![]() "/etc/default/grub" for a more permanent solution). To avoid loading ACPI CPUFreq even if it's built-in, the "initcall_blacklist=acpi_cpufreq_init" option can be set in your /boot/grub/grub.cfg or respective place for editing your kernel command line options at boot (e.g. On most (all?) distribution kernels the ACPI CPUFreq driver is built into the kernel and not a module, so simply blacklisting it will not work. If you don't see CONFIG_X86_AMD_PSTATE and it's commented out or "n", you would need to first rebuild your kernel so that driver is included. Most other distro kernel builds will at least likely have the CONFIG_X86_AMD_PSTATE=m option enabled so it's at least built. ACPI CPUFreq is the default still with their Linux 5.17+ kernel builds but the AMD P-State module is included as part of the kernel builds. This guide was written making use of Ubuntu with their Ubuntu Mainline Kernel PPA kernel builds. Many motherboard vendors do have a "ACPI CPPC" option in the BIOS that can be set to enabled or auto on Zen 2 and newer processors. You also need to ensure CPPC is enabled in your BIOS in case it happened to be disabled. AMD P-State depends upon ACPI Collaborative Processor Performance Contols (CPPC) and that is only with Zen 2 and newer - Zen 1 / Zen 1+ will not be seeing any support. As a reminder, AMD P-State is only supported with AMD Zen 2 processors and newer. In any case, if wanting to use amd_pstate on Linux 5.17 today here is a brief how-to guide for making the transition.įirst up, the easiest way to check to verify your CPU frequency scaling driver is by reading /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver to see if you are on acpi-cpufreq or amd-pstate. Right now this driver isn't the default over ACPI CPUFreq and I haven't seen any Linux distribution vendors announce their plans to immediately default to this new driver, but over the months ahead I expect that to change. Since the release of the Linux 5.17 kernel the leading question in my inbox has been from readers asking how to actually make use of the AMD P-State driver.
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