In preparation for the Linux 7.3 merge window, the Linux power management subsystem maintainer, Rafael Wysocki, submitted comprehensive updates covering power management, ACPI, and thermal control. Reflecting the industry focus, the core changes for the 7.3 kernel are heavily influenced by improvements submitted for both Intel and AMD hardware drivers.
Intel Driver Enhancements
Significant updates were made to the Intel P-State CPU frequency scaling driver. These changes include mechanisms for correctly transmitting maximum performance values, enhanced performance handling when operating in performance policy mode, and refined calculations for frequency values. Furthermore, the driver introduces improved hardware P-State (HWP) handling specifically designed for older Intel Broadwell processors.
The Intel Idle driver has also been updated for Linux 7.3. To address certain device handling issues, the driver now avoids entering deep idle states during the initialization process. Additionally, the driver now supports the ACPI _LPI low power idle object, alongside various other fixes implemented within the Intel driver codebase.
AMD and System-Level Power Control
For AMD hardware, the P-State driver has been updated to include dynamic EPP (Energy Performance Preference) with per-core granularity. The AMD P-State driver also incorporates fixes for initialization issues and now ensures that the minimum limit frequency is correctly set based on the BIOS minimum performance value.
Beyond specific vendor updates, the general power management code benefits from updates to Rust bindings. Furthermore, a major ACPI pull request was submitted which eliminates the traditional acpi_driver structure and introduces numerous fixes across various sections of the ACPI code.
Thermal and Core Functionality
Rafael Wysocki also provided key updates related to thermal control. Among the notable improvements is the addition of support for directed package-level thermal interrupts on Intel CPUs. This architectural efficiency enhancement allows a single CPU core to manage package-level thermal interrupts, preventing the need to broadcast these signals to every core.
In summary, these comprehensive updates for the Linux 7.3 merge window aim to improve system efficiency, stability, and performance handling across a wide range of Intel and AMD hardware components.
