Re: JFFS2 impact when don't have sub page access

["Aníbal Almeida Pinto" <anibal.pinto@efacec.com>]

Em 02-08-2013 12:52, Gupta, Pekon escreveu:
> Hi,
>
>>>
>>>> Also, the subject talks about JFFS2. There is no known affect of absence
>>>> of subpage support on JFFS2, right?
>>>>
>>> There should not be any problem in using either UBIFS or JFFS2.
>>
>> Please, clarify me with the last statement.
>>
>> There should be no problem using JFFS2 or UBIFS with the patch that you
>> mention applied or even without the patch ?
>>
>
> For UBIFS to work,
> (1) please check following options passed for mkfs.ubifs
> - with this patch
> mkfs.ubifs -s 512  -m 2048
>
> - without this patch
> mkfs.ubifs -s 2048  -m 2048
>
> (2) Also please check for  'chip->options & NAND_NO_SUBPAGE_WRITE'.
> This flag is used for explicitely _disabling_ sub-pages in NAND driver.
>
>
>> With OMAP L138 are some complains about using the ubifs and subpage
>> access, even on uboot [1] so it don't appear to be only a linux [2] problem.
>>
>> And if the problems appear on ubifs it should affect the jffs2.
>>
>> [1] - http://lists.denx.de/pipermail/u-boot/2011-April/090072.html
> Yes, there is no subpage support in U-Boot.
> Also I hope you are using 'ubiformat' to format the NAND partition with
> UBI.img in kernel ? If that isn't the case, then I'm not sure what can be the
> problem here.
> I have tested omap2-nand with subpage enabled and
> using ubiformat. And it works fine.
>
>
>> [2] - http://comments.gmane.org/gmane.linux.davinci/23836
>>
> Also from [2] last post, there seemed to be an issue with mis-match in
> ECC scheme used between U-Boot and ECC-scheme used in Kernel.
> (But this has nothing todo with sub-pages)..
> Your logs also show ECC errors, so I suggest please make sure you are
> using same ECC scheme in kernel, as the one with which you flashed
> the image.
> ----------------------------------------
>>> [  128.344667] UBI error: ubi_io_read: error -74 (ECC error) while
>>> reading 512 bytes from PEB 2:512, read 512 bytes
>>> [  128.883945] UBI error: ubi_io_read: error -74 (ECC error) while
>>> reading 512 bytes from PEB 1766:512, read 512 bytes
>>> [  128.884072] UBI: run torture test for PEB 1766
> ----------------------------------------

Pekon,

I have verified that disabling the NAND_NO_SUBPAGE_WRITE the images that 
I have generated work.

Monday I will try test your patch and see the result with subpage.

If is clear on ubifs, we can't have it without disabling the sub page or 
apply the patch, I don't understand how this influence jffs2 partitions.

On OMAP-L138 with subpage enabled, but not supported by the 
processor/nand, JFFS2 partitions can be corrupted because of subpage 
writes ?

Thanks.

Regards,
Aníbal