From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Subject: Re: [PATCH 2/5] netdev: bfin_mac: fix malformed UDP packet transmission when polling with KGDB Date: Fri, 29 May 2009 06:46:46 -0400 Message-ID: <8bd0f97a0905290346v542e83cdg321241f0b4d95d9e@mail.gmail.com> References: <1243404615-25879-1-git-send-email-vapier@gentoo.org> <1243404615-25879-3-git-send-email-vapier@gentoo.org> <20090529.020405.170805407.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, uclinux-dist-devel@blackfin.uclinux.org, sonic.zhang@analog.com, cooloney@kernel.org To: David Miller Return-path: Received: from mail-gx0-f166.google.com ([209.85.217.166]:33097 "EHLO mail-gx0-f166.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752664AbZE2Kqp (ORCPT ); Fri, 29 May 2009 06:46:45 -0400 Received: by gxk10 with SMTP id 10so10235145gxk.13 for ; Fri, 29 May 2009 03:46:47 -0700 (PDT) In-Reply-To: <20090529.020405.170805407.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, May 29, 2009 at 05:04, David Miller wrote: > From: Mike Frysinger >> From: Sonic Zhang >> >> Make sure data is really written into the registers before enabling DMA. >> Otherwise, the EMAC DMA controller may transfer out a malformed packet. >> This patch may also fix netperf bugs or scp bugs. >> >> Signed-off-by: Sonic Zhang >> Signed-off-by: Mike Frysinger >> Signed-off-by: Bryan Wu > > Instead of using this incredibly non-portable blackfin specific SSYNC > thing that doesnt make sense -- this is a completely non-portable Blackfin specific driver. everything in it uses Blackfin macros to access Blackfin MMRs because this is a device that only exists on Blackfin chips. > why not read back a register from the device to ensure the > register writes hit the chip just like other drivers do? because that isnt how the Blackfin hardware works in general, and certainly not how the DMA hardware works. > If that doesn't work, enhance your commit message to describe (in > detail) why SSYNC is the only way to make this work properly. this is how it always is for all Blackfin on-chip registers, and the hardware manual specifically dictates using SSYNC. -mike