On Mon, 22 Jun 2009, Rafael J. Wysocki wrote: > On Monday 22 June 2009, Alan Stern wrote: > > On Sun, 21 Jun 2009, Rafael J. Wysocki wrote: > > > > > > Seriously, there _are_ places where drivers get bound to device before > > > > those devices are registered. This happens for example in USB when a > > > > bunch of related interfaces are present in the same physical device. > > > > When the first interface is registered, its driver binds itself to all > > > > the others even though they haven't been registered yet. > > > > > > Well, the suspend functions could be protected against that under the > > > assumption that no suspend is possible for resume_counter = 0 (then, the "good > > > to go" value would be -1). > > > > > > Still, the resume functions start from acquring a spinlock, which is not going > > > to work if that spinlock is uninitialized. > > > > The initialization needs to be improved. Most of the code in > > pm_runtime_init() should be called from device_pm_init(), and the rest > > should be moved into a separate pm_runtime_add() routine to be called > > from device_pm_add(). > > OK > > In that case, I think, the initialization of the spinlock and resume_counter > can be put into the thing called by device_pm_init(). Right. > > One of the things pm_runtime_add() could do is change the status from > > RPM_UNREGISTERED to RPM_ACTIVE. > > If the status is initially (ie. at the device_pm_init() point) RPM_ACTIVE and > resume_couter is initially 1, what are we going to need RPM_UNREGISTERED for? Okay, we don't need it then. I forgot to mention in the previous message that there also has to be a pm_runtime_del() routine, which should cancel pending workqueue items and set the counter to some high value so that no new items are added. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
