On Saturday, August 07, 2010, Rafael J. Wysocki wrote: > On Saturday, August 07, 2010, Ted Ts'o wrote: > > On Fri, Aug 06, 2010 at 08:14:09PM -0700, david@xxxxxxx wrote: > > > > > > that description sounds far more like normal sleep power management > > > that suspending. especially since they want to set timers to wake > > > the system up and the defining characteristic of suspend (according > > > to this thread) is that timers don't fire while suspended. > > > > > > as I am seeing it, there are two reasons why this don't "just work" > > > > > > 1. sleeping can't currently save as much power as suspending > > > > No, I don't think that's the case at all. The key thing here is that > > *most* applications don't need to be modified to use suspend locks, > > because even though they might be in an event loop, when the user user > > turns off the display, the user generally doesn't want it doing things > > on their behalf. > > > > Again, take for example the Mac Book, since Apple has gotten this > > right for most users' use cases. When you close the lid, you even if > > the application is under the misguided belief that it should be > > checking every five seconds to see whether or not the web page has > > reloaded --- actually, that's not what you want. You probably want > > the application to be forcibly put to sleep. So the whole point of > > the suspend blocker design is that you don't have to modify most > > applications; they just simply get put to sleep when you close the > > MacBook lid, or, in the case of the Android device, you push the > > button that turns off the screen. > > But in principle that need not mean suspending the entire system. > To get applications out of the way, you need to freeze user space. > However, that's not sufficient, because in addition to that you need to > prevent deactivate the majority of interrupt sources to avoid waking up the > CPU (from C-states) too often. s/prevent deactivate/deactivate/ Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
