From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sunset.davemloft.net (74-93-104-97-Washington.hfc.comcastbusiness.net [74.93.104.97]) by ozlabs.org (Postfix) with ESMTP id 26654B71BC for ; Fri, 19 Nov 2010 06:33:41 +1100 (EST) Date: Thu, 18 Nov 2010 11:34:05 -0800 (PST) Message-Id: <20101118.113405.116386129.davem@davemloft.net> To: mlcreech@gmail.com Subject: Re: Gianfar TCP checksumming broken in 2.6.35+ From: David Miller In-Reply-To: References: <20101118.090615.71123752.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Cc: linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Matthew L. Creech" Date: Thu, 18 Nov 2010 14:31:46 -0500 > On Thu, Nov 18, 2010 at 12:06 PM, David Miller = wrote: >> >> Can someone please follow up Matthew to get this bug resolved? =A0It= has >> been sitting around for a long time. >> >> I suspect the gianfar driver, for these chip revisions, will need to= >> do a software checksum when the offset matches the criteria mentione= d >> in the errata above. >> > = > I added a patch for this which fixes our affected systems; however, I= > don't know if this is a good way to perform checksum offloading, I > just kind of dug around until I found a function that seemed like it > worked. :) Patch against 2.6.36 is below for reference. It looks fine except I would limit the software checksum to the exact conditions listed in the errate. Otherwise this is going to hurt performance and cpu utilization quite a bit.