linux-kernel - Re: [PATCH V2 1/3] OPP: Level zero is valid

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Date:   Tue, 31 Oct 2023 10:56:27 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Stephan Gerhold <stephan.gerhold@...nkonzept.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2 1/3] OPP: Level zero is valid

On 30-10-23, 19:47, Konrad Dybcio wrote:
> On 30.10.2023 11:24, Viresh Kumar wrote:
> > The level zero can be used by some OPPs to drop performance state vote
> > for the device. It is perfectly fine to allow the same.
> > 
> > _set_opp_level() considers it as an invalid value currently and returns
> > early.

> So, currently if the device is PM-enabled, but OPP requirements are lifted,

How exactly are the OPP requirements lifted ?

By calling dev_pm_opp_set_opp(dev, NULL) ?

This will work fine even without this commit.

> is the API currently internally stuck at the last non-zero level?
> 
> Just trying to understand if this could fix some silent issues

Also the issue I am trying to solve here came in existence only during the 6.7
merge window and doesn't affect the genpds linked via required-opps. And this
commit will soon be merged.

-- 
viresh