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

[Enric Balletbo i Serra]

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@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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