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Date:   Tue, 23 Mar 2021 15:06:03 +0100
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Daniel Palmer <daniel@0x0f.com>
Cc:     linux-mtd@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mtd: spinand: add support for Foresee FS35ND01G-S1Y2
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Hi Daniel,

Daniel Palmer <daniel@0x0f.com> wrote on Tue, 23 Mar 2021 20:47:10
+0900:

> Hi Miquel,
> 
> On Tue, 23 Mar 2021 at 19:32, Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> > You can run nandbiterrs -i /dev/mtdX
> >
> > You'll see if there is ECC correction or not (and its level).  
> 
> These are results I get for both of the nandbiterrs tests.
> 
> # nandbiterrs -i /dev/mtd1
> incremental biterrors test
> Successfully corrected 0 bit errors per subpage
> Inserted biterror @ 0/5
> Read reported 4 corrected bit errors
> ECC failure, invalid data despite read success

This is not a valid behavior. There is something wrong with the way ECC
status is read/retrieved. The read should indeed report 4 corrected bit
errors, but then the data should be valid. Here it means that the
introduced error appears corrected but in fact is not.

We need to understand what status are available and write the
appropriate vendor code.

Thanks,
Miquèl