Re: [PATCH] ASoC: rockchip: rockchip_sai: Hand over hclk control exclusively to Runtime PM

[Bui Duc Phuc]

Hi Nicolas,

Thanks for confirming and for the detailed feedback.

> > Regarding the case where PM configuration is not enabled, with the old
> > source code, I suspect there is an unbalanced clk_disable_unprepare()
> > call on hclk when the driver is unbound after a successful probe under
> > CONFIG_PM=n.
>
> If "old source code" refers to what's currently in the tree with the
> devm_clk_get_enabled, then yes. There's the manual resume function
> call which isn't balanced.
>
> I think your follow-up patch does make sense in light of that.
>

> > I noticed that Nicolas tested and ACKed the use of devm_clk_get_enabled(),
> > so I'm not sure whether that testing included the CONFIG_PM=n configuration.
>
> Nope, I basically never build with PM/RPM disabled.
>

> > > You are right, pm_runtime_get_noresume() doesn't set RPM_ACTIVE. I
> > > think we need to add
> > > pm_runtime_set_active() before pm_runtime_enable(). Otherwise, with CONFIG_PM,
> > > the pm_runtime_put() at the end of probe() might skip the suspend,
> > > since the core still considers
> > > the device suspended .
>
> Agreed, this needs fixing. That is an odd behaviour of the PM API.
>

I'll update the commit message accordingly and include the runtime PM state fix
in the next revision.

Best regards,
Phuc