[Yaffs-archive] RE: YAFFS update -->CONFIG_YAFFS_VERIFY_WRITE

[Charles Manning]

>Hurrah,
>BTW, Charles, should it be possible to have have an option that make 
>conditional
>the readback and verify in yaffs_WriteNewChunckToNand() (eg.
>CONFIG_YAFFS_VERIFY_WRITE)?

Luc,

I could put this in, but I am very reluctant to do this.

NAND programming only fails if a 1 bit could not change to a 0 bit. However,
if some how extra bits got changed to zero (eg. due to broken flash), this
is not reported as a progamming failure. Verification provides the only
reliable way to do this checking.

If you're doing this for performance reasons I would suggest that you rather
look for other ways to find performance (eg. unwind the byte-copy loops in
the NAND access layer).

Compromise: 
*I will put this in as an option, but with a severe warning.
* I will also add a printk to the yaffs module initialisation message to
show what options are enabled.
*If you experience any yaffs_guts problems, my first question will be: "Is
CONFIG_YAFFS_VERIFY_WRITE enabled?". If not, come back when you experience
the problem with this enabled.

-- Charles


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