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Message-ID: <54954C88.7020705@rempel-privat.de>
Date: Sat, 20 Dec 2014 11:16:40 +0100
From: Oleksij Rempel <linux@rempel-privat.de>
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To: Richard Weinberger <richard@nod.at>, t kevin <kevint324@gmail.com>,
 linux-mtd@lists.infradead.org
Subject: Re: Get error -74 (ECC error) during ubiattach
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Am 20.12.2014 um 11:12 schrieb Richard Weinberger:
> Am 20.12.2014 um 11:05 schrieb Oleksij Rempel:
>> Am 20.12.2014 um 11:02 schrieb Richard Weinberger:
>>> Am 20.12.2014 um 11:00 schrieb Oleksij Rempel:
>>>> Am 20.12.2014 um 10:27 schrieb Richard Weinberger:
>>>>> Hi!
>>>>>
>>>>> Am 20.12.2014 um 04:43 schrieb t kevin:
>>>>>> So for uncorrectable ECC error ( e.g., bad block) the only way out=
 is
>>>>>> to do a fresh ubiformat?
>>>>>> For device like harddisk you get bad blocks all the time, if it is=
 not
>>>>>> in the critical sector things can be fixed as much as possible by =
fsck
>>>>>> so I was looking for something like fsck.ubifs.
>>>>>
>>>>> An uncorrectable ECC error means that more bits flipped than your E=
CC
>>>>> algorithm can fix.
>>>>
>>>> At same time uncorrectable ECC error mean, the page was erase and th=
ere
>>>> is no ECC sum. Something should be written to create ECC.
>>>
>>> Which would be a driver bug and needs fixing.
>>
>> No at all. If driver get request to erase page, it should do it and
>> nothing more.
>> There are use cases where erase means erase, and not erase + write ecc=
=2E
>=20
> Raw mode is a different thing.

There is no raw erase mode in this api.

>> It is not a driver bug!
>=20
> If users on top of MTD read from an erased block it has to return 0xFF =
bytes and
> not an ECC error.
> IOW if mtd_erase() -> mtd_read() causes an ECC error with your driver i=
t needs
> fixing.


check out this code:
https://github.com/olerem/linux-2.6/blob/uparm_9260-2014.12.17.1/drivers/=
mtd/nand/nand_base.c#L2686

This commands passed to flash chip. There is nothing about erase and
write ecc.

--=20
Regards,
Oleksij


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