From mboxrd@z Thu Jan 1 00:00:00 1970 From: Baruch Siach Subject: [PATCH] enc28j60: Fix sporadic packet loss Date: Tue, 2 Dec 2008 14:50:46 +0200 Message-ID: <20081202125046.GD24490@diamond.tkos.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Shachar Shemesh , netdev@vger.kernel.org To: Claudio Lanconelli Return-path: Received: from tango.tkos.co.il ([62.219.50.35]:48531 "EHLO tango.tkos.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754075AbYLBNPN (ORCPT ); Tue, 2 Dec 2008 08:15:13 -0500 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Packet data read from the RX buffer the when the RSV is at the end of the RX buffer does not warp around. This causes packet loss, as the actual data is never read. Fix this by calculating the right packet data location. Thanks to Shachar Shemesh for suggesting the fix. Signed-off-by: Baruch Siach --- --- drivers/net/enc28j60.c-git 2008-12-02 14:30:10.000000000 +0200 +++ drivers/net/enc28j60.c 2008-12-02 14:41:51.000000000 +0200 @@ -568,6 +568,17 @@ static u16 erxrdpt_workaround(u16 next_p return erxrdpt; } +/* + * Calculate wrap arround when reading beyond the end of the RX buffer + */ +static u16 rx_packet_start(u16 ptr) +{ + if (ptr + RSV_SIZE > RXEND_INIT) + return (ptr + RSV_SIZE) - (RXEND_INIT - RXSTART_INIT + 1); + else + return ptr; +} + static void nolock_rxfifo_init(struct enc28j60_net *priv, u16 start, u16 end) { u16 erxrdpt; @@ -938,8 +949,9 @@ static void enc28j60_hw_rx(struct net_de skb->dev = ndev; skb_reserve(skb, NET_IP_ALIGN); /* copy the packet from the receive buffer */ - enc28j60_mem_read(priv, priv->next_pk_ptr + sizeof(rsv), - len, skb_put(skb, len)); + enc28j60_mem_read(priv, + rx_packet_start(priv->next_pk_ptr), + len, skb_put(skb, len)); if (netif_msg_pktdata(priv)) dump_packet(__func__, skb->len, skb->data); skb->protocol = eth_type_trans(skb, ndev); -- ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -