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

[Boris Brezillon]

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?

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com