* Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> [150308 08:41]: > On Fri, 6 Mar 2015, Tony Lindgren wrote: > > > > > I'll verify again, but I believe the issue was that without doing > > > > mark_last_busy here the device falls back asleep right away. > > As it should. If you don't increment the usage counter (for example, > by calling pm_runtime_get instead of pm_request_resume) and you don't > update last_busy then you are telling the PM core that the device > currently isn't busy and it hasn't been in use since the last time it > was suspended. Under those circumstances, the PM core is _supposed_ to > suspend the device right away. OK so it's a feature then. > > > > That probably should be fixed in pm_runtime in general if that's > > > > the case. > > > > > > It's up to the subsystem to handle this. For example, the USB > > > subsystem's runtime-resume routine calls pm_runtime_mark_last_busy. > > > > Hmm.. OK thanks this probably explains why pm_request_resume() did > > not work. > > > > For omaps, I could call this from the interconnect related code, > > but then how dow we deal with the subsystems that don't call it? > > Start by determining _why_ they don't call it. Maybe they have a good > reason. If they don't then fix them. Yes I'll check, it's just probably because the drivers have been calling it instead. > > > > Considering the above, should we add a new function something like > > > > pm_resume_complete() that does not need irq_safe set but does > > > > not return until the device has completed resume? > > > > > > That doesn't make sense. You're asking for a routine that is allowed > > > to sleep but can safely be called in interrupt context. > > > > Oh it naturally would not work in irq context, it's for the bottom > > half again. > > In other words, you're suggesting we add a function that runs in > process context and doesn't return until the device is fully resumed? > That's exactly what pm_runtime_resume does right now. But doesn't it only wait for completion if the driver is marked with pm_runtime_irq_safe()? > > But I'll take a look if we can just call > > pm_request_resume() and disable_irq() on the wakeirq in without > > waiting for the device driver runtime_suspend to disable the wakeirq. > > That would minimize the interface to just dev_pm_request_wakeirq() > > and dev_pm_free_wakeirq(). > > Will that be acceptable in systems with shared IRQ lines? Not without us keeping track of when the wakeirq is enabled or disabled :) Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
