linux-kernel - Re: [PATCH V2 5/6] PM / domain: Save/restore performance state at runtime suspend/resume

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Message-ID: <20170220091848.GQ21911@vireshk-i7>
Date:   Mon, 20 Feb 2017 14:48:48 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Kevin Hilman <khilman@...libre.com>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, ulf.hansson@...aro.org,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        sboyd@...eaurora.org, nm@...com, robh+dt@...nel.org,
        lina.iyer@...aro.org, rnayak@...eaurora.org
Subject: Re: [PATCH V2 5/6] PM / domain: Save/restore performance state at
 runtime suspend/resume

On 17-02-17, 15:58, Kevin Hilman wrote:
> Viresh Kumar <viresh.kumar@...aro.org> writes:
> 
> > With runtime PM, the devices get suspended while the system is up and
> > running in order to save power. At such times, it is important to
> > re-evaluate the required performance state of the domain, in order to
> > choose a lower state if possible.
> >
> > This patch updates the genpd suspend/resume callbacks to do that.
> >
> > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> 
> Doesn't this assume that a device in the domain would need to change
> performance state while runtime suspended.  How would that happen?
> 
> Rather than adding this here, I would think that drivers would instead
> remove any QoS requests before going into runtime suspend, which would
> trigger an update before runtime suspending.

Okay, lets leave it for the drivers, at least for the time being. I
will drop this patch.

-- 
viresh