[U-Boot] Fat write problem

[Detlev Zundel <dzu@denx.de>]

Hi Ruud,

> This week I decided to do some further research and testing regarding
> this problem.
> With the image I had from the previous time, I could immediately
> reproduce it and
> by adding more and more debug prints, I tried to find the cause. Sofar,
> I have not
> succeeded in this yet.
>
> However: later on I started testing with a freshly formatted drive (32
> MB FAT partition)
> and kept repeating the fatwrite command:
>
> fatwrite mmc 0:1 42000000 test-x 200
>
> where x runs from 1, 2,3 and further. And this way I could reproduce it
> quite easily.
> Writing always fails for the 32nd file. This is with the partition
> formatted with a 512 byte
> sector size and a cluster size of 4. If the cluster size is 1 (formatted
> by Windows),
> it already fails at the 8th file.
>
> If I create a subdirectory (from Linux) with already 24 files in it, I
> can still write 29 files
> and it fails at number 30. Also, if earlier files were deleted from the
> root-directory, they
> still count in the total number of files here.
>
> If I take out the card where u-boot fails to write new files, I can
> still add new files from
> my PC with Linux or Windows.
>
> I tested with both long and short filenames (same result), VFAT is
> enabled.
>
> I hope this gives you all some more information about this problem and
> perhaps it is even a
> known problem (limited number of files in the root directory?). I know
> it is voor FAT16, but
> that was 512 entries if I am correct.

Thanks for the extensive research into this problem.  For people to
help, I think the barrier of reproducing the problem is "somewhat
high", so it occurred to me if you can help setup a very easy test for
people to work on.  Would you be able to generate a small image that one
can dd to a mmc card and then immediately provoke the error?  If you
don't have any hosting space, as a last resort I'd be fine for you to
put it on our wiki [1].

Cheers
  Detlev

[1] http://www.denx.de/wiki/view/U-Boot/TooBigPatches

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