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Subject: RE: [PATCH 1/2] mtd: OneNAND: Add runtime badblock check feature
From: Artem Bityutskiy <dedekind1@gmail.com>
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Date: Mon, 14 Jun 2010 07:07:00 +0300
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On Mon, 2010-06-14 at 08:19 +0900, Kyungmin Park wrote:
> > Also, if you really want this, it should be rather lazy checking, where
> > you read OOB on demand, and then save this information to the in-ram
> > BBT, and when you get another ->block_isbad() for a block which was
> > previously checked, you do not read OOB for the second time.
> 
> It's based on BBT already. Now I set the BBT values as 0x2 and then
> check it at runtime and then mark it 0 for good, 3 for bad block.

I meant why you are optimizing the in-ram BBT instead of just keeping
and maintaining the BBT on the flash media?

> Right, it's same word lazy checking and runtime check.

I think you should rename it. "Runtime" is not descriptive, because even
without your patch the BBT is built "runtime". But "lazy" BBT creation
is quite descriptive.

> The original ideas are from UBI scan it read all blocks again at probe.
> I just scan almost block read once at ubi scan.

Right. So I asked why not to just have the BBT on flash?

Also, I doubt we need yet another config option and chip option - why
not to make lazy BBT just to be the default?

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)