On Friday, November 19, 2010, Alan Stern wrote: > This patch (as1431b) makes the synchronous runtime-PM interface > suitable for use in interrupt handlers. Subsystems can call the new > pm_runtime_irq_safe() function to tell the PM core that a device's > runtime-PM callbacks should be invoked with interrupts disabled > (runtime_suspend and runtime_resume callbacks will be invoked with the > spinlock held as well). This permits the pm_runtime_get_sync() and > pm_runtime_put_sync() routines to be called from within interrupt > handlers. > > When a device is declared irq-safe in this way, the PM core increments > the parent's usage count, so the parent will never be runtime > suspended. This prevents difficult situations in which an irq-safe > device can't resume because it is forced to wait for its non-irq-safe > parent. > > Signed-off-by: Alan Stern <[email protected]> > > --- > > Index: usb-2.6/include/linux/pm.h > =================================================================== > --- usb-2.6.orig/include/linux/pm.h > +++ usb-2.6/include/linux/pm.h > @@ -486,6 +486,7 @@ struct dev_pm_info { > unsigned int run_wake:1; > unsigned int runtime_auto:1; > unsigned int no_callbacks:1; > + unsigned int irq_safe:1; > unsigned int use_autosuspend:1; > unsigned int timer_autosuspends:1; > enum rpm_request request; > Index: usb-2.6/include/linux/pm_runtime.h > =================================================================== > --- usb-2.6.orig/include/linux/pm_runtime.h > +++ usb-2.6/include/linux/pm_runtime.h > @@ -40,6 +40,7 @@ extern int pm_generic_runtime_idle(struc > extern int pm_generic_runtime_suspend(struct device *dev); > extern int pm_generic_runtime_resume(struct device *dev); > extern void pm_runtime_no_callbacks(struct device *dev); > +extern void pm_runtime_irq_safe(struct device *dev); > extern void __pm_runtime_use_autosuspend(struct device *dev, bool use); > extern void pm_runtime_set_autosuspend_delay(struct device *dev, int delay); > extern unsigned long pm_runtime_autosuspend_expiration(struct device *dev); > @@ -123,6 +124,7 @@ static inline int pm_generic_runtime_idl > static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; > } > static inline int pm_generic_runtime_resume(struct device *dev) { return 0; } > static inline void pm_runtime_no_callbacks(struct device *dev) {} > +static inline void pm_runtime_irq_safe(struct device *dev) {} > > static inline void pm_runtime_mark_last_busy(struct device *dev) {} > static inline void __pm_runtime_use_autosuspend(struct device *dev, > Index: usb-2.6/drivers/base/power/runtime.c > =================================================================== > --- usb-2.6.orig/drivers/base/power/runtime.c > +++ usb-2.6/drivers/base/power/runtime.c > @@ -223,11 +223,19 @@ static int rpm_idle(struct device *dev, > callback = NULL; > > if (callback) { > - spin_unlock_irq(&dev->power.lock); > + if (dev->power.irq_safe) { > + spin_unlock(&dev->power.lock); > > - callback(dev); > + callback(dev); > > - spin_lock_irq(&dev->power.lock); > + spin_lock(&dev->power.lock); > + } else { > + spin_unlock_irq(&dev->power.lock); > + > + callback(dev); > + > + spin_lock_irq(&dev->power.lock); > + } > }
I didn't like this change before and I still don't like it. Quite frankly, I'm not sure I can convince Linus to pull it. :-) Why don't we simply execute the callback under the spinlock in the IRQ safe case? Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
