UBIFS and hardware ECC of all FF pages of MLC NAND

[Artem Bityutskiy]

On Thu, 2009-09-24 at 17:36 +0200, Matthieu CASTET wrote:
> Adrian Hunter a écrit :
> > Darwin Rambo wrote:
> > 
> >> 2. for initial downloading, should an ECC be programmed on all FF data pages? Is there any correction advantage?
> > 
> > In your case, as you have discovered, you must not program ECC for FF pages at
> > the end of eraseblocks.
> > 
> The tricky part is when you read FF pages with ecc in mtd. You will get
> an ecc error.
> 
> If the ecc writing is done on software you can always xor the ecc code
> to make it "FF for FF data".
> But if everything is done by hardware...

Right, which means the UBI/UBIFS flasher should be smart and skip
0xFF-ed NAND pages at the end of eraseblocks. This adds some complexity
to the flasher, thought. And here:

http://www.linux-mtd.infradead.org/doc/ubi.html#L_format_det

I even described in details the flashing algorithm with my limited
English vocabulary :-)

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)