Messages in this thread | | | From | Ulf Hansson <> | Date | Thu, 9 Sep 2021 16:39:54 +0200 | Subject | Re: [PATCH 3/3] PM: domains: Add a ->dev_get_performance_state() callback to genpd |
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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.
Thanks and kind regards Uffe
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