Re: [PATCH v2] mmc: dw_mmc: Fix UHS tuning on some brand of cards.

[Jaehoon Chung]

Hi Enric,

On 04/26/2016 12:29 AM, Enric Balletbo Serra wrote:
> Oh, damn, I didn't include the proper tags,
> 
> [PATCH v2] mmc: dw_mmc: Wait for data transfer after response errors.
> [PATCH v2] mmc: dw_mmc: Fix UHS tuning on some brand of cards
> 
> should be
> 
> [PATCH v2 0/1] mmc: dw_mmc: Fix UHS tuning on some brand of cards
> [PATCH v2 1/1] mmc: dw_mmc: Wait for data transfer after response errors.

What changed from patch V1?
Anyway, thanks for reminding! :)

Best Regards,
Jaehoon Chung

> 
> 2016-04-25 17:18 GMT+02:00 Enric Balletbo i Serra
> <enric.balletbo@xxxxxxxxxxxxx>:
>> Hi,
>>
>> I introduced the cover letter to give some background about this.
>>
>> I have been investigating a problem related to at least one specific sdcard when
>> UHS-I is set. The card is not detected due the tuning phase reports a
>> failure. Since the problem is only reproduced with a single model of a single
>> brand of card, it is probably a card firmware issue, but the card works fine
>> on my laptop.
>>
>> The first attempt to fix this was a patch sent by Doug Anderson [1], but Alim
>> Akhtar found that this produced randomly a hung task on Peach-pi. I can confirm
>> that it's easy to reproduce the hung task, either, with cold boots or suspend to
>> ram tests.
>>
>> I tried to fix both problems (the original issue and the one introduced by the
>> patch) in different ways, but I ended thinking that this second proposal is the
>> most simple that solves both issues. So let's try to fix this by handling the
>> response CRC error slightly differently when tuning command is happening.
>>
>> I tested the patch on both platforms, on exynos and on rockhip. I did lots of
>> tests and at the moment the patch seems to fix the rockchip issue and don't
>> hung on exynos. I'll continue testing meanwhile we discuss about it.
>>
>> I think the patch, at least, needs the Doug's approval (as he dig into the issue
>> before) and the Tested-by Alim. So will be good if you have a slot of time to
>> look a bit into this.
>>
>> Thanks in advance.
>>  Enric
>>
>> [1] https://lkml.org/lkml/2015/5/18/495
>>
>> Doug Anderson (1):
>>   mmc: dw_mmc: Wait for data transfer after response errors.
>>
>>  drivers/mmc/host/dw_mmc.c | 27 +++++++++++++++++++++++++++
>>  1 file changed, 27 insertions(+)
>>
>> --
>> 2.1.0
>>
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