On Sun, Oct 01, 2023 at 09:27:01PM +0530, Manivannan Sadhasivam wrote: > On Fri, Sep 29, 2023 at 05:16:16PM +0100, Caleb Connolly wrote: > > The Thermal Mitigation Device (TMD) Service is a QMI service that runs > > on remote subsystems (the modem and DSPs) on Qualcomm SoCs. > > It exposes various mitigations including passive thermal controls and > > rail voltage restrictions. > > > > This series introduces support for exposing TMDs as cooling devices > > in the kernel through the thermal framework, using the QMI interface. > > > > Each TMD client is described as a child of the remoteproc node in > > devicetree. With subnodes for each control. > > > > Daniel expressed concerns in the past aganist representing TMD driver as a > cooling device since it is not tied to thermal zones and the governors cannot > use it. Instead he suggested to represent it as a powercap device with thermal > constraints. > > So please look into that approach. > The powercap framework revolves around the idea that we have some amount of power (micro-watt) being available to the system, which can be split across a range of devices. Say that we implement this as a powercap thing, what current consumption would you attribute these entires? How would you map a given uW value to the mitigation levels provided by the qmi-cooling instances? Beyond that, I'm still not sure how we would plug this in. We don't have a picture of the power consumption/flow through the system at any point in time - as the control of the power grid is distributed across the various subsystems. Regards, Bjorn
