[Yaffs] Bad block management

[Jacob Dall]

Hello Aras,

At 02:37 31-01-2005, you wrote:
>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 a bit curious; what settings did you change to achieve 'proper ECC 
settings'?



>>>>>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
>
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