On Mon, 16 Jun 2025 at 12:29, Oleksij Rempel <o.rempel@pengutronix.de> wrote:
>
> Introduce MMC_POWEROFF_UNDERVOLTAGE as a new mmc_poweroff_type value and
> adjust _mmc_suspend() to skip cache flush for this case. This prepares for
> undervoltage handling in a follow-up patch.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
> changes v5:
> - rebase against latest mmc/next
> - use MMC_POWEROFF_UNDERVOLTAGE enum instead of function parameter.
> changes v3:
> - add comments
> - make sure _mmc_flush_cache is not executed in the undervoltage case
> ---
> drivers/mmc/core/mmc.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 5689ab6eefe1..6812df679ba9 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -36,6 +36,7 @@
> enum mmc_poweroff_type {
> MMC_POWEROFF_SUSPEND,
> MMC_POWEROFF_SHUTDOWN,
> + MMC_POWEROFF_UNDERVOLTAGE,
> MMC_POWEROFF_UNBIND,
> };
>
> @@ -2132,9 +2133,15 @@ static int _mmc_suspend(struct mmc_host *host, enum mmc_poweroff_type pm_type)
> if (mmc_card_suspended(host->card))
> goto out;
>
> - err = _mmc_flush_cache(host);
> - if (err)
> - goto out;
> + /*
> + * For the undervoltage case, we care more about device integrity.
> + * Avoid cache flush and notify the device to power off quickly.
> + */
> + if (pm_type != MMC_POWEROFF_UNDERVOLTAGE) {
> + err = _mmc_flush_cache(host);
> + if (err)
> + goto out;
> + }
I think this sounds reasonable as we may simply not have the time to
complete a flush.
Yet, it may be device specific on what makes best sense. Let's see if
Avri also agrees with this.
>
> if (mmc_card_can_poweroff_notify(host->card) &&
> mmc_host_can_poweroff_notify(host, pm_type))
> --
> 2.39.5
>
That said, please squash this with patch3. Especially since I think
patch3 can be made a bit simpler due to my comments on patch1.
Kind regards
Uffe