Re: mtd_nandbiterrs errors

[JH <jupiter.hce@xxxxxxxxx>]

Hi Steve,

Glad you help me here as well :-)

On 2/6/20, Steve deRosier <derosier@xxxxxxxxx> wrote:
> ECC is dependant on the device. And it can't be mixed-and-matched.
> Every device has a datasheet that will tell you the minimum required.
> You can (and usually should) go more than the minimum required, up to
> however much you can fit in the OOB area. There's several ways to
> check it, one way is to dump a programed page via u-boot `nand dump`
> command from each partition and see how much of the OOB is taken up by
> ECC bits. Personally, I'd do that even if I thought I knew what the
> setting is supposed to be to validate that the data was actually
> written in correctly. Depending on your system, you can find the
> configured strength in your DTS. And also the u-boot config for your
> platform (boot loader and kernel need to agree on ECC settings).

Just got a dts file, it uses fsl,use-minimum-ecc, I think that dts was
copied from original imx6ull EVK, it looks like it is 4 bits.

Sorry for a silly question, how could I run command in u-boot and
Linux to verify the ECC strength bits and setting in u-boot and Linux?

> You need to find the datasheets for your devices, it will tell you
> what you need to know.

The datasheet says "The system has to use a minimum 1-bit ECC per 528
bytes of data to ensure data recovery". For 2KB page size, I guess a 4
bits should be adequate, right? I need to find a way to run commands
in u-boot and Linux to find the ECC bits.

Thank you so much Steve,

Kind regards,

- jh

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