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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Thu, 23 Sep 2021 20:49:35 +0200
Message-ID: <CAPDyKFqD=KKgSC1PQz_RVm=sGMWtdFsaHSHDiKDxMKajbkszMA@mail.gmail.com>
Subject: Re: [PATCH] mmc: dw_mmc: Dont wait for DRTO on Write RSP error
To:     =?UTF-8?Q?Christian_L=C3=B6hle?= <CLoehle@hyperstone.com>
Cc:     "jh80.chung@samsung.com" <jh80.chung@samsung.com>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Thu, 16 Sept 2021 at 07:59, Christian L=C3=B6hle <CLoehle@hyperstone.com=
> wrote:
>
> Only wait for DRTO on reads, otherwise the driver hangs.
>
> The driver prevents sending CMD12 on response errors like CRCs.
> According to the comment this is because some cards have problems
> with this during the UHS tuning sequence.
> Unfortunately this workaround currently also applies for any command
> with data.
> On reads this will set the drto timer which then triggers after a while.
> On writes this will not set any timer and the tasklet will not be
> scheduled again.
> I cannot attest for the UHS workarounds need, but even if so, it should
> at most apply to reads.
> I have observed many hangs when CMD25 response contained a CRC error.
> This patch fixes this without touching the actual UHS tuning workaround.
>
> Signed-off-by: Christian Loehle <cloehle@hyperstone.com>

Applied for next and by adding a stable tag, thanks!

If you don't think we need the stable tag, please tell me.

Kind regards
Uffe


> ---
>  drivers/mmc/host/dw_mmc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 6578cc64ae9e..22cf13dc799b 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2081,7 +2081,8 @@ static void dw_mci_tasklet_func(struct tasklet_stru=
ct *t)
>                                  * delayed. Allowing the transfer to take=
 place
>                                  * avoids races and keeps things simple.
>                                  */
> -                               if (err !=3D -ETIMEDOUT) {
> +                               if (err !=3D -ETIMEDOUT &&
> +                                   host->dir_status =3D=3D DW_MCI_RECV_S=
TATUS) {
>                                         state =3D STATE_SENDING_DATA;
>                                         continue;
>                                 }
> --
> 2.32.0
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