No oob scheme defined for oobsize 218

No oob scheme defined for oobsize 218

[Joo Aun Saw]

Hi all,

I'm getting this error and hope someone can help me.

ONFI flash detected
ONFI param page 0 valid
NAND device: Manufacturer ID: 0x2c, Chip ID: 0xd3 (Micron MT29F8G08AAA)
No oob scheme defined for oobsize 218

Do I need to define struct nand_ecclayout nand_oob_218? or can I use
the nand_oob_128 ecc layout?
I'm running Linux version 3.0.4.

Thanks in advance.

Re: No oob scheme defined for oobsize 218

[Brian Norris]

On Sun, Jan 8, 2012 at 10:34 PM, Joo Aun Saw <jasaw@dius.com.au> wrote:
> I'm getting this error and hope someone can help me.
>
> ONFI flash detected
> ONFI param page 0 valid
> NAND device: Manufacturer ID: 0x2c, Chip ID: 0xd3 (Micron MT29F8G08AAA)
> No oob scheme defined for oobsize 218
>
> Do I need to define struct nand_ecclayout nand_oob_218? or can I use
> the nand_oob_128 ecc layout?
> I'm running Linux version 3.0.4.

This may depend on what hardware/driver, what type of ECC you're
using, and what filesystem you're using on top of your MTD. It's
possible you can get by with just using a "smaller" ECC layout,
especially if you're not using the OOB area for filesystem data (e.g.,
UBI(FS), which doesn't use OOB). You just won't have as much "free"
OOB area (again, doesn't matter much for UBI(FS)) and your ECC layout
might not reflect the actual positioning of your ECC data.

Brian

Re: No oob scheme defined for oobsize 218

[Joo Aun Saw]

I'm running UBI(FS) on top of it, so I don't need the OOB area. In
this case, what's the best way to work around this problem? Should I
use a smaller ECC layout or disable ECC?

How is the ECC layout defined, as in what decides how big the
eccbytes, eccpos, oobfree should be?




On Tue, Jan 10, 2012 at 4:36 AM, Brian Norris
<computersforpeace@gmail.com> wrote:
> On Sun, Jan 8, 2012 at 10:34 PM, Joo Aun Saw <jasaw@dius.com.au> wrote:
>> I'm getting this error and hope someone can help me.
>>
>> ONFI flash detected
>> ONFI param page 0 valid
>> NAND device: Manufacturer ID: 0x2c, Chip ID: 0xd3 (Micron MT29F8G08AAA)
>> No oob scheme defined for oobsize 218
>>
>> Do I need to define struct nand_ecclayout nand_oob_218? or can I use
>> the nand_oob_128 ecc layout?
>> I'm running Linux version 3.0.4.
>
> This may depend on what hardware/driver, what type of ECC you're
> using, and what filesystem you're using on top of your MTD. It's
> possible you can get by with just using a "smaller" ECC layout,
> especially if you're not using the OOB area for filesystem data (e.g.,
> UBI(FS), which doesn't use OOB). You just won't have as much "free"
> OOB area (again, doesn't matter much for UBI(FS)) and your ECC layout
> might not reflect the actual positioning of your ECC data.
>
> Brian

Re: No oob scheme defined for oobsize 218

[Brian Norris]

Hi,

Please reply below any quotations and only repeat what is necessary,
according to the etiquette notes #4 and #6 on:
http://www.infradead.org/~dwmw2/email.html

On Mon, Jan 9, 2012 at 4:16 PM, Joo Aun Saw <jasaw@dius.com.au> wrote:
> I'm running UBI(FS) on top of it, so I don't need the OOB area. In
> this case, what's the best way to work around this problem? Should I
> use a smaller ECC layout or disable ECC?

Do not disable ECC, but a smaller ECC layout probably will work OK.
It's not perfect, but I don't know of any common UBIFS-related
features that would make use of the layout anyway.

> How is the ECC layout defined, as in what decides how big the
> eccbytes, eccpos, oobfree should be?

This is why I mentioned that your answer depends on "hardware/driver
and what type of ECC you're
using". Either mention your specs or try studying the defaults in
nand_base.c and maybe the definition in include/linux/mtd/mtd.h.
Layout structs basically should describe what offsets within the OOB
are used by ECC (in eccpos), how much OOB is used by ECC (eccbytes),
and the position and length of OOB segments that are unused by ECC and
bad block markers (oobfree struct).

Brian

Re: No oob scheme defined for oobsize 218

[Artem Bityutskiy]

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On Mon, 2012-01-09 at 17:34 +1100, Joo Aun Saw wrote:
> Hi all,
> 
> I'm getting this error and hope someone can help me.
> 
> ONFI flash detected
> ONFI param page 0 valid
> NAND device: Manufacturer ID: 0x2c, Chip ID: 0xd3 (Micron MT29F8G08AAA)
> No oob scheme defined for oobsize 218
> 
> Do I need to define struct nand_ecclayout nand_oob_218? or can I use
> the nand_oob_128 ecc layout?
> I'm running Linux version 3.0.4.

Please, be aware of the unstable bits UBIFS problem - it is still not
resolved and no one is working on this AFAIK. This issue may cause
unrecoverable corruptions after power cuts. Someone should invest few
men-months to fix this.

See: http://www.linux-mtd.infradead.org/doc/ubifs.html#L_unstable_bits

Artem.


-- 
Best Regards,
Artem Bityutskiy

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