linux-kernel - Re: [PATCH] opp: Provide a function for just setting bandwidth

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Message-ID: <485cd9cf-6a0d-4a1e-0212-9afc1a41a10b@linaro.org>
Date:   Mon, 29 May 2023 13:38:28 +0200
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>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] opp: Provide a function for just setting bandwidth



On 29.05.2023 11:40, Viresh Kumar wrote:
> On 29-05-23, 11:35, Konrad Dybcio wrote:
>> I think I didn't state my intentions correctly..
>>
>> The proposed function would set *just* the bandwidth through OPP,
>> so it'd be essentially equal to
>>
>> loop over num_paths {
>> 	icc_get(...)
>>
>> 	icc_set(...)
>>
>> 	icc_put(...)
>> }
> 
> Right, but why do you need to do it ? Why isn't this done as part of
> dev_pm_opp_set_{freq|opp}() ?
> 
>> but since OPP already picked up these interconnect paths, it makes
>> little sense to mess with them through raw APIs.
> 
> I am not sure if I would want to expose an API to just configure part of the
> entire OPP switching mechanism. I would rather let you do that via ICC APIs,
> instead of going through the OPP core. Since there is a possibility of
> accidental misuse of the same here.
I did some more testing and I think that I was just trying to abuse
the APIs.. Adding power-domains + pm calls + required-opps to the genpd
provider made the set_opp func work fine on suspend.. Consider this
solved!

Konrad
>