Re: [PATCH v7 1/5] PM / Runtime: Add getter for quering the IRQ safe option

From: Alan Stern
Date: Wed Sep 24 2014 - 15:47:20 EST

On Wed, 24 Sep 2014, Pavel Machek wrote:

> On Wed 2014-09-24 15:50:08, Krzysztof Kozlowski wrote:
> > Add a simple getter pm_runtime_is_irq_safe() for quering whether runtime
> > PM IRQ safe was set or not.
> >
> > Various bus drivers implementing runtime PM may use choose to suspend
> > differently based on IRQ safeness status of child driver (e.g. do not
> > unprepare the clock if IRQ safe is not set).
> >
> > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> > Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Are you sure this is good interface?
> "Tell me if another function works this or that way".
> That's certainly not traditional interface, and it seems dangerous to
> me. Callbacks now have different semantic requirements based on value
> of some flag...
> Would it be possible to have two sets of callbacks, one irq safe and
> one not?

Or maybe add a flag to the bus-specific device structures, indicating
specifically whether or not the clock should be unprepared during a
runtime suspend. Then individual drivers could set this flag or not,
independent of the irq-safe setting.

Alan Stern

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