[Yaffs] Re: Writing a single file marks entire device as bad

Martin Egholm Nielsen martin at egholm-nielsen.dk
Fri Jul 22 09:00:47 BST 2005


>>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?
2) If I do the above, is there any difference in using the "-e" option 
on "mkyaffs" when formatting the device (mkyaffs -e /dev/mtd0) - or is 
this option only used when writing an image?

BR,
  Martin




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