On Friday, March 24, 2017 10:34:42 AM Prakash, Prashanth wrote: > > On 3/3/2017 11:32 AM, Prakash, Prashanth wrote: > > Hi Rafael, > > > > On 2/13/2017 9:38 AM, Prakash, Prashanth wrote: > > [...] > >>>> Tested-by: Al Stone <ahs3@xxxxxxxxxx> > >>> I'm not actually sure about the assumption this series is based on. > >>> > >>> I don't see anything in the spec to guarantee that it will always be > >>> safe to evaluate _CPC only once and cache its output. > >> Among the Performance capabilities registers(section 8.4.7.1.1), the only > >> register that can change dynamically is Guaranteed performance register. > >> We are not supporting/using Guaranteed performance at the moment. > >> > >> Guaranteed performance Register has an associated Notify event which will be > >> invoked when it changes. No such events are associated with other capabilities > >> register. Similar distinction is made in the beginning of section 8.4.7.1.1: > >> "Figure 8-47 outlines the static performance thresholds of the platform > >> and the dynamic guaranteed performance threshold." > >> > >> I agree spec isn't very clear about marking these registers as static except > >> that one sentence I quoted above, but there is enough in spec to guarantee > >> that the capabilities we are using will not change dynamically. > > Does the above sound reasonable? Any other feedback on this patch set? > > Gentle Ping There are concerns that some CPPC parameters may change at run time on some systems even though the spec doesn't mention that possibility, so the optimization here may be premature. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
