On Tuesday, November 26, 2013 10:48:56 AM Ulf Hansson wrote: > On 26 November 2013 00:10, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > > On Monday, November 25, 2013 01:40:21 PM Ulf Hansson wrote: > >> To put devices into low power state during sleep, it sometimes makes > >> sense at subsystem-level to re-use device's runtime PM callbacks. > >> > >> The PM core will at device_suspend_late disable runtime PM, after that > >> we can safely operate on these callbacks. At suspend_late the device > >> will be put into low power state by invoking the device's > >> runtime_suspend callback, unless the runtime status is already > >> suspended. At resume_early the state is restored by invoking the > >> device's runtime_resume callback. Soon after the PM core will re-enable > >> runtime PM before returning from device_resume_early. > >> > >> The new pm_generic functions are named pm_generic_suspend_late_runtime > >> and pm_generic_resume_early_runtime, they are supposed to be used in > >> pairs. > > > > What happens if the subsystem uses the new functions as its late suspend/ > > early resume callbacks, but some of its drivers implement .suspend_late() > > and .resume_early()? > > Good point. Normally, I think the decision of using these callbacks > should be taken at the lowest level, in other words in the driver. > Otherwise the lowest layer of .suspend_late will be by-passed. I'm not sure what's the point to add them, then. If the driver has to decide anyway, it may simply populate its .suspend_late and .resume_early pointers I think. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
