Martin Egholm Nielsen wrote:
>>> Now, new strange things are happening!
>>> I enabled "CONFIG_MTD_NAND_VERIFY_WRITE=y" in the kernel, and 
>>> suddenly it begun working!!
>>
>> Odd but gratifying.
> 
> Yes...
> 
>>> However, I get these kernel messages (alot) whenever I try to 
>>> read/write anything:
>>>
>>> === 8< 8< 8< ===
>>>    Writing data without ECC to NAND-FLASH is not recommended
>>>    Writing data without ECC to NAND-FLASH is not recommended
>>>    Writing data without ECC to NAND-FLASH is not recommended
>>>    Writing data without ECC to NAND-FLASH is not recommended
>>>    Reading data from NAND FLASH without ECC is not recommended
>>>
>>> I guess these must be from YAFFS...
>>
>> No, that is normal. If MTD is asked not to do its own ECC it whinges 
>> like mad. Comment it out.
> 
> Ok...
> 
>>> Is there really no ECC running now? I thought that config-option for 
>>> MTD did the job?
>>
>> You should only do this if yaffs is doing the ECC instead.
> 
> 
> So, this is how I have the configuration in order to get it to work:
> 
> YAFFS_USE_NANDECC=n
> CONFIG_MTD_NAND_VERIFY_WRITE=y
> 
> My questions now are then:
> 1) Is there any ECC enabled now?

I think it's not:
   - yaffs' ECC is disabled (YAFFS_USE_NANDECC=n)
   - from my understanding, the MTD ECC depend of your MTD NAND chip (the field eccmode of nand_chip,
     this value is set to NAND_ECC_NONE, NAND_ECC_SOFT, NAND_ECC_HW6_512, ...)
     You can only receive the message "Writing data without ECC to NAND-FLASH is not recommended"
     if eccmode is set to NAND_ECC_NONE.

What type of nand chip you use?
Have tried the options  CONFIG_MTD_NAND_VERIFY_WRITE=y && YAFFS_USE_NANDECC=y ?


Luc