UBI 1MiB size partition

[Artem Bityutskiy]

On Fri, 2014-11-28 at 10:49 +0100, Angelo Dureghello wrote:
> Dear Artem,
> 
> thanks for your reply.
> 
> > UBI is a volume manager which is designed to manage the entire flash
> > chip. Sometimes system designers have one or two small partitions at the
> > beginning of the chip, and give the rest to UBI.
> >
> > You are using NAND flash, and UBI tries to reserve some amount of
> > eraseblocks for bad block handling. And the count of eraseblocks to
> > reserve is calculated from the entire chip size. So UBI says it wants
> > 20, but reserved only 4 - all the available blocks you have. So you do
> > not have any more blocks left, so you have no space.
> >
> > You really should re-think your design. 1MiB partition is too small,
> > there are too few eraseblocks. What if one or two of them become bad?
> >
> Yes, i realized this. A redesign of the partition scheme is needed at this
> stage.
> I cannot actually change the partition scheme for some reasons connected
> to the production process, but at least things are more clear now.

Not that I recommend this for your design, but if you want to play with
your 1MiB partition, you may try the max_beb_per1024 UBI parameter, or
the CONFIG_MTD_UBI_BEB_LIMIT option. I did not try, but hopefully it
allows you to specify 0?