Saugata Das wrote:
> On 14 December 2011 10:04, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote:
> > Saugata Das wrote:
> >> On 13 December 2011 11:57, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote:
> >> > Hi Saugata,
> >> >
> >> > Saugata Das wrote:
> >> >> Hi Seungwon Jeon
> >> >>
> >> >> I see a small issue with the implementation mmc_suspend_host,
> >> >>
> >> >> int mmc_suspend_host(struct mmc_host *host)
> >> >> {
> >> >> .....
> >> >> err = mmc_cache_ctrl(host, 0);
> >> >> }
> >> >>
> >> >> So, within mmc_suspend_host we are disabling the cache. But I do not
> >> >> see a corresponding enabling of cache within mmc_resume_host. I
> >> >> suggest we have either enabling of cache within mmc_resume_host or
> >> >> within mmc_suspend_host, we replace mmc_cache_ctrl(host, 0) with the
> >> >> flush operation, mmc_flush_cache(host->card).
> >> >>
> >> > Currently,
> >> > Cache is enabled in mmc_init_card() during mmc_resume_host().
> >> >
> >> Thanks for your answer.
> >>
> >> If mmc_card_keep_power is TRUE, then do you know why from mmc_resume
> >> we call mmc_init_card instead of just mmc_awake which should reduce
> >> some latency of system wakeup ?
> >>
> > I didn't find that case of keeping the power
> > during sleep in mmc unlike sdio.
>
> I am talking about keeping VCCQ ON and switching OFF only VCC. This is
> normally the SLEEP mode of eMMC, which provides quicker wakeup or
> resume. Some platforms will like to have quicker resume and will like
> to avoid doing a mmc_init_card during resume. If that happens, then
> the cache control disabling from mmc_suspend_host will be a problem.
> So, I suggest we change that to mmc_flush_cache which logically does
> the same as you wanted but it is also future proof.
Yes.
Currently mmc can wake up from sleep state using only CMD0 in mmc_init_card.
If we separate the escape route from sleep state, it must be considered.
Thank you for suggestion.
>
> >
> >>
> >> > Thanks,
> >> > Seungwon Jeon.
> >> >>
> >> >>
> >> >> Regards
> >> >> Saugata
> >> >> --
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