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Date: Wed, 20 Jan 2010 07:44:07 +0100
Message-ID: <7eb6a4d81001192244k19d28805p9cb4eaec7eed9366@mail.gmail.com>
Subject: Re: [patch 2/2] sata_via: Delay on vt6420 when starting ATAPI DMA 
	write
From: Bart Hartgers <bart.hartgers@gmail.com>
To: Tejun Heo <htejun@gmail.com>
Cc: linux-kernel@vger.kernel.org, Jeff Garzik <jgarzik@pobox.com>,
       linux-ide@vger.kernel.org, juergen.metzdorf@telelev-dsl.de,
       markpschool@hotmail.com, sporadic.crash@gmail.com, apopov@sirma.bg,
       david@coomber.co.za, jay4mail@gmail.com
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Hi,

2010/1/20 Tejun Heo <htejun@gmail.com>:
> Hello,
>
> On 01/17/2010 08:56 AM, Bart Hartgers wrote:
>> When writing a disc on certain lite-on dvd-writers (also rebadged as
>> optiarc/LG/...) connected to a vt6420, the ATAPI CDB ends up in the
>> datastream and on the disc, causing silent corruption.  Delaying
>> between sending the CDB and starting DMA seems to prevent this.
>>
>> I do not know if there are burners that do not suffer from this, but
>> the patch should be safe for those as well.
>>
>> There are many reports of this issue, but AFAICT no solution was
>> found before. For example:
>> http://lkml.indiana.edu/hypermail/linux/kernel/0802.3/0561.html
>>
>> Signed-off-by: Bart Hartgers <bart.hartgers@gmail.com>
>
> Ah... you found solution for this?  That's great.  This is one of the
> three problems that have been lingering for years - the other two
> being pata_ali ATAPI DMA problem and sata_sil data corruption problem.
> I'll be ecstatic if this fix works.  Just one thing, I don't think
> we'll need a warning message there.  It's useful during development
> but it doesn't really provide any useful information afterwards.
>

Yes, you're right. I'll drop the printk_once and send another patch
for inclusion. However, for testing I found it very useful to make
sure that I got the right module loaded. So I figured it could be
helpful for the interpretation of success/failure reports.

Assuming that this patch works for other people as well, what is
prefered: resending both patches or just to make a new #2/2 (the
vt6420 one)?

Groeten,
Bart

> Digging up the mailing list and cc'ing people who have reported this
> problem.  If you still have the affected systems, can you guys please
> test the patch in the following message and see whether it fixes the
> problem?
>
>  http://article.gmane.org/gmane.linux.kernel/939112/raw
>
> Thanks a lot.  :-)
>
> --
> tejun
>


-- 
Bart Hartgers - New e-mail: bart.hartgers@gmail.com
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