From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Yang Subject: Re: [PATCH net] net/mlx4_en: correct the endianness of doorbell_qpn on big endian platform Date: Mon, 8 Dec 2014 22:42:37 +0800 Message-ID: <20141208144237.GB8382@richard> References: <1417315431-16761-1-git-send-email-weiyang@linux.vnet.ibm.com> <20141205.213112.1199355931404701216.davem@davemloft.net> <1417844801.15618.30.camel@edumazet-glaptop2.roam.corp.google.com> <063D6719AE5E284EB5DD2968C1650D6D1CA04A51@AcuExch.aculab.com> Reply-To: Wei Yang Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "'Eric Dumazet'" , David Miller , "weiyang@linux.vnet.ibm.com" , "netdev@vger.kernel.org" , "gideonn@mellanox.com" , "edumazet@google.com" , "amirv@mellanox.com" To: David Laight Return-path: Received: from e23smtp07.au.ibm.com ([202.81.31.140]:37673 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbaLHOmp (ORCPT ); Mon, 8 Dec 2014 09:42:45 -0500 Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 9 Dec 2014 00:42:43 +1000 Received: from d23relay07.au.ibm.com (d23relay07.au.ibm.com [9.190.26.37]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 6DB0C3578058 for ; Tue, 9 Dec 2014 01:42:40 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay07.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sB8EgdpB39715040 for ; Tue, 9 Dec 2014 01:42:40 +1100 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sB8Egc74027139 for ; Tue, 9 Dec 2014 01:42:39 +1100 Content-Disposition: inline In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CA04A51@AcuExch.aculab.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Dec 08, 2014 at 10:00:19AM +0000, David Laight wrote: >From: Eric Dumazet >> On Fri, 2014-12-05 at 21:31 -0800, David Miller wrote: >> >> > Guys, let's figure out what we are doing with this patch. >> > -- >> >> Oh well, patch is fine, please apply it, thanks ! > >I'm not to sure that the patch doesn't generate a software byteswap >followed by a byteswapping write on ppc - clearly not ideal. >It might even generate back to back software byteswaps. > >If the write to the doorbell register includes a byteswap on BE (ppc) >then there is no real value in keeping the value as BE. > >OTOH ppc ought to have ways of doing IO writes without the byteswap >(and byteswapping accesses to non-io memory for that matter). > >What happens on a BE system with BE peripherals is another matter. David Thanks for your comment. How about use __raw_writel() to replace the iowrite32()? Looks this is better, if so, I will make up another version for this. > > David > -- Richard Yang Help you, Help me