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Date: Mon, 13 May 2013 22:21:58 +0530
From: Vikram Narayanan <vikram186@gmail.com>
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To: Huang Shijie <b32955@freescale.com>
Subject: Re: mtd_oobtest fails with GPMI-NAND
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Hello Huang,

On 5/13/2013 2:31 PM, Huang Shijie wrote:
>>
>> Huang, is this to be expected? How does this look on one of your
>> officially "supported" imx6 boards with NAND support?
>>
> I suggest you do not use the mtd_nandbiterrs.ko. It will call the
> mtd_write_oob() which will definitely lead to the
> -EBADMSG (-74) error.
>
> The mtd_write_oob() in mtd_nandbiterrs.ko writes a whole page without
> enabling the BCH to do the hardware ECC.
> But mtd_read() in mtd_nandbiterrs.ko DOES do the hardware ECC by the BCH.
> It's normal that you meet -74.

I wonder if this has something to do with the fake
"struct nand_ecclayout" defined in
<drivers/mtd/nand/gpmi-nand/gpmi-nand.c>?

Could you please explain on what is the technical restriction for not 
providing a _sane_ ecclayout structure, so that the mtd_tests run happily?

Regards,
Vikram