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

[Enric Balletbo i Serra <enric.balletbo@collabora.com>]

Hi Jaehoon,

On 26/04/16 09:44, Jaehoon Chung wrote:
> 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! :)
>

Argh! also the changelog didn't go with the email. Ok, so let me resend 
this version with the proper tags and proper Changelog. I think will be 
more easy to follow the discussion then. Ignore these and sorry for the 
noise.

Best regards,
Enric

> Best Regards,
> Jaehoon Chung
>
>>
>> 2016-04-25 17:18 GMT+02:00 Enric Balletbo i Serra
>> <enric.balletbo@collabora.com>:
>>> 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
>>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>