Re: [PATCH v2 7/7] USB / PM: Allow USB devices to remain runtime-suspended when sleeping

From: Rafael J. Wysocki
Date: Fri Apr 03 2015 - 16:59:31 EST


On Friday, April 03, 2015 01:44:36 PM Dmitry Torokhov wrote:
> Hi Tomeu,
>
> On Fri, Apr 03, 2015 at 02:57:56PM +0200, Tomeu Vizoso wrote:
> > Have dev_pm_ops.prepare return 1 for USB devices, interfaces, endpoints
> > and ports so that USB devices can remain runtime-suspended when the
> > system goes to a sleep state, if their wakeup state is correct.
> >
> > Also enable runtime PM for endpoints, which is another requirement for
> > the above to work.
>
> After patching I think the 4th unrelated subsystem with stubs for
> prepare() I think it is pretty clear that this approach is not the right
> one.
>
> If your driver does not care about any children hanging off it there is
> dev->ignore_children flag that either already does what you want, or
> maybe needs adjusted to support your use case.

I wouldn't overload ignore_children with that meaning. That said adding
a "return 1 from device_prepare() if this is set" flag might be a good idea.


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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