Linux 5.6 Adds New CPU Cooling Mechanism With Generic Idle Cooling Driver

The new "cpuidle_cooling" thermal driver in Linux 5.6 is similar to Intel's PowerClamp driver and RAPL framework but is generic for working across CPUs/architectures as an idle cooling driver to cool down CPUs/SoCs by injecting idle cycles at run-time.

This new CPU idle cooling thermal driver is similar to Intel's Idle / PowerClamp / RAPL solution but not limited to a specific CPU architecture and not needing any extra framework. This driver will inject idle cycles at run-time when necessary to cool down the CPU and also reduce any static power leakage. Activating this CPU idle cooling driver can be done with setting a trip point that can also be used as a fall-back should the Linux CPUFreq drivers not be working optimally for controlling the CPU core frequencies.

More details on this new CPU idle injection solution via this documentation. This new driver was led by the Linaro team.

The thermal updates for Linux 5.6 also include HWMON support for Rockchip, thermal sensor support for Allwinner H6/H5/H3/A64/A83T/R40 sun8i platforms, a Broadcom BCM2711 thermal driver (the SoC used on the Raspberry Pi 4), Jasper Lake support within the Intel int340x driver, Comet Lake support within the Intel PCH code, and other fixes. The complete list of thermal details via this mailing list post.