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* help with mtd-test failures?
@ 2015-01-03  2:34 Steve deRosier
  2015-01-04  8:15 ` Josh Wu
  0 siblings, 1 reply; 3+ messages in thread
From: Steve deRosier @ 2015-01-03  2:34 UTC (permalink / raw)
  To: linux-mtd

Hi all,

In doing my due dillegence on my system, I decided to run the
mtd-tests. I'm getting a few failures that I'd like your help in
understanding.

The one that worries me comes from mtd_oobtest:

    # modprobe mtd_oobtest dev=7
    mtd_oobtest: error: verify failed at 0x880000
    mtd_oobtest: error: verify failed at 0xe80000

The most worrysome thing about this is the fact that the result isn't
consistant. sometimes I get no failures, and sometimes they're at
different spots. I'll put the kmesg output later.

The other one is less concerning, but what do these failures from
mtd_nandecctest indicate?

    mtd_nandecctest: ok - no-bit-error-256
    mtd_nandecctest: ok - single-bit-error-in-data-correct-256
    mtd_nandecctest: ok - single-bit-error-in-ecc-correct-256
    uncorrectable error :
    mtd_nandecctest: ok - double-bit-error-in-data-detect-256
    uncorrectable error :
    mtd_nandecctest: ok - single-bit-error-in-data-and-ecc-detect-256
    uncorrectable error :
    mtd_nandecctest: ok - double-bit-error-in-ecc-detect-256
    mtd_nandecctest: ok - no-bit-error-512
    mtd_nandecctest: ok - single-bit-error-in-data-correct-512
    mtd_nandecctest: ok - single-bit-error-in-ecc-correct-512
    uncorrectable error :
    mtd_nandecctest: ok - double-bit-error-in-data-detect-512
    uncorrectable error :
    mtd_nandecctest: ok - single-bit-error-in-data-and-ecc-detect-512
    uncorrectable error :
    mtd_nandecctest: ok - double-bit-error-in-ecc-detect-512

I'm not very concerned because I believe from looking at the comments
that this doesn't actually utilize my hardware but is a software ECC
test and I'm using a hardware-based ECC.

My kernel version is 3.8.  I'm running on an Atmel SAM9G25 processor
with a Micron MT29F1G08ABBEAH4 SLC NAND.

All of the rest of the tests ran perfectly. And, are there any other
tests I should run to validate my hardware, kernel/driver setup, or
UBIFS?

The kmesg for the mtd_oobtest:

    =================================================
    mtd_oobtest: MTD device: 7
    mtd_oobtest: MTD device size 39845888, eraseblock size 131072,
page size 2048, count of eraseblocks 304, pages per eraseblock 64, OOB
size 64
    mtd_oobtest: scanning for bad eraseblocks
    mtd_oobtest: scanned 304 eraseblocks, 0 are bad
    mtd_oobtest: test 1 of 5
    mtd_oobtest: erasing whole device
    mtd_oobtest: erased 304 eraseblocks
    mtd_oobtest: writing OOBs of whole device
    mtd_oobtest: written up to eraseblock 0
    mtd_oobtest: written up to eraseblock 256
    mtd_oobtest: written 304 eraseblocks
    mtd_oobtest: verifying all eraseblocks
    mtd_oobtest: verified up to eraseblock 0
    mtd_oobtest: verified up to eraseblock 256
    mtd_oobtest: verified 304 eraseblocks
    mtd_oobtest: test 2 of 5
    mtd_oobtest: erasing whole device
    mtd_oobtest: erased 304 eraseblocks
    mtd_oobtest: writing OOBs of whole device
    mtd_oobtest: written up to eraseblock 0
    mtd_oobtest: written up to eraseblock 256
    mtd_oobtest: written 304 eraseblocks
    mtd_oobtest: verifying all eraseblocks
    mtd_oobtest: verified up to eraseblock 0
    mtd_oobtest: error: verify failed at 0x880000
    mtd_oobtest: error: verify failed at 0xe80000
    mtd_oobtest: verified up to eraseblock 256
    mtd_oobtest: verified 304 eraseblocks
    mtd_oobtest: test 3 of 5
    mtd_oobtest: erasing whole device
    mtd_oobtest: erased 304 eraseblocks
    mtd_oobtest: writing OOBs of whole device
    mtd_oobtest: written up to eraseblock 0
    mtd_oobtest: written up to eraseblock 256
    mtd_oobtest: written 304 eraseblocks
    mtd_oobtest: verifying all eraseblocks
    mtd_oobtest: verified up to eraseblock 0
    mtd_oobtest: verified up to eraseblock 256
    mtd_oobtest: verified 304 eraseblocks
    mtd_oobtest: test 4 of 5
    mtd_oobtest: erasing whole device
    mtd_oobtest: erased 304 eraseblocks
    mtd_oobtest: attempting to start write past end of OOB
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: attempting to start read past end of OOB
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: attempting to write past end of device
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: attempting to read past end of device
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: attempting to write past end of device
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: attempting to read past end of device
    mtd_oobtest: an error is expected...
    mtd_oobtest: error occurred as expected
    mtd_oobtest: test 5 of 5
    mtd_oobtest: erasing whole device
    mtd_oobtest: erased 304 eraseblocks
    mtd_oobtest: writing OOBs of whole device
    mtd_oobtest: written up to eraseblock 0
    mtd_oobtest: written up to eraseblock 0
    mtd_oobtest: written up to eraseblock 256
    mtd_oobtest: written up to eraseblock 256
    mtd_oobtest: written 303 eraseblocks
    mtd_oobtest: verifying all eraseblocks
    mtd_oobtest: verified up to eraseblock 0
    mtd_oobtest: verified up to eraseblock 256
    mtd_oobtest: verified 303 eraseblocks
    mtd_oobtest: finished with 2 errors
    =================================================

Thanks,
- Steve

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: help with mtd-test failures?
  2015-01-03  2:34 help with mtd-test failures? Steve deRosier
@ 2015-01-04  8:15 ` Josh Wu
  2015-01-09  5:05   ` Steve deRosier
  0 siblings, 1 reply; 3+ messages in thread
From: Josh Wu @ 2015-01-04  8:15 UTC (permalink / raw)
  To: linux-mtd

Hi, Steve

On 1/3/2015 10:34 AM, Steve deRosier wrote:
> Hi all,
>
> In doing my due dillegence on my system, I decided to run the
> mtd-tests. I'm getting a few failures that I'd like your help in
> understanding.
>
> The one that worries me comes from mtd_oobtest:
>
>      # modprobe mtd_oobtest dev=7
>      mtd_oobtest: error: verify failed at 0x880000
>      mtd_oobtest: error: verify failed at 0xe80000
>
> The most worrysome thing about this is the fact that the result isn't
> consistant. sometimes I get no failures, and sometimes they're at
> different spots.
I think this should be related with nand flash's bitflips. As atmel nand 
driver just use standard oob write/read functions from nand_base.c.
That means there is no ecc protection for mtd_oobtest.
So if there has any nand bitflip happens in the oob area, then 
mtd-oobtest will be failed.

How often does the failures comes?
I tested on my at91sam9g25ek board (nand is: 29F2G08AAD) about 20 times, 
no error happened.

> I'll put the kmesg output later.
>
> The other one is less concerning, but what do these failures from
> mtd_nandecctest indicate?
>
>      mtd_nandecctest: ok - no-bit-error-256
>      mtd_nandecctest: ok - single-bit-error-in-data-correct-256
>      mtd_nandecctest: ok - single-bit-error-in-ecc-correct-256
>      uncorrectable error :
>      mtd_nandecctest: ok - double-bit-error-in-data-detect-256
>      uncorrectable error :
>      mtd_nandecctest: ok - single-bit-error-in-data-and-ecc-detect-256
>      uncorrectable error :
>      mtd_nandecctest: ok - double-bit-error-in-ecc-detect-256
>      mtd_nandecctest: ok - no-bit-error-512
>      mtd_nandecctest: ok - single-bit-error-in-data-correct-512
>      mtd_nandecctest: ok - single-bit-error-in-ecc-correct-512
>      uncorrectable error :
>      mtd_nandecctest: ok - double-bit-error-in-data-detect-512
>      uncorrectable error :
>      mtd_nandecctest: ok - single-bit-error-in-data-and-ecc-detect-512
>      uncorrectable error :
>      mtd_nandecctest: ok - double-bit-error-in-ecc-detect-512
>
> I'm not very concerned because I believe from looking at the comments
> that this doesn't actually utilize my hardware but is a software ECC
> test and I'm using a hardware-based ECC.
yes, this one is a software ecc test.

Best Regards,
Josh Wu

>
> My kernel version is 3.8.  I'm running on an Atmel SAM9G25 processor
> with a Micron MT29F1G08ABBEAH4 SLC NAND.
>
> All of the rest of the tests ran perfectly. And, are there any other
> tests I should run to validate my hardware, kernel/driver setup, or
> UBIFS?
>
> The kmesg for the mtd_oobtest:
>
>      =================================================
>      mtd_oobtest: MTD device: 7
>      mtd_oobtest: MTD device size 39845888, eraseblock size 131072,
> page size 2048, count of eraseblocks 304, pages per eraseblock 64, OOB
> size 64
>      mtd_oobtest: scanning for bad eraseblocks
>      mtd_oobtest: scanned 304 eraseblocks, 0 are bad
>      mtd_oobtest: test 1 of 5
>      mtd_oobtest: erasing whole device
>      mtd_oobtest: erased 304 eraseblocks
>      mtd_oobtest: writing OOBs of whole device
>      mtd_oobtest: written up to eraseblock 0
>      mtd_oobtest: written up to eraseblock 256
>      mtd_oobtest: written 304 eraseblocks
>      mtd_oobtest: verifying all eraseblocks
>      mtd_oobtest: verified up to eraseblock 0
>      mtd_oobtest: verified up to eraseblock 256
>      mtd_oobtest: verified 304 eraseblocks
>      mtd_oobtest: test 2 of 5
>      mtd_oobtest: erasing whole device
>      mtd_oobtest: erased 304 eraseblocks
>      mtd_oobtest: writing OOBs of whole device
>      mtd_oobtest: written up to eraseblock 0
>      mtd_oobtest: written up to eraseblock 256
>      mtd_oobtest: written 304 eraseblocks
>      mtd_oobtest: verifying all eraseblocks
>      mtd_oobtest: verified up to eraseblock 0
>      mtd_oobtest: error: verify failed at 0x880000
>      mtd_oobtest: error: verify failed at 0xe80000
>      mtd_oobtest: verified up to eraseblock 256
>      mtd_oobtest: verified 304 eraseblocks
>      mtd_oobtest: test 3 of 5
>      mtd_oobtest: erasing whole device
>      mtd_oobtest: erased 304 eraseblocks
>      mtd_oobtest: writing OOBs of whole device
>      mtd_oobtest: written up to eraseblock 0
>      mtd_oobtest: written up to eraseblock 256
>      mtd_oobtest: written 304 eraseblocks
>      mtd_oobtest: verifying all eraseblocks
>      mtd_oobtest: verified up to eraseblock 0
>      mtd_oobtest: verified up to eraseblock 256
>      mtd_oobtest: verified 304 eraseblocks
>      mtd_oobtest: test 4 of 5
>      mtd_oobtest: erasing whole device
>      mtd_oobtest: erased 304 eraseblocks
>      mtd_oobtest: attempting to start write past end of OOB
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: attempting to start read past end of OOB
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: attempting to write past end of device
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: attempting to read past end of device
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: attempting to write past end of device
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: attempting to read past end of device
>      mtd_oobtest: an error is expected...
>      mtd_oobtest: error occurred as expected
>      mtd_oobtest: test 5 of 5
>      mtd_oobtest: erasing whole device
>      mtd_oobtest: erased 304 eraseblocks
>      mtd_oobtest: writing OOBs of whole device
>      mtd_oobtest: written up to eraseblock 0
>      mtd_oobtest: written up to eraseblock 0
>      mtd_oobtest: written up to eraseblock 256
>      mtd_oobtest: written up to eraseblock 256
>      mtd_oobtest: written 303 eraseblocks
>      mtd_oobtest: verifying all eraseblocks
>      mtd_oobtest: verified up to eraseblock 0
>      mtd_oobtest: verified up to eraseblock 256
>      mtd_oobtest: verified 303 eraseblocks
>      mtd_oobtest: finished with 2 errors
>      =================================================
>
> Thanks,
> - Steve
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: help with mtd-test failures?
  2015-01-04  8:15 ` Josh Wu
@ 2015-01-09  5:05   ` Steve deRosier
  0 siblings, 0 replies; 3+ messages in thread
From: Steve deRosier @ 2015-01-09  5:05 UTC (permalink / raw)
  To: Josh Wu; +Cc: linux-mtd@lists.infradead.org

Thanks Josh,


On Sun, Jan 4, 2015 at 12:15 AM, Josh Wu <josh.wu@atmel.com> wrote:
> Hi, Steve
>
> On 1/3/2015 10:34 AM, Steve deRosier wrote:
>>
>> Hi all,
>>
>> In doing my due dillegence on my system, I decided to run the
>> mtd-tests. I'm getting a few failures that I'd like your help in
>> understanding.
>>
>> The one that worries me comes from mtd_oobtest:
>>
>>      # modprobe mtd_oobtest dev=7
>>      mtd_oobtest: error: verify failed at 0x880000
>>      mtd_oobtest: error: verify failed at 0xe80000
>>
>> The most worrysome thing about this is the fact that the result isn't
>> consistant. sometimes I get no failures, and sometimes they're at
>> different spots.
>
> I think this should be related with nand flash's bitflips. As atmel nand
> driver just use standard oob write/read functions from nand_base.c.
> That means there is no ecc protection for mtd_oobtest.
> So if there has any nand bitflip happens in the oob area, then mtd-oobtest
> will be failed.
>
> How often does the failures comes?
> I tested on my at91sam9g25ek board (nand is: 29F2G08AAD) about 20 times, no
> error happened.
>

On our board, it happens more or less every other run.  0x880000 is
most frequent, followed by a few others at random times.

Your other email and this one made me worry about bitflips in the OOB
area, so I decided to test those.  The results are on the other
thread, but the important one here is the checking what happens to a
bit flip on the ECC data.  I did this manually and the ECC code was
able to successfully correct for this problem. I'm calling that good!

Thanks,
- Steve

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2015-01-09  5:06 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2015-01-03  2:34 help with mtd-test failures? Steve deRosier
2015-01-04  8:15 ` Josh Wu
2015-01-09  5:05   ` Steve deRosier

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