Re: [RESEND PATCH v2 0/1] mmc: dw_mmc: Fix UHS tuning on some brand of cards.

[Enric Balletbo Serra]

Hi Jaehoon,

2016-04-27 10:53 GMT+02:00 Enric Balletbo i Serra
<enric.balletbo@xxxxxxxxxxxxx>:
>
>
> On 27/04/16 10:35, Jaehoon Chung wrote:
>> On 04/26/2016 05:03 PM, Enric Balletbo i Serra wrote:
>>> 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.
>>
>> I think you have analyzed many case..of course..it was successful to switch voltage, right?
>> Maybe this patch too old..so can you remember which specific sdcard is produced?
>>
>
> Yes it was successful to switch voltage. The specific card is an UNIREX 16GB Class 10
> SD card (Compatible with UHS-1)
>

Any feedback for this patch?


>>>
>>> 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.
>>
>> Yep..I have already tested and checked for this.
>>
>>>
>>> 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
>>>
>>> Changelog since v1:
>>> - Fix the issue found by Alim with exynos letting the data transfer
>>>   take place only when MMC_SEND_TUNING_BLOCK is issued.
>>>
>>> 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(+)
>>>
>>