Limited support of NAND features in MTD.

Alexey Korolev akorolev at infradead.org
Wed Dec 19 06:55:33 EST 2007


Hi
> 
> On Wed, 2007-12-19 at 10:49 +0000, Alexey Korolev wrote:
> > Hmm I did not heard about this. Could you please give more details on
> > how partial page read can suffer from lack of ECC?
> 
> If your ECC covers the whole page, you have to read the whole page in
> order to check ECC.
> 
> Of course, if you do ECC in sub-pages in the first place, you can read
> only a single ECC block. But you still can't just read arbitrary byte
> ranges.
> 
It seems misunderstaning takes place here. Under partial/subpage page read we understand reading block of data covered by ECC. It means if we request to read 40bytes - we will read data equal to ECC step (it could be 256 bytes or 512bytes -depending on boundary conditions, but not 2048/4096 bytes in case of whole page read). If we have MLC NAND with whole page covered by ECC partial/subpage page read will be equivalent to page read. 

P/S
If partial page read name cause misunderstanding will subpage read name be obvious enough?

Thanks,
Alexey



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