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<bart.hartgers@xxxxxxxxx>
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. :-)
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