On Sat, 7 Dec 2013, NeilBrown wrote:

quoted

I think I can come up with a patch to work around this - should I do
that and submit it (and if so, where should I send it)? Or would it be
better to describe the issues I've found in more detail first?

A patch is often a good way to describe an issue in detail - though you 
should include plain-language text as well of course. Patches can be 
posted to this list.

Great, thanks - I'll see what I can come up with.

The only "DDF" I've come across which mdadm doesn't like is DDFv1.0 
which has all multi-byte values in the "other" order, and uses a 
different checksum algorithm.  As I cannot find a document describing 
DDFv1.0 I cannot calculate the checksum so I cannot update the metadata, 
so I cannot use DDFv1.0.

The metadata claims to be DDFv1.2, but the implementation appears to be 
buggy. One of the bugs is that the CRC is non-standard, but I've managed 
to figure out how it calculates it, so it should be possible to update the 
metadata OK. I'll include full details with the patch.

-P

If the "minor" variances you found don't prevent us from being able to 
update the metadata and still have it recognised by the card, then I'm 
certainly interested in a patch.

Thanks,
NeilBrown

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