Testing a device using mtd_stresstest

[Arno Steffen]

I did some same observations. Especially I digged around with the subpage issue.
As options failes, I did patch the nand_base.c to set this bit.
At least test doesn't fail anymore. But this is a far from perfect solution.

With this uncorrectable errors: I struggled with it for month until I
found that there has been some patch (for OMAP).
I assume this is for TI OMAP only, but I don't know, what processor do you use.

There are still some other issues in with jffs2, I reported. It seems
nobody here cares about.
Artem has fixed one of the reported bugs into ubifs, but this doesn't
help me much.
JFFS2 is without support - as far as I could see.

Best regards
Arno

2011/2/7 David Peverley <pev at sketchymonkey.com>:
> Hi Artem,
>
> Many thanks for the response ;
>
>> MTD code is currently broken and CONFIG_MTD_NAND_VERIFY_WRITE causes
>> errors when sub-pages are used. You should either disable this
>> configuration option or fix MTD. We have this in our FAQ:
>>
>> http://www.linux-mtd.infradead.org/faq/ubi.html#L_subpage_verify_fail
> I'm not sure what the implication of this is ; I understand that this
> will cause the subpage test to fail with CONFIG_MTD_NAND_VERIFY_WRITE
> enabled. However, the FAQ I had discounted as we use YAFFS2 and not
> UBIFS. Given that should I still disable the write verify? At the
> moment I'm inclined to leave it enabled as it seems to be regularly
> catching failures that should not occur, such as the stress-test
> failures noted.
>
> We've also noticed that every so often we see "uncorrectable error:"
> messages from nand_ecc.c - do you have any suggestions as to where to
> start investigating here? So far I can't find a pattern to occurrences
> or a regular way to reproduce.
>
> Thanks again!
>
> ~Pev
>
> On 6 February 2011 14:24, Artem Bityutskiy <dedekind1 at gmail.com> wrote:
>> Hi,
>>
>> On Mon, 2011-01-31 at 12:12 +0000, David Peverley wrote:
>>> Question 1 : The  mtd_subpagetest (which I suspect should fail as the
>>> device doesn't support sub-pages). I googled around and found a
>>> reference that maybe I should add NAND_NO_SUBPAGE_WRITE to the
>>> options. I tried this and it made no difference. Out of curiosity I
>>> grepped through drivers/mtd and found that *no* drivers actully use
>>> this bit anyway...! Is it reasonable to ignore this or ought I address
>>> it? Should I set the flag and expect it to have an effect?
>>
>> MTD code is currently broken and CONFIG_MTD_NAND_VERIFY_WRITE causes
>> errors when sub-pages are used. You should either disable this
>> configuration option or fix MTD. We have this in our FAQ:
>>
>> http://www.linux-mtd.infradead.org/faq/ubi.html#L_subpage_verify_fail
>>
>>
>>> Question 2 : The mtd_stresstest test fails after anywhere between 1000
>>> and 200,000 operations. I'm certain this is a Bad Sign. It fails in
>>> nand_base.c:nand_write_page() in the verification step enabled by
>>> MTD_NAND_VERIFY_WRITE. When I tested this on our previous board (that
>>> ostensibly works fine) it failed the stress test after 2.6M operations
>>> instead. Should I be expecting to never see a failure of the stress
>>> test or is an occasional verify failure reasonably expected?
>>
>> Yes, the test is expected to never fail. You should try to dig and
>> understand why is it failing and what is the reason.
>>
>> --
>> Best Regards,
>> Artem Bityutskiy (Артём Битюцкий)
>>
>>
>
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