On Mon, 11 Apr 2011, Sylwester Nawrocki wrote: > > + void pm_runtime_irq_safe(struct device *dev); > > + - set the power.irq_safe flag for the device, causing the runtime-PM > > + callbacks to be invoked with interrupts disabled > > + > > void pm_runtime_mark_last_busy(struct device *dev); > > - set the power.last_busy field to the current time > > > > @@ -438,6 +454,16 @@ pm_runtime_suspended() > > pm_runtime_mark_last_busy() > > pm_runtime_autosuspend_expiration() > > > > +If pm_runtime_irq_safe() has been called for a device then the following helper > > +functions may also be called in interrupt context: > > I was wondering what is the proper usage of this API. From a point of view of > a driver, does it mean that in runtime_resume/runtime_suspend helpers any > blocking calls cannot be used, so the device driver is prepared for situations > when some other subsystem invokes pm_runtime_irq_safe() on its device? I should have mentioned this in the documentation. Yes, if pm_runtime_irq_safe() has been called for a device then that device's runtime_resume and runtime_suspend helpers must be able to run in interrupt context. Hence they must not make any blocking calls. However, this doesn't mean _all_ runtime_resume/runtime_suspend methods have to be IRQ-safe. Only those for which pm_runtime_irq_safe() has been called. A driver shouldn't worry about some other subsystem calling pm_runtime_irq_safe() for one of its devices. If that ever happened, it would be a gross violation of proper layering. > Or is pm_runtime_irq_safe() intended to be called only by the device driver > in such case? Yes, that's right. > I'd like to use blocking calls for a voltage regulator control within > the runtime PM helpers in the driver but I'm not sure whether this wouldn't > violate the API. You should be okay. Just bear in mind that it means the voltage regulator's parent won't be able to runtime suspend. If the regulator is a platform device with no meaningful parent then of course this won't matter. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
