From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Hancock Subject: Re: [patch 2/2] sata_via: Delay on vt6420 when starting ATAPI DMA write Date: Tue, 19 Jan 2010 22:53:55 -0600 Message-ID: <4B568C63.4050506@gmail.com> References: <20100116235653.898098245@gmail.com> <20100116235851.884756038@gmail.com> <4B5678E2.2050709@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B5678E2.2050709@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Tejun Heo Cc: Bart Hartgers , linux-kernel@vger.kernel.org, Jeff Garzik , 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 List-Id: linux-ide@vger.kernel.org On 01/19/2010 09:30 PM, Tejun Heo wrote: > 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 > > 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. Another tiny nitpick about the patch, the unlikely() around the DMA_TO_DEVICE check probably shouldn't be there - unlikely() is for things that will always be either highly unlikely or a slow path, neither of which really apply. > > 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. :-) >