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Date: Tue, 12 Jun 2012 06:23:29 -0700
From: Mike Dunn <mikedunn@newsguy.com>
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To: Brian Norris <computersforpeace@gmail.com>
Subject: Re: [PATCH] mtd: nand: ignore ecc errors during bbt reads
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Cc: linux-mtd@lists.infradead.org, Shmulik Ladkani <shmulik.ladkani@gmail.com>,
 dedekind1@gmail.com
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On 06/10/2012 10:45 PM, Brian Norris wrote:
> 
> On Sun, Jun 10, 2012 at 4:50 AM, Shmulik Ladkani
> <shmulik.ladkani@gmail.com> wrote:
>> On Thu,  7 Jun 2012 11:32:08 -0700 Mike Dunn <mikedunn@newsguy.com> wrote:
>>> Ignore ecc errors in the scan_read_raw_oob() function.  Also removed code that
>>> is now redundant.
>>>
>>> Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
>>> ---
>>>  drivers/mtd/nand/nand_bbt.c |    6 +++---
>>>  1 files changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
>>> index 30d1319..585da44 100644
>>> --- a/drivers/mtd/nand/nand_bbt.c
>>> +++ b/drivers/mtd/nand/nand_bbt.c
>>> @@ -319,7 +319,8 @@ static int scan_read_raw_oob(struct mtd_info *mtd, uint8_t *buf, loff_t offs,
>>>
>>>               res = mtd_read_oob(mtd, offs, &ops);
>>>
>>> -             if (res)
>>> +             /* Ignore ECC errors when checking for BBM */
>>> +             if (res && !mtd_is_bitflip_or_eccerr(res))
>>>                       return res;
>>
>> IMO this is not necessary.
>> Note the 'ops.mode' is initialized to MTD_OPS_RAW;  meaning, no ECC is
>> performed during read ('ecc.read_page_raw' will be invoked).
>> Thus, EUCLEAN/EBADMSG should not be reported.
>> Am I missing something here?
> 
> Shmulik is correct. A check for bitflips on a MTD_OPS_RAW operation is
> unnecessary.


Yes, I missed the ops mode raw.  Obviously my analysis was wrong.

Good that nand_bbt is getting cleaned up some.

Thanks again Brian and Shmulik.

Mike