Re: [PATCH v13 06/35] clk: tegra: Support runtime PM and power domain

[Dmitry Osipenko]

06.10.2021 15:38, Ulf Hansson пишет:
>> I'm also wondering if we could add some 'was_enabled' flag to GENPDs,
>> setting it by genpd_suspend_noirq() for the enabled domains, and then
>> powering-on GENPDs from genpd_resume_noirq() only if they were in the
>> enabled state during genpd_suspend_noirq() time. It actually puzzled me
>> for a quite long time why GENPD core enables domains unconditionally
>> during early resume. This should solve a part of the problem and it
>> makes suspend/resume a bit safer because there is a smaller chance to
>> crash hardware during suspend, at least it's easier to debug.
> Just because the PM domain was already off at genpd_suspend_noirq(),
> doesn't mean that it can stay powered off at genpd_resume_noirq(). At
> least as is today.
> 
> The main reason why genpd_resume_noirq() powers on the PM domain, is
> because it's not possible for the consumer drivers to rely on runtime
> PM to do it (because runtime PM has been disabled by the PM core).

At least Tegra doesn't need to have domains force-resumed. This should
be a platform-specific behaviour. We may add a new flag for that, I
suppose. I'll try to keep this in mind for a future improvement. Thank
you for the clarification.