Messages in this thread | | | Subject | Re: [PATCH 3/3] PM: domains: Add a ->dev_get_performance_state() callback to genpd | From | Dmitry Osipenko <> | Date | Fri, 10 Sep 2021 14:24:38 +0300 |
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09.09.2021 17:39, Ulf Hansson пишет: > On Thu, 9 Sept 2021 at 15:48, Dmitry Osipenko <digetx@gmail.com> wrote: >> >> 07.09.2021 12:57, Ulf Hansson пишет: >>> I don't mind extending the genpd API, but it needs to serve a good purpose. >>> >>> As I said earlier, genpd doesn't know nor can control how the consumer >>> driver deploys runtime PM. Unfortunately, that also includes genpd >>> providers, as the behavior isn't a platform or PM domain specific >>> thing. This means genpd needs to be generic enough so it works for all >>> cases. >>> >>> In the $subject patch, we rely on the pm_runtime_suspended() check in >>> dev_pm_genpd_set_performance_state(), which should work for all cases, >>> even if it may be sub-optimal for some scenarios. >>> >>> Note that, in the approach your suggested [1], >>> pm_runtime_status_suspended() is used instead. This doesn't work when >>> a consumer driver doesn't enable runtime PM - or calls >>> pm_runtime_set_active() during ->probe(), because >>> genpd_runtime_resume() won't be invoked to restore the gpd->rpm_state. >>> >>> That said, I wouldn't mind to simply skip adding the >>> ->dev_get_performance_state() all together, if that is what you >>> prefer? In this way, it becomes the responsibility for the consumer >>> driver to do right thing, with the cost of some boilerplate code added >>> in its ->probe() routine. >> >> Until a day ago, it wasn't clear to me that consumer drivers now can set >> up rpm_pstate during probe(), which is a cleaner solution that works >> well. So let's skip adding the questionable ->dev_get_performance_state(). >> >> The boilerplate code in the probe() is minimal in comparison to a >> previous variant with the state-syncing done by rpm-resume callbacks of >> consumer drivers, it's good enough. > > Alright, that sounds good to me as well. > > I am happy to help with review of the consumer driver changes, just > keep me posted.
Thank you and Viresh for the help, very appreciate it!
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