On Thu, 3 Jun 2021 at 21:08, Dmitry Osipenko [off-list ref] wrote:

03.06.2021 22:02, Dmitry Osipenko пишет:

quoted

03.06.2021 12:34, Ulf Hansson пишет:

quoted

A subsystem/driver that need to manage OPPs for its device, should
typically drop its vote for the OPP when the device becomes runtime
suspended. In this way, the corresponding aggregation of the performance
state votes that is managed in genpd for the attached PM domain, may find
that the aggregated vote can be decreased. Hence, it may allow genpd to set
the lower performance state for the PM domain, thus avoiding to waste
energy.

To accomplish this, typically a subsystem/driver would need to call
dev_pm_opp_set_rate|opp() for its device from its ->runtime_suspend()
callback, to drop the vote for the OPP. Accordingly, it needs another call
to dev_pm_opp_set_rate|opp() to restore the vote for the OPP from its
->runtime_resume() callback.

To avoid boilerplate code in subsystems/driver to deal with these things,
let's instead manage this internally in genpd.

Signed-off-by: Ulf Hansson <redacted>
---

Changes in v2:
     - Rebased.
     - A few minor cosmetic changes.
     - Deal with the error path in genpd_runtime_resume().

I tested this on NVIDIA Tegra by removing the boilerplate code from
drivers' RPM and haven't noticed any problems, the performance state is
dropped/restored as expected. Thank you.

Tested-by: Dmitry Osipenko <digetx@gmail.com>

Thanks a lot, much appreciated!

Kind regards
Uffe