From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH V3 7/8] ARM: cpuidle: Register per cpuidle device Date: Mon, 23 Mar 2015 15:42:01 +0100 Message-ID: <55102639.4000305@linaro.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150321203546.GE22354@red-moon> Sender: linux-kernel-owner@vger.kernel.org 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" List-Id: linux-pm@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= =2E >> >> 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 suppo= rt > 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, w= e 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 proper= ly. Ok, I think that needs more discussion. I will drop this patch from my patchset as we agreed on the other=20 patches and resubmit. -- Daniel --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog