[Yaffs] yaffs: NAND not properly erased or other problems...

Hi all,



I'm currently trying to use YAFFS2 on a NAND flash running linux 2.6.17. I
noticed the following behavior and would like to know if this is normal or
if I need to do something to fix it.



When I first mount the NAND partition and write to it I have a lot of these
messages:



**>> yaffs chunk 1215 was not erased

**>> yaffs write required 2 attempts



On some of the file (including the init file.. this is a bootable
filesystem). If I disregard these messages and unmount/reboot on it the
files affected by the YAFFS CHUNK messages are unusable (nothing in the
lost+found though)



Now, if instead of rebooting right away, I try to rewrite the files once
more I get these messages..



page 8704 in gc has no object

**>> Block 136 retired

page 8774 in gc has no object



and then (stay with me here please). If I re-rewrite the same files, I have
absolutely no message whatsoever, the files are written correctly to the
filesystem and I can boot on the FS and use the files perfectly.. The only
thing is that all these blocks that were retired are now marked as bad.. so
I have like 25 bad blocks on the filesystem..



I have the same behavior on different boards (different NAND flash chips), I
even modified a version of the flash_eraseall to erase the bad blocks so I
start with a fresh empty BBT on the flash and I can recreate exactly the
same behavior.



So.. I would like to know what's going on here exactly?



* Do I really have that many bad blocks on all the NAND chips?

* Do I have trouble erasing correctly (yaffs chunk was not erased messages)?



All comments welcome.



Boris