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[71.255.246.27]) by smtp.gmail.com with ESMTPSA id n25sm14066118qkk.76.2020.06.16.10.24.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Jun 2020 10:24:23 -0700 (PDT) Subject: Re: [PATCH v6 0/6] Introduce Power domain based warming device driver To: Pavel Machek Cc: rui.zhang@intel.com, ulf.hansson@linaro.org, daniel.lezcano@linaro.org, bjorn.andersson@linaro.org, agross@kernel.org, robh@kernel.org, amit.kucheria@verdurent.com, mark.rutland@arm.com, rjw@rjwysocki.net, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200604015317.31389-1-thara.gopinath@linaro.org> <20200616105325.GH1718@bug> From: Thara Gopinath Message-ID: <0eb2e140-9c9c-4777-9916-d81eddc793ca@linaro.org> Date: Tue, 16 Jun 2020 13:24:16 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200616105325.GH1718@bug> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/16/20 6:53 AM, Pavel Machek wrote: > Hi! > >> Certain resources modeled as a generic power domain in linux kernel can be >> used to warm up the SoC (mx power domain on sdm845) if the temperature >> falls below certain threshold. These power domains can be considered as >> thermal warming devices. (opposite of thermal cooling devices). > > Would you explain when this is needed? > > I'd normally expect "too low" temperature to be a problem during power-on, but at > that time Linux is not running so it can not provide the heating... Hi Pavel, This is more in the scenario if the system in on and temperature is dipping (I have been told in colder climates). Idea is to turn on resources so as to prevent further dipping of temperature if possible. > > Best regards, > > Pavel > -- Warm Regards Thara