On Thursday 28 May 2009, Magnus Damm wrote: > On Wed, May 27, 2009 at 11:30 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, 27 May 2009, Magnus Damm wrote: > >> PM: Runtime platform device power management > > > Have you given any thought as to whether the platform_device_wakeup and > > platform_device_idle calls should be restricted to process context? > > Good question. The first thing that pops into my mind is to have same > restrictions as clk_enable() and clk_disable(). To keep things simple > I'd say that it's unlikely that any embedded platform driver would > need to sleep during the dev_pm_ops callbacks. Maybe it makes sense to > only allow _noirq variants of dev_pm_ops, not sure. Any ideas? > > > You should consider using a special workqueue for this stuff instead of > > relying on the default workqueue. It can help avoid deadlocks, and it > > has the advantage that you can define the workqueue to be freezable. > > (Generally speaking, you don't want platform-level wakeup and idle > > calls to start running spontaneously in the middle of a system sleep > > transition.) > > Yeah, the mockup code needs more work. =) For SuperH Mobile I suspect > that we don't need any workqueues since the freeze() and disabling of > power has to be done from cpuidle context. For SoCs with more complex > power domain layouts it may make sense handle each power domain > independently. And on top of this we probably want to have some QoS > information so the runtime pm code can chose which device sleep mode > to enter. Like cpuidle but for devices or power domains. I think we'll need one separate workqueue for run-time PM in general, so that bus types don't introduce their own workqueues for this purpose. IMO one system-wide run-time PM workqueue should be sufficient (it could also be used for the suspend blockers BTW). So, perhaps it makes sense to implement such a workqueue at the core level? Thoughts? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
