From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752637AbbCWOmJ (ORCPT ); Mon, 23 Mar 2015 10:42:09 -0400 Received: from mail-wg0-f45.google.com ([74.125.82.45]:34197 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752363AbbCWOmF (ORCPT ); Mon, 23 Mar 2015 10:42:05 -0400 Message-ID: <55102639.4000305@linaro.org> Date: Mon, 23 Mar 2015 15:42:01 +0100 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Lorenzo Pieralisi CC: "rjw@rjwysocki.net" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , "robherring2@gmail.com" , "arnd@arndb.de" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "lina.iyer@linaro.org" , "sboyd@codeaurora.org" Subject: Re: [PATCH V3 7/8] ARM: cpuidle: Register per cpuidle device References: <1426851841-2072-1-git-send-email-daniel.lezcano@linaro.org> <1426851841-2072-8-git-send-email-daniel.lezcano@linaro.org> <20150321203546.GE22354@red-moon> In-Reply-To: <20150321203546.GE22354@red-moon> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/21/2015 09:35 PM, Lorenzo Pieralisi wrote: > On Fri, Mar 20, 2015 at 11:44:00AM +0000, Daniel Lezcano wrote: >> Some architectures have some cpus which does not support idle states. >> >> Let the underlying low level code to return -ENXIO when it is not >> possible to set an idle state. > > Well, this is getting interesting. We are parsing possible CPUs to > detect if they have common idle states in DT. If a CPU does not support > idle states, the cpu node for that CPU should not define any idle > state. > > The approach above will work with my heterogenous system patch, since > the respective CPUidle driver mask will be created by parsing the DT > idle states. > > http://www.spinics.net/lists/arm-kernel/msg403190.html > > In current approach if a "possible " CPU does not have idle states, we do > not init CPUidle at all. > > So, to cut a long story short, what does "a cpu does not support idle > states" mean ? > > Does it mean that firmware defines idle states for that CPU in DT but > initializing them fail ? > > I am fine with this patch, but we need to define -ENXIO return properly. Ok, I think that needs more discussion. I will drop this patch from my patchset as we agreed on the other patches and resubmit. -- Daniel -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog