Rafael: What should happen during system wakeup if a device was runtime-suspended when the sleep began? Although there are circumstances where the device could remain suspended, on the whole it seems a lot safer and easier always to go back to full power. Certainly it's necessary during the RESTORE phase of hibernation, because then the device's physical state is unknown. And even during the RESUME phase of system suspend, the firmware could have made some unwelcome changes to the device. In the THAW phase of hibernation it may not be necessary -- but consider the disk drive that will be used for storing the memory image. If it was runtime-suspended then it will need a runtime-resume, and it will probably have to use an async pm_request_resume() call, but the PM workqueue will be frozen so nothing will happen. Not to mention all the issues involved with remote wakeup. So okay. This should be mentioned in the documentation since it is important, especially for drivers that have different pathways for system resume and runtime resume. This means that when a driver's system-resume routine is finished, the device will be at full power and so dev->power.runtime_status needs to be changed to RPM_ACTIVE. Hence a runtime-PM-aware driver will have to do something like: pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); in its system-resume routine. There probably should be a function in the PM core to encapsulate this. Whether there is or not, drivers must know to do it so it should be mentioned in the documentation. (The PM core can't do it automatically, because it would mess up drivers that aren't runtime-PM-aware.) Also, when the system resume is finished, drivers need a chance to runtime-suspend again. Hence the pm_runtime_put_noidle() call in dpm_complete() should be changed to pm_runtime_put_sync(). Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
