On 13/07/17 13:40, Sudeep Holla wrote: > > > On 11/07/17 16:21, Dietmar Eggemann wrote: >> On 11/07/17 07:39, Viresh Kumar wrote: >>> On 10-07-17, 14:46, Rafael J. Wysocki wrote:
[...] >> Like I said in the other email, since for (future) >> arm/arm64 fast-switch driver, the return value of >> cpufreq_driver->fast_switch() does not give us the information that the >> frequency value did actually change, we have to implement > > I was under the impression that we strictly don't care about that > information when I started exploring the fast_switch with the standard > firmware interface on ARM platforms(until if and when ARM provides an > instruction to achieve that). > > If f/w failed to change the frequency, will that be not corrected in the > next sample or instance. I would like to know the impact of absence of > such notifications. In the meantime we agreed that we have to invoke frequency invariance from within the cpufreq driver. For a fast-switch driver I would have to put the call to arch_set_freq_scale() somewhere where I know that the frequency has been set. Without a notification (from the firmware) that the frequency has been set, I would have to call arch_set_freq_scale() somewhere in the driver::fast_switch() call assuming that the frequency has been actually set. [...]