RE: [PATCH] mmc: sleep notification

Alex Lemberg
2015-03-16T11:37:34Z

Hi Ulf,

> -----Original Message-----
> From: Ulf Hansson [mailto:ulf.hansson@linaro.org]
> Sent: Thursday, March 12, 2015 11:10 AM
> To: Alex Lemberg
> Cc: Avi Shchislowski; linux-mmc; Chris Ball
> Subject: Re: [PATCH] mmc: sleep notification
>
> [...]
>
> >> > Also, I think we need to clarify one more point for this patch:
> >> > As was mentioned in commit message - Sleep_Notification can be
> >> > interrupted
> >> by HPI.
> >> > This allows not blocking the host during the Sleep_Notification
> >> > busy time and allows accepting requests coming during this stage.
> >> > Thus, without having HPI supported, suspend/resume process might be
> >> > influenced by Sleep_Notification busy time, and this should not
> >> > happen -
> >> suspend/resume should be done in very fast and not blocking manner.
> >>
> >> I fail to understand your comment here.
> >>
> >> Please tell me at what point(s) your think it make sense to issue the
> >> SLEEP_NOTIFICATION? If that is during the suspend phase, then a HPI
> >> request can't be triggered.
> >
> > I think SLEEP_NOTIFICATION should be issued on mmc_pm_notify() call,
> > on PM_SUSPEND_PREPARE case.
>
> So, exactly why is that to prefer, comparing doing it in system PM
> ->suspend() callback?

Assuming that SLEEP_NOTIFICATION may take time
(defined in SLEEP_NOTIFICATION_TIME byte in EXT_CSD [216]),
I think it is better to send it from pm notifier - mmc_pm_notify().

>
> Kind regards
> Uffe