Re: [PATCH v8 01/34] opp: Add dev_pm_opp_sync() helper

Viresh Kumar
2021-08-18T06:27:36Z

On 18-08-21, 09:22, Dmitry Osipenko wrote:
> 18.08.2021 08:58, Viresh Kumar пишет:
> > What about calling dev_pm_opp_set_rate(dev, clk_get_rate(dev)) here
> > instead ? That will work, right ? The advantage is it works without
> > any special routine to do so.
>
> It will work, but a dedicated helper is nicer.
>
> > I also wonder looking at your gr3d.c changes, you set a set-opp
> > helper, but the driver doesn't call set_opp_rate at all. Who calls it
> > ?
>
> dev_pm_opp_sync() calls it from _set_opp().

Okay, please use dev_pm_opp_set_rate() instead then. New helper just
adds to the confusion and isn't doing anything special apart from
doing clk_get_rate() for you.

> > And if it is all about just syncing the genpd core, then can the genpd
> > core do something like what clk framework does? i.e. allow a new
> > optional genpd callback, get_performance_state() (just like
> > set_performance_state()), which can be called initially by the core to
> > get the performance to something other than zero. opp-set-rate is
> > there to set the performance state and enable the stuff as well.
> > That's why it looks incorrect in your case, where the function was
> > only required to be called once, and you are ending up calling it on
> > each resume. Limiting that with another local variable is bad as well.
>
> We discussed variant with get_performance_state() previously and Ulf
> didn't like it either since it still requires to touch 'internals' of GENPD.

Hmm, I wonder if that would be a problem since only genpd core is
going to call that routine anyway.

--
viresh