From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH 5/6] ide: remove broken disk byte-swapping support Date: Tue, 04 Dec 2007 15:44:40 +0300 Message-ID: <47554BB8.5070803@ru.mvista.com> References: <200712032253.26766.bzolnier@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from homer.mvista.com ([63.81.120.155]:49852 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753357AbXLDMoW (ORCPT ); Tue, 4 Dec 2007 07:44:22 -0500 In-Reply-To: <200712032253.26766.bzolnier@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Bartlomiej Zolnierkiewicz Cc: linux-ide@vger.kernel.org Bartlomiej Zolnierkiewicz wrote: > Remove broken disk byte-swapping support: > - it can cause a data corruption on SMP (or if using PREEMPT on UP) > - all data coming from disk are byte-swapped by taskfile_*_data() which > results in incorrect identify data being reported by /proc/ide/ and IOCTLs > - "hdx=bswap/byteswap" kernel parameter has been broken on m68k host drivers > (including Atari Q40 one) since 2.5.x days (because of 'hwif' zero-ing) > - byte-swapping is limited to PIO transfers (for working with TiVo disks on > x86 machines using user-space solutions or dm-byteswap should result in > much better performance because DMA can be used) > For previous discussions please see: > http://www.ussg.iu.edu/hypermail/linux/kernel/0201.0/0768.html > http://lkml.org/lkml/2004/2/28/111 > [ I have dm-byteswap device mapper target if somebody is interested > (patch is for 2.6.4 though but I'll dust it off if needed). ] > Signed-off-by: Bartlomiej Zolnierkiewicz Acked-by: Sergei Shtylyov MBR, Sergei