From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751994Ab2LTJRm (ORCPT ); Thu, 20 Dec 2012 04:17:42 -0500 Received: from cpsmtpb-ews03.kpnxchange.com ([213.75.39.6]:52023 "EHLO cpsmtpb-ews03.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274Ab2LTJRi (ORCPT ); Thu, 20 Dec 2012 04:17:38 -0500 Message-ID: <50D2D7BD.3030801@erwinrol.com> Date: Thu, 20 Dec 2012 10:17:49 +0100 From: Erwin Rol Organization: Erwin Rol Software Engineering User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Nicolas Ferre CC: linux-kernel@vger.kernel.org, Havard Skinnemoen , linux-arm-kernel , matteo.fortini@sadel.it, netdev Subject: Re: at91sam9260 MACB problem with IP fragmentation References: <50C08233.9030905@erwinrol.com> <50C09D2E.8050608@atmel.com> In-Reply-To: <50C09D2E.8050608@atmel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 20 Dec 2012 09:17:36.0105 (UTC) FILETIME=[D99B7D90:01CDDE92] X-RcptDomain: vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hallo Nicolas, On 6-12-2012 14:27, Nicolas Ferre wrote: > Erwin, > > On 12/06/2012 12:32 PM, Erwin Rol : >> Hello Nicolas, Havard, all, >> >> I have a very obscure problem with a at91sam9260 board (almost 1 to 1 >> copy of the Atmel EK). >> >> The MACB seems to stall when I use large (>2 * MTU) UDP datagrams. The >> test case is that a udp echo client (PC) sends datagrams with increasing >> length to the AT91 until the max length of the UDP datagram is reached. >> When there is no IP fragmentation everything is fine, but when the >> datagrams are starting to get fragmented the AT91 will not reply >> anymore. But as soon as some network traffic happens it goes on again, >> and non of the data is lost. >> I tried several kernels including the test version from Nicolas that he >> posted on LKML in October. They all show the same effect. > > [..] > > It seems that Matteo has the same behavior: check here: > http://www.spinics.net/lists/netdev/msg218951.html I tried Matteo's patch and it seems to work. But I don't know if the patch is really the right solution. I checked again with wireshark and it really seems the sending that stalls not the receiving. But as soon as a ethernet frame is received the sending "un-stalls". So maybe the patch just causes an MACB IRQ at certain moments that causes the sending to continue? > I am working on the macb driver right now, so I will try to reproduce > and track this issue on my side. Any luck reproducing it ? - Erwin