Re: [PATCH 1/1] mtd: mtdram: Add parameter for setting writebuf size

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Wednesday 02 March 2016 13:47:50, Richard Weinberger wrote:
> Am 02.03.2016 um 11:41 schrieb Alexander Stein:
> > On Wednesday 02 March 2016 11:23:59, Richard Weinberger wrote:
> >> On Wed, Mar 2, 2016 at 10:45 AM, Alexander Stein
> >> <alexander.stein@systec-electronic.com> wrote:
> >>> ubifs uses the write buffer size in recovery algorithm. When inspecting
> >>> an unclean ubifs recovery fails with writebuf size 64 in mtdram while
> >>> recovery on actual mtd device with writebuf size of 1024 succeeds.
> >>> So add a parameter for setting this property.
> >>
> >> Can it be that you've tested an NAND image on mtdram?
> > 
> > Nope. We copied that image within barebox from device /dev/nor0 (the whole 128MiB NOR flash) and used that in mtdram.
> > Unfortunately mounting that "broken" ubifs in barebox suffers from essentially the same problem: using a different writebuf size for recovery results in failure. But that's another issue.
> > The apparently important changes in linux are the commits:
> > 428ff9d2e37d3a82af0f56b476f70c244cf550d1 ("UBIFS: remove dead code")
> > 2765df7da540687c4d57ca840182122f074c5b9c ("UBIFS: use max_write_size during recovery")
> > With those two the writebuf size gets used by ubifs.
> 
> Makes sense to me!
> One minor nitpick, the comment "Mimic CFI NOR flashes" is no longer valid then.
> Maybe you can note in Kconfig that the default value 64 mimics CFI NOR...

Well, I stumbled also on that because we actually do use a CFI NOR flash. The commit message introducing that states: "Set the 'mtd->writebufsize' field to 64 to mimic modern CFI flashes." I guess 64 Bytes was modern at that time. I'll remove it all together in v2.

> Beside of that:
> Reviewed-by: Richard Weinberger <richard@nod.at>

Thanks, best regards,
Alexander
-- 
Dipl.-Inf. Alexander Stein
SYS TEC electronic GmbH
alexander.stein@systec-electronic.com

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