From: Andrea Scian <rnd4@dave-tech.it>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: linux-mtd@lists.infradead.org
Subject: Re: [PATCH 1/2] mtd: nand: use a lower value for badblockbits when working with MLC NAND
Date: Fri, 03 Apr 2015 14:52:49 +0200 [thread overview]
Message-ID: <551E8D21.7050507@dave-tech.it> (raw)
In-Reply-To: <20150315100752.3458ccfe@bbrezillon>
Sorry for the later feedback, but unfortunately I had to move to other
stuff before coming back to this topic
Il 15/03/2015 10:07, Boris Brezillon ha scritto:
> Hi Andrea,
>
> On Fri, 6 Mar 2015 13:12:17 +0100
> rnd4@dave-tech.it wrote:
>
>> From: Andrea Scian <andrea.scian@dave.eu>
>>
>> MLC NANDs have more bit flips that SLC. When looking for bad block
>> marker we have a lot of false positive if we check for the whole byte. To
>> avoid this tolerate a few (4 here) bit flips for byte.
>
> I'm not sure sure we want to accept 4 bitflips for all MLC NANDs. IMHO
> this value should be chip dependent.
I agree
> I know there is currently no way to retrieve this information,
For this reason I just put a hardcoded value.
> so here are two suggestions:
>
> 1/ make this value depend on the required NAND ecc strength
> (badblockbits = ecc_strength / 10 ?)
> 2/ let each controller change this value after nand_scan_ident
> depending on the detected chip until we find a generic solution to
> select this value
I'll try to figure out how to solve this
Any suggestion is welcome!
Regards,
--
Andrea SCIAN
DAVE Embedded Systems
next prev parent reply other threads:[~2015-04-03 12:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-06 12:12 [PATCH 0/2] Use badblockbits-like approach in nand_bbt.c rnd4
2015-03-06 12:12 ` [PATCH 1/2] mtd: nand: use a lower value for badblockbits when working with MLC NAND rnd4
2015-03-15 9:07 ` Boris Brezillon
2015-04-03 12:52 ` Andrea Scian [this message]
2015-07-23 21:24 ` Andrea Scian
2015-07-23 22:00 ` Brian Norris
2015-03-06 12:12 ` [PATCH 2/2] mtd: nand: use nand_chip badblockbits when checking bad block pattern rnd4
2015-03-15 9:18 ` Boris Brezillon
2015-10-13 10:46 ` [PATCH 0/2] Use badblockbits-like approach in nand_bbt.c Boris Brezillon
2015-10-13 18:04 ` Brian Norris
[not found] <A765B125120D1346A63912DDE6D8B6310BF69672@NTXXIAMBX02.xacn.micron.com>
2016-03-09 14:26 ` [PATCH 1/2] mtd: nand: use a lower value for badblockbits when working with MLC NAND Boris Brezillon
2016-03-09 16:37 ` Andrea Scian
2016-03-10 2:48 ` Bean Huo 霍斌斌 (beanhuo)
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