From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x233.google.com (mail-wm0-x233.google.com [IPv6:2a00:1450:400c:c09::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3sK9cx0mS5zDrJy for ; Thu, 25 Aug 2016 01:06:40 +1000 (AEST) Received: by mail-wm0-x233.google.com with SMTP id o80so32541173wme.1 for ; Wed, 24 Aug 2016 08:06:40 -0700 (PDT) Subject: Re: [RFC/PATCH 1/2] cpuidle: Allow idle-states to be disabled at start To: Balbir Singh , "Gautham R. Shenoy" , "Rafael J. Wysocki" , Michael Ellerman , Benjamin Herrenschmidt , Michael Neuling , Paul Mackerras , Vaidyanathan Srinivasan References: <48afad7788300482c047fc35e70ca8e4bf31a5ac.1471557381.git.ego@linux.vnet.ibm.com> <57BDB2D8.4080507@linaro.org> Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Anton Blanchard , linux-pm@vger.kernel.org From: Daniel Lezcano Message-ID: <57BDB7F7.3090502@linaro.org> Date: Wed, 24 Aug 2016 17:06:31 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/24/2016 04:48 PM, Balbir Singh wrote: > > > On 25/08/16 00:44, Daniel Lezcano wrote: >> On 08/19/2016 12:26 AM, Gautham R. Shenoy wrote: >>> From: "Gautham R. Shenoy" >>> >>> 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 ? >> > > I think patch 2/2 explains the reason as it uses this infrastructure Ok, let me elaborate the question, I was not clear. Why the userspace can't setup the system environment at boot time by disabling the state instead of adding extra code to disable it at boot time in the kernel and then re-enable it from userspace ? -- Daniel -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog