linux-kernel - Re: [PATCH 2/4] opp: Track device's resources configuration status

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Message-ID: <20200817050434.cisjgwo4lxl652fb@vireshk-mac-ubuntu>
Date:   Mon, 17 Aug 2020 10:35:28 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Stephen Boyd <sboyd@...nel.org>
Cc:     Nishanth Menon <nm@...com>, Viresh Kumar <vireshk@...nel.org>,
        linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Rafael Wysocki <rjw@...ysocki.net>, mka@...omium.org,
        sibis@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/4] opp: Track device's resources configuration status

On 15-08-20, 01:03, Stephen Boyd wrote:
> Quoting Viresh Kumar (2020-08-12 21:28:59)
> > The OPP core needs to track if the resources of devices are enabled or
> > configured or not, as it disables the resources when target_freq is set
> > to 0.
> > 
> > Handle that with a separate variable to make it easy to maintain.
> > 
> > Also note that we will unconditionally call clk_set_rate() in the case
> > where the resources are getting enabled again. This shouldn't have any
> > side effects anyway.
> 
> Any reason to want to do that?

To avoid more flags, code paths and simplicity of the code. And this
should normally happen in a corner case as well, like calling
set-rate(0) from suspend and then reinitializing things again in
resume.

> We'll have to grab the prepare lock in
> the clk framework to figure out that there's nothing to do sometimes. If
> anything, a comment may help to indicate that we call clk_set_rate()
> again, but don't expect it to matter much.

Ok.

-- 
viresh