linux-kernel - Re: [RFC/PATCH 1/2] cpuidle: Allow idle-states to be disabled at start

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Message-ID: <57BDB2D8.4080507@linaro.org>
Date:   Wed, 24 Aug 2016 16:44:40 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Michael Neuling <michael.neuling@....ibm.com>,
        Paul Mackerras <paulus@...ba.org>,
        Vaidyanathan Srinivasan <svaidy@...ux.vnet.ibm.com>
Cc:     Anton Blanchard <anton@...ba.org>, linux-pm@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC/PATCH 1/2] cpuidle: Allow idle-states to be disabled at
 start

On 08/19/2016 12:26 AM, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>
> 
> Currently all the idle states registered by a cpu-idle driver are
> enabled by default. This patch adds a mechanism which allows the
> driver to hint if an idle-state should start in a disabled state. The
> cpu-idle core will use this hint to appropriately initialize the
> usage->disable knob of the CPU device idle state.

Why do you need to do that ?

> The state can be enabled at run time by echo'ing a zero to the sysfs
> "disable" control file.

... for each cpu.


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