From: Sergei Shtylyov <sshtylyov@ru.mvista.com>
To: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: [PATCH 5/6] ide: remove broken disk byte-swapping support
Date: Tue, 04 Dec 2007 15:44:40 +0300 [thread overview]
Message-ID: <47554BB8.5070803@ru.mvista.com> (raw)
In-Reply-To: <200712032253.26766.bzolnier@gmail.com>
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 <bzolnier@gmail.com>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
MBR, Sergei
prev parent reply other threads:[~2007-12-04 12:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-03 21:53 [PATCH 5/6] ide: remove broken disk byte-swapping support Bartlomiej Zolnierkiewicz
2007-12-04 12:44 ` Sergei Shtylyov [this message]
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