Re: [PATCH v10 1/5] PM / Runtime: Allow accessing irq_safe if no PM_RUNTIME

[Alan Stern]

On Mon, 10 Nov 2014, Ulf Hansson wrote:

> > To me, this sounds like a good reason to avoid using
> > force_runtime_suspend().  In fact, it sounds like a good reason to
> > avoid relying on the runtime PM mechanism to handle non-runtime-PM
> > things (like a system suspend callback).  If CONFIG_PM_RUNTIME isn't
> > enabled then the runtime PM stack simply should not be used.
> 
> There are an important advantage of using the pm_runtime_force_suspend() here.
> 
> For the driver to handle clock gating at system PM suspend, it first
> needs to bring the device into full power, through
> pm_runtime_get_sync(). Otherwise it's not safe to gate the clock,
> since it may already be gated.

That's fine, but it has nothing to do with pm_runtime_force_suspend().

Besides, if the real question is whether or not to gate the clock (or 
in other words, has the clock already been gated), why not just store a 
"clock_is_gated" flag somewhere?

Alan Stern

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