From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from web53510.mail.yahoo.com (web53510.mail.yahoo.com [206.190.37.71]) by ozlabs.org (Postfix) with SMTP id 8383A2BEA0 for ; Wed, 17 Nov 2004 08:28:16 +1100 (EST) Message-ID: <20041116212814.592.qmail@web53510.mail.yahoo.com> Date: Tue, 16 Nov 2004 13:28:13 -0800 (PST) From: roger blofeld To: Dale Farnsworth In-Reply-To: <20041116201654.GA3088@xyzzy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linuxppc-embedded@ozlabs.org Subject: Re: Lite5200 FEC Driver on linux 2.6 broken? (again) List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --- Dale Farnsworth wrote: > On Tue, Nov 16, 2004 at 10:26:09AM -0800, roger blofeld wrote: > > Retransmissions from the lite5200 work OK now, but the occasional > ACK > > packet is sent from the lite5200 with a bad checksum causing > > retransmissions. Perhaps another patch would fix this problem too? > > I too have seen occasional errors, but I don't think it's a software > issue. > > -Dale > One more clue to what is happening: Whenever a packet is transmitted with a bad checksum, the tail end of the data is in error. For example, a packet of 0x442 bytes (0x42 header, 0x400 data) is corrupt from byte 0x360 on. Corruption always happens at a multiple of 0x10 from the start of the packet. If it is software, perhaps we don't wait long enough for DMA completion, or DMA signals completion too soon? Or maybe the buffer is re-used or stomped on? Seems like too large of a corruption to be due to cache. -roger __________________________________ Do you Yahoo!? The all-new My Yahoo! - Get yours free! http://my.yahoo.com