OneNAND: Check first or second pages for bad block information

Artem Bityutskiy dedekind at infradead.org
Mon Jan 22 04:13:05 EST 2007


Hi,

On Mon, 2007-01-22 at 07:33 +0000, Kyungmin Park wrote:
> Hi,
>
> I'm not sure we have to check 2nd page. Yes, Spec. says we will check 
1st and 2nd ones.
>
> It increase the boot time even though it's smaller one than others.
>
Actually, if one is very concerned about BB scanning time, he should use 
on-flash BBT instead of in-memory BBT.

> Let me think, when we check 2nd page case.
> In initial bad, no need to check 2nd page.
> In runtime bad, it is only happend when first page write failed. But 
during write it has non-0xFF value. so next time it will be detected as 
invalid.
>
My understanding is that the second page is used only when the first one 
could not be written to due to some reasons - dunno which reasons.

So I wonder, how sane is it to read 1st page's OOB, and if no read errors 
detected - avoid reading the second one.




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