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SubjectRe: [PATCH] mmc: dw_mmc: Fix occasional hang after tuning on eMMC
On Mon, 8 Jul 2019 at 21:56, Douglas Anderson <dianders@chromium.org> wrote:
>
> In commit 46d179525a1f ("mmc: dw_mmc: Wait for data transfer after
> response errors.") we fixed a tuning-induced hang that I saw when
> stress testing tuning on certain SD cards. I won't re-hash that whole
> commit, but the summary is that as a normal part of tuning you need to
> deal with transfer errors and there were cases where these transfer
> errors was putting my system into a bad state causing all future
> transfers to fail. That commit fixed handling of the transfer errors
> for me.
>
> In downstream Chrome OS my fix landed and had the same behavior for
> all SD/MMC commands. However, it looks like when the commit landed
> upstream we limited it to only SD tuning commands. Presumably this
> was to try to get around problems that Alim Akhtar reported on exynos
> [1].
>
> Unfortunately while stress testing reboots (and suspend/resume) on
> some rk3288-based Chromebooks I found the same problem on the eMMC on
> some of my Chromebooks (the ones with Hynix eMMC). Since the eMMC
> tuning command is different (MMC_SEND_TUNING_BLOCK_HS200
> vs. MMC_SEND_TUNING_BLOCK) we were basically getting back into the
> same situation.
>
> I'm hoping that whatever problems exynos was having in the past are
> somehow magically fixed now and we can make the behavior the same for
> all commands.
>
> [1] https://lkml.kernel.org/r/CAGOxZ53WfNbaMe0_AM0qBqU47kAfgmPBVZC8K8Y-_J3mDMqW4A@mail.gmail.com
>
> Fixes: 46d179525a1f ("mmc: dw_mmc: Wait for data transfer after response errors.")
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Cc: Alim Akhtar <alim.akhtar@gmail.com>
> Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>

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

Kind regards
Uffe


> ---
> Marek (or anyone else using exynos): is it easy for you to test this
> and check if things are still broken when we land this patch? If so,
> I guess we could have a quirk to have different behavior for just
> Rockchip SoCs but I'd rather avoid that if possible.
>
> NOTE: I'm not hoping totally in vain here. It is possible that some
> of the CTO/DTO timers that landed could be the magic that would get
> exynos unstuck.
>
> drivers/mmc/host/dw_mmc.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index b53b6b7d4dd4..60c3a06e3469 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2034,8 +2034,7 @@ static void dw_mci_tasklet_func(unsigned long priv)
> * delayed. Allowing the transfer to take place
> * avoids races and keeps things simple.
> */
> - if ((err != -ETIMEDOUT) &&
> - (cmd->opcode == MMC_SEND_TUNING_BLOCK)) {
> + if (err != -ETIMEDOUT) {
> state = STATE_SENDING_DATA;
> continue;
> }
> --
> 2.22.0.410.gd8fdbe21b5-goog
>

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