Re: [PATCH RESEND] i2c/nomadik: runtime PM support

[Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>]

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On Thu, May 03, 2012 at 11:03:12AM +0200, Linus Walleij wrote:
> On Wed, Apr 18, 2012 at 8:39 AM, Magnus Damm <magnus.damm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> > Our drivers assume that the ->runtime_suspend() and ->runtime_resume()
> > callbacks are executed before/after the power is turned off/on for a
> > certain power domain. The way they are used in this patch more seems
> > like they are expected to be called regardless of the state of the
> > rest of the devices sharing the underlying power domain.

...

> On systems where we know the driver is always used with
> power domains the world is easier, but this is not the case
> here. This piece of code in rumtime PM is the source of the
> confusion:

One thing that the regulator framework has which might be useful here is
that it can notify drivers when power is actually removed.  This allows
drivers to reduce the amount of work they need to do to bring the device
back up if they know power was retained while they were suspended.

It feels like some of the confusion is over the difference between
quiescing the device when idle and actually removing power from the
device.

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