[Yaffs] Bad block management

[Aras Vaichas]

Jacob Dall wrote:
>>>I've a few questions regarding why yaffs' bad block management is designed
>>>the way it is.
>>>I've an issue with some of my devices - bad blocks is increased very
>>>rapidly. Beyond the fact that it's due to ECC read errors, I'm yet to
>>>discover the root of the problem.
>>
>>What do you mean by  rapidly? I assume it is far worse than either of these!
> 
> Yes, it's far worse. Imagine having a system that, when looked at, has 2 bad blocks. One hour later it has over 500!!
> And this in a system that every 15 second writes approc. 10KB of data

I had exactly this same problem and it was fixed by using the proper ECC 
settings but I am using the kernel module version of YAFFS as opposed to the 
"direct" version.


>>>>I'm not blaming yaffs - I'm sure the problem is to be found else where, but
>>>I'm thinking really hard of making those changes to yaffs, making me able
>>>to get back to the state when the NAND was first taken into use.

I "lost" several NAND chips during my development. I simply hacked the FLASH 
erase utilities to ignore the ignore markers and erase the bad blocks anyway 
until I got everything working and "rescued" the chips.

This might help you:

http://www.aleph1.co.uk/pipermail/yaffs/2004q4/000854.html
http://www.aleph1.co.uk/pipermail/yaffs/2004q4/000868.html

regards,

Aras Vaichas