Hi Ulf,
> > > > +static bool mmc_may_poweroff_notify(const struct mmc_host *host,
> > > > + bool is_suspend)
> >
> > Maybe add some comments about the difference between
> > mmc_can_poweroff_notify() and mmc_may_poweroff_notify()? Like make it
> > super-obvious, so I will easily remember next year again :)
>
> mmc_can_* functions are mostly about checking what the card is capable
> of. So mmc_can_poweroff_notify() should be consistent with the other
> similar functions.
>
> For eMMC power-off notifications in particular, it has become more
> complicated as we need to check the power-off scenario along with the
> host's capabilities, to understand what we should do.
>
> I am certainly open to another name than mmc_may_power_off_notify(),
> if that is what you are suggesting. Do you have a proposal? :-)
Initially, I didn't think of new names but some explanation in comments.
But since you are mentioning a rename now, how about:
mmc_card_can_poweroff_notify() and mmc_host_can_poweroff_notify()?
Similar to the commit 32f18e596141 ("mmc: improve API to make clear
hw_reset callback is for cards") where I renamed 'hw_reset' to
'card_hw_reset' for AFAICS similar reasons.
> > > > if (mmc_can_poweroff_notify(host->card) &&
> > > > - !(host->caps2 & MMC_CAP2_FULL_PWR_CYCLE))
> > > > + !mmc_may_poweroff_notify(host, true))
> > > I guess this deserve some extra documentation because:
> > > If MMC_CAP2_FULL_PWR_CYCLE is not set but MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND is set,
> > > !mmc_may_poweroff_notify(host, true) will evaluate to false while !(host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) will evaluate to true.
>
> Right. See more below.
>
> >
> > I agree, I neither get this. Another way to express my confusion is: Why
> > do we set the 'is_suspend' flag to true in the shutdown function?
> >
>
> I understand your concern and I agree that this is rather messy.
> Anyway, for shutdown, we set the is_suspend flag to false. The
> reasoning behind this is that during shutdown we know that the card
> will be fully powered-down (both vcc and vccq will be cut).
>
> In suspend/runtime_suspend, we don't really know as it depends on what
> the platform/host is capable of. If we can't do a full power-off
> (maybe just vcc can be cut), then we prefer the sleep command instead.
I do understand that. I don't see why this needs a change in the
existing logic as Alan pointed out above.
> I was hoping that patch3 should make this more clear (using an enum
Sadly, it didn't. Using MMC_POWEROFF_SUSPEND first and then later
MMC_POWEROFF_SHUTDOWN in mmc_shutdown() is still confusing. Do you want
to return false in case none of the two PWR_CYCLE flags is set?
> type), but I can try to add some comment(s) in the code to further
> clarify the policy.
Please do.
All the best,
Wolfram
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