From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Armstrong Subject: Re: [PATCH 1/6] arm64: dts: amlogic: Add missing cooling device properties for CPUs Date: Sat, 26 May 2018 10:37:49 +0200 Message-ID: <9f9cc086-6069-afbc-d3c6-46608ff35b79@baylibre.com> References: <2a2eb28da9fecf129f6bc0ab3d3748d9f4d25a29.1527225682.git.viresh.kumar@linaro.org> <20180525211025.c73zdcdtyuvlewng@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180525211025.c73zdcdtyuvlewng@localhost> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Olof Johansson , Viresh Kumar Cc: Mark Rutland , devicetree@vger.kernel.org, Vincent Guittot , arm@kernel.org, Catalin Marinas , Daniel Lezcano , Will Deacon , linux-kernel@vger.kernel.org, Rob Herring , Kevin Hilman , Carlo Caione , chris.redpath@arm.com, linux-amlogic@lists.infradead.org, ionela.voinescu@arm.com, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org Hi, On 25/05/2018 23:10, Olof Johansson wrote: > On Fri, May 25, 2018 at 11:10:01AM +0530, Viresh Kumar wrote: >> The cooling device properties, like "#cooling-cells" and >> "dynamic-power-coefficient", should either be present for all the CPUs >> of a cluster or none. If these are present only for a subset of CPUs of >> a cluster then things will start falling apart as soon as the CPUs are >> brought online in a different order. For example, this will happen >> because the operating system looks for such properties in the CPU node >> it is trying to bring up, so that it can register a cooling device. >> >> Add such missing properties. > > This seems awkward compared to just having one cooling-cells in the /cpus node > instead. > > What's it used for? I don't see any properties in the device nodes on meson-gxm > that have any cooling-foo cells in them? So why should #cooling-cells be > needed? There is no reason to have the cooling-cells on these other CPUs, the DVFS is controlled on the first CPU of each cluster, here cpu0 and cpu4 and only cpu0 and cpu4 are used as cooling-cells. Neil > > > -Olof > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >