linux-kernel - Re: [PATCH] mmc: core: Wait for command setting 'Power Off Notification' bit to complete

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Date:   Fri, 21 Jan 2022 15:32:20 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Andrey Skvortsov <andrej.skvortzov@...il.com>
Cc:     Arnaud Ferraris <arnaud.ferraris@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Avri Altman <avri.altman@....com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Huijin Park <huijin.park@...sung.com>,
        Christian Löhle <CLoehle@...erstone.com>,
        Yue Hu <huyue2@...ong.com>, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: core: Wait for command setting 'Power Off
 Notification' bit to complete

On Sat, 15 Jan 2022 at 13:15, Andrey Skvortsov
<andrej.skvortzov@...il.com> wrote:
>
> SD card is allowed to signal busy on DAT0 up to 1s after the
> CMD49. According to SD spec (version 6.0 section 5.8.1.3) first host
> waits until busy of CMD49 is released and only then polls Power
> Management Status register up to 1s until the card indicates ready to
> power off.
>
> Without waiting for busy before polling status register sometimes card
> becomes unresponsive and system fails to suspend:
>
>   [  205.907459] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
>   [  206.421274] sunxi-mmc 1c0f000.mmc: data error, sending stop command
>   [  206.421321] sunxi-mmc 1c0f000.mmc: send stop command failed
>   [  206.421347] mmc0: error -110 reading status reg of PM func
>   [  206.421366] PM: dpm_run_callback(): mmc_bus_suspend+0x0/0x74 returns -110
>   [  206.421402] mmcblk mmc0:aaaa: PM: failed to suspend async: error -110
>   [  206.437064] PM: Some devices failed to suspend, or early wake event detected
>
> Tested with Sandisk Extreme PRO A2 64GB on Allwinner A64 system.
>
> Signed-off-by: Andrey Skvortsov <andrej.skvortzov@...il.com>

I did some tests at my side too, using a Qcom platform and it worked
fine. However, I also used the same type of card as you, as I didn't
have any other try with at this moment.

So, applied for fixes and by adding a fixes/stable tag, thanks!

I also did a minor amendment to the patch, see below.

Kind regards
Uffe

> ---
>  drivers/mmc/core/sd.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index e223275bbad1..842b886bdd4e 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -66,7 +66,7 @@ static const unsigned int sd_au_size[] = {
>                 __res & __mask;                                         \
>         })
>
> -#define SD_POWEROFF_NOTIFY_TIMEOUT_MS 2000
> +#define SD_POWEROFF_NOTIFY_TIMEOUT_MS 1000
>  #define SD_WRITE_EXTR_SINGLE_TIMEOUT_MS 1000
>
>  struct sd_busy_data {
> @@ -1663,6 +1663,13 @@ static int sd_poweroff_notify(struct mmc_card *card)
>                 goto out;
>         }
>
> +       /* Find out when the command is completed. */
> +       err = mmc_poll_for_busy(card, SD_POWEROFF_NOTIFY_TIMEOUT_MS, false,

/s/SD_POWEROFF_NOTIFY_TIMEOUT_MS/SD_WRITE_EXTR_SINGLE_TIMEOUT_MS

> +                               MMC_BUSY_EXTR_SINGLE);
> +
> +       if (err)
> +               goto out;
> +
>         cb_data.card = card;
>         cb_data.reg_buf = reg_buf;
>         err = __mmc_poll_for_busy(card->host, SD_POWEROFF_NOTIFY_TIMEOUT_MS,
> --
> 2.34.1
>

Kind regards
Uffe