Re: [PATCH] sata_mv: Fix broken Marvell 7042 support.

[Jeff Garzik <jgarzik@pobox.com>]

Mark Lord wrote:
> Jeff Garzik wrote:
>> Mark Lord wrote:
>>> To do so, requires that we perhaps do a similar capacity truncation
>>> in sata_mv, but only if we see a metadata block at the expected location
>>> (because a "Legacy" mode drive will use the *real* capacity,
>>> placing the metadata in the 9th sector instead.
>>
>> Definitely _not_.  This is a core Linux maxim:  export what the 
>> hardware exports, no more no less.  We drive the "bare metal."
>>
>> OTOH it is quite reasonable to explore auto-loading DM on top of the 
>> bare drive, and populating a DM table, if you see that particular BIOS 
>> signature or [insert other detection method].
> ..
> 
> We must remember that *data integrity* trumps all other principles here.
> 
> If we don't strongly discourage/prevent the user from installing Linux
> or storing data in the corruptible region, they *will lose data*,
> and blame us.
> 
> These are bootable cards, so people will install distro's from scratch
> directly to them, or to RAIDs configured onto them by the distro.
> 
> So whatever we do has to be something *safe* for those situations.

Then auto-load a device map that gets it right.

The problem is not at the chip or device level, and this is the same 
problem as any number of other cards with softRAID on it.  Not a new 
problem, not a new solution...

	Jeff