On Sun, 12 Jun 2011, Rafael J. Wysocki wrote: > > Basically, I think what Rafael was saying before referred to the > > general case, where you don't know anything about the subsystem and > > can't afford to make assumptions. But in the real world you'll be > > writing a driver for a particular subsystem and you'll know how that > > subsystem works. If the subsystem permits runtime PM calls to be > > nested within the system PM routines, feel free to go ahead and use > > them. > > But then we get the problem that user space may echo "on" to the > device's "control" file in sysfs and the whole clever plan basically goes > south. That would indeed be a problem if we used pm_runtime_suspend() in the system suspend code. But it doesn't prevent us from calling pm_runtime_resume() during system suspend. > Moreover, on some systems devices will belong to PM domains and their > drivers may potentially be used with different PM domains on different > platforms. This means that drivers really should not make any assumptions > about whether or not they can use runtime PM in their system suspend/resume > routines. They can't. Yes, clearly one mustn't make assumptions about unknown subsystems or PM domains. Alan Stern _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
