Re: [Yaffs] failed erases causing block retirement

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Author: Benjamin Gamsa
Date:  
To: Charles Manning
CC: yaffs
Subject: Re: [Yaffs] failed erases causing block retirement
Charles Manning wrote:
> On Friday 29 May 2009 10:23:35 Ben Gamsa wrote:
>> Charles Manning wrote:
>>> It is safe to retry erases from a yaffs perspective, but if blocks are
>>> really failing erases (ie. not just a driver issue) I would be a bit
>>> concerned as to their health and would not want to reuse those blocks.
>> Right, that was my concern too. I guess what I wasn't sure of is
>> whether an erase failure is almost always (barring driver issues) an
>> indication of a bad block, or whether, like writes, it can be a
>> temporary glitch for which retries make sense. Since in my case it
>> turned out to be a driver issue, I still don't know the answer to this
>> question, but it is now less pressing.
>
> It very much depends on flash technology, but if you're getting write and
> erase errors I'd say you're typically playing with fire to keep using them.
>


Since yaffs retries on writes, I presume in the case of writes there is
good reason to believe that a block that fails to write once but
succeeds a second time is safe to keep using.

    ben