linux-kernel - Re: [PATCH v2 2/5] mmc: core: Further avoid re-storing power to the eMMC before a shutdown

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Message-ID: <CAPDyKFoOfNWa6b0jF0-a-imKqdDJQrdJe65OaOj3D0upmS7VXw@mail.gmail.com>
Date: Tue, 8 Apr 2025 14:40:29 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>, Ulf Hansson <ulf.hansson@...aro.org>, 
	linux-mmc@...r.kernel.org, Adrian Hunter <adrian.hunter@...el.com>, 
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>, Avri Altman <Avri.Altman@...disk.com>, 
	linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/5] mmc: core: Further avoid re-storing power to the
 eMMC before a shutdown

On Tue, 8 Apr 2025 at 10:09, Wolfram Sang
<wsa+renesas@...g-engineering.com> wrote:
>
>
> > @@ -2187,11 +2198,12 @@ static int mmc_shutdown(struct mmc_host *host)
> >       int err = 0;
> >
> >       /*
> > -      * In a specific case for poweroff notify, we need to resume the card
> > -      * before we can shutdown it properly.
> > +      * If the card remains suspended at this point and it was done by using
> > +      * the sleep-cmd (CMD5), we may need to re-initialize it first, to allow
> > +      * us to send the preferred poweroff-notification cmd at shutdown.
> >        */
> >       if (mmc_can_poweroff_notify(host->card) &&
> > -             !(host->caps2 & MMC_CAP2_FULL_PWR_CYCLE))
> > +         !mmc_host_can_poweroff_notify(host, true))
>
> Ooookay, I think I got this logic now. I think it makes sense to make it
> more explicit in the comment, though:
>
> "This is then the case when the card is able to handle poweroff
> notifications in general but the host could not initiate those for
> suspend."
>
> Something like this?

Well, in my opinion I think this would become a bit too much comments
in the code.

The rather long function-names "mmc_can_poweroff_notify" (that will
change to mmc_card_can_poweroff_notify with your series) and
"mmc_host_can_poweroff_notify" are rather self-explanatory, don't you
think?

Kind regards
Uffe