"Rafael J. Wysocki" <rjw@xxxxxxx> writes: [..] > If I understand you correctly, you want to have an iterface for specifying > min and max frequencies from user space. I can understand that. At least > I can see some use cases for that. > > Now, the question is if using the PM QoS framework is the right way to do > that. > >> The change to cpufreq core just adds two read-only files to be able to >> inspect user_policy.min/max in addition to the currently enforced >> policy->min/max. Yes - there has been the possibility of using the sysfs >> min for setting a frequency floor but this is problematic when there are >> multiple clients. You'd need some kind of arbitration and book keeping >> to set/restore the minimum. And PM QoS provides exactly this mechanism. > > Just as I suspected. :-) > > OK, so what's your anticipated usage model of this? We've been experimenting with hooking the frequency boost to e.g. touch screen UI events and application launch. I believe there are also some specific applications that would want to either set a frequency floor or ceiling in some situations. >> I think the kernel needs to be extended to handle more PM constraints >> and PM QoS is the closest thing I know for this kind of >> functionality. However, I'm open to suggestions about alternative >> approaches. I think we need e.g. more than just min/max "reduction >> operators". Ideas, anyone? > > I first need to know who those multiple clients are going to be. > > Thanks, > Rafael For the touch screen UI, the boost could be implemented as a kernel module hooked with suitable event filter to the input event stream. Another possibility is the UI framework in user space. Some specific user space applications would also be clients. --Antti _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
