Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757626Ab2JLIwf (ORCPT ); Fri, 12 Oct 2012 04:52:35 -0400 Received: from mail-1-out2.atlantis.sk ([80.94.52.71]:53023 "EHLO mail.atlantis.sk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751238Ab2JLIwd (ORCPT ); Fri, 12 Oct 2012 04:52:33 -0400 To: "Andreas Mohr" Subject: [PATCH v2] mcs7830: Fix link state detection Cc: "Greg KH" , davem@davemloft.net, Michael Leun , netdev@vger.kernel.org, Michael Leun , linux-kernel@vger.kernel.org Content-Disposition: inline From: Ondrej Zary Date: Fri, 12 Oct 2012 10:51:41 +0200 MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201210121051.42359.linux@rainbow-software.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2324 Lines: 73 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 Reported-by: Michael Leun Tested-by: Michael Leun --- 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 03c2d8d..cc7e720 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 = { -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/