_on(dev->net);

				netif_carrier_on(dev->net);

				usbnet_defer_kevent(dev, EVENT_LINK_RESET);

				usbnet_defer_kevent(dev, EVENT_LINK_RESET);
@@ -646,6 +656,8 @@ static void mcs7830_status(struct usbnet *dev, struct urb *urb) 
				netif_carrier_off(dev->net);

				netif_carrier_off(dev->net);

			netdev_dbg(dev->net, "Link Status is: %d\n", link);

			netdev_dbg(dev->net, "Link Status is: %d\n", link);

		}

		}

	} else

		data->link_counter = 0;

}

}





static const struct driver_info moschip_info = {

static const struct driver_info moschip_info = {

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