Bad Blocks On JFFS2/NAND

[Simon Haynes]

Thomas,

I am using the ready pin.

On Tuesday 19 Oct 2004 12:50 pm, Thomas Gleixner wrote:
> On Tue, 2004-10-19 at 13:22, Simon Haynes wrote:
> > I have experienced a problem in which a JFF2 filesystem on NAND became
> > full. This is a root file system and constant writes to a logfile filled
> > the filesystem. On investigation it was found that the NAND device now
> > had hundreds of bad blocks.
> >
> > I started to investigate this and found that JFFS2 was announcing
> >
> > Newly-erased block contained word 0x1985e002 at offset 0x020f7e00
> >
> > Messages which result in my mtd/jffs2 code marking the block bad. What I
> > find strange is that a subsequent scan list the new block at a different
> > 16k offset when the device erasesize is 16k, in this case 0x020f0000. Is
> > that because my device is 128Mb and JFFS2 is using this 'virtual erase
> > size' of 32k ?
>
> Yes. The bad block code scans/marks physical blocks and JFFS2 operates
> on virtual ones, if the device size is big enough.
>
> > I have observed this now on several different NAND devices and it seems
> > to be more prominent while performing small writes.
> >
> > I am currently trying to work out if the erase is not completing, or this
> > is the wrong block or something else.
>
> Hmm, are you using Ready/Busy Pin or the timeout ?
>
> tglx
>
>
>
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