On 3/25/2017 7:32 AM, Rafael J. Wysocki wrote: > 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! I will remove the caching of CPPC perf caps and submit a patch to add the sysfs entries with existing interface. -- Thanks, Prashanth -- 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
