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

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Date:   Tue, 31 Oct 2023 11:07:53 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     Viresh Kumar <viresh.kumar@...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 31.10.2023 06:26, Viresh Kumar wrote:
> 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.
Ok!

> 
>> 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.
Ack, thanks

Konrad