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From: Romain Izard <romain.izard.pro@gmail.com>
Date: Thu, 21 Sep 2017 11:22:42 +0200
Message-ID: <CAGkQfmNg_oatA27xjZ57CsbntwPD893K=5bFb1gF1yp-wH-L1A@mail.gmail.com>
Subject: Re: [PATCH v2 5/9] mtd: nand: atmel: Report PMECC failures as errors
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>,
        Alexandre Belloni <alexandre.belloni@free-electrons.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        Ludovic Desroches <ludovic.desroches@microchip.com>,
        Wenyou Yang <wenyou.yang@atmel.com>,
        Josh Wu <rainyfeeling@outlook.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
        Thierry Reding <thierry.reding@gmail.com>,
        Richard Genoud <richard.genoud@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Alan Stern <stern@rowland.harvard.edu>, linux-pwm@vger.kernel.org,
        linux-usb@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        linux-mtd <linux-mtd@lists.infradead.org>,
        linux-serial@vger.kernel.org, linux-clk@vger.kernel.org,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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2017-09-18 12:00 GMT+02:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
> Hi Romain,
>
> On Fri, 15 Sep 2017 16:04:07 +0200
> Romain Izard <romain.izard.pro@gmail.com> wrote:
>
>> It is not normal for the PMECC to fail when trying to fix ECC errors.
>> Report these cases as errors.
>
> I'm not sure we want to have ECC error messages at this level. ECC
> errors are rather unusual but not impossible, and sometimes it's even
> not a real error (I'm thinking of bitflips in erased pages for
> example, which are not necessarily detected/fixed in hardware).
>
> If we decide to print error messages when unfixable bitflips are
> detected, it should be done in the nand-controller driver (somewhere
> along those lines [1]).
>
> Regards,
>
> Boris
>
> [1]http://elixir.free-electrons.com/linux/latest/source/drivers/mtd/nand/atmel/nand-controller.c#L827
>
>>
>> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
>> ---
>>  drivers/mtd/nand/atmel/pmecc.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/nand/atmel/pmecc.c b/drivers/mtd/nand/atmel/pmecc.c
>> index 8d1208f38025..2a23f1ff945f 100644
>> --- a/drivers/mtd/nand/atmel/pmecc.c
>> +++ b/drivers/mtd/nand/atmel/pmecc.c
>> @@ -687,6 +687,8 @@ static int atmel_pmecc_err_location(struct atmel_pmecc_user *user)
>>        * Number of roots does not match the degree of smu
>>        * unable to correct error.
>>        */
>> +     dev_err(pmecc->dev,
>> +             "PMECC: Impossible to calculate error location.\n");
>>       return -EBADMSG;
>>  }
>>
>> @@ -729,7 +731,7 @@ int atmel_pmecc_correct_sector(struct atmel_pmecc_user *user, int sector,
>>                       ptr = ecc + byte - sectorsize;
>>                       area = "ECC";
>>               } else {
>> -                     dev_dbg(pmecc->dev,
>> +                     dev_err(pmecc->dev,
>>                               "Invalid errpos value (%d, max is %d)\n",
>>                               errpos, (sectorsize + eccbytes) * 8);
>>                       return -EINVAL;
>

Ok, I will drop this patch.