[PATCH 1/2] mtd: nand: use a lower value for badblockbits when working with MLC NAND

[Andrea Scian]

Il 09/03/2016 15:26, Boris Brezillon ha scritto:
> On Tue, 1 Mar 2016 14:47:21 +0000
> Bean Huo 霍斌斌 (beanhuo) <beanhuo at micron.com> wrote:
>
>> Hi, Andrea and Boris
>> This is a historical subject, and talked before.
>>  From our field issues, 8 bits of bad block mark for MLC NAND is not reasonable.
>> Because of bitflip on bad block mark, regard one good block as a bad block is common
>> Issue. Especially first time boot after reflow. The solution is modified this value to 4 for MLC
>> NAND by hand, and the factory BB mark is “0x00”.
>> I think, 4 bits for MLC NAND make sense.
>
>
> I'm tempted to say "let's start with this value and see what happens in
> real world". If we want to be a bit more conservative we could decide
> to chose 2, which should address most problems too (during my tests, I
> never seen such a huge concentration of bitflips in the same byte).
>
> Brian, Andrea, what do you think?
>

I'm currently using 4 on my custom kernel.
On all datasheet I've seen factory bad block marker is 0x00 and the same 
is (AFAIK) used by MTD to mark bad blocks.

Kind Regards,

-- 

Andrea SCIAN

DAVE Embedded Systems