Significant ACPI & Power Management Changes In Linux 3.19

Written by Michael Larabel in Linux Kernel on 9 December 2014 at 09:15 AM EST. Add A Comment
Rafael Wysocki of Intel mailed in the ACPI and power management changes for the Linux 3.19 merge window. As said by the ACPI/PM subsystem maintainer, "This time we have some more new material than we used to have during the last couple of development cycles."

Of interest to most Phoronix readers is that the Intel P-State driver now supports hardware P-States. This Intel CPU scaling driver for modern CPUs now uses CPUID to check whether a feature is supported by the processor, when enabling features by default.

The ACPI/PM changes also have a unified interface for accessiing device properties provided by platform firmware, support for a platform firmware interface based on ACPI regions used in PMIC chips on Bay Trail hardware, ACPI core improvements, and a CPUfreq driver for the Loongson 1B processor.

The full write-up on what these power related changes mean for the Linux 3.19 kernel can be found via the 3.19 merge window pull request.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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