AMD Linux Patches Aim To Improve S5 Power Consumption

Written by Michael Larabel in AMD on 10 June 2025 at 04:00 AM EDT. 9 Comments

An ongoing area of work for AMD's Linux client team is on enhancing the power management and overall power savings/efficiency support for Ryzen platforms on Linux. An updated patch series was posted on Monday for making the system S5 power state handling more ideal when powering off the system.

AMD Linux engineer Mario Limonciello posted the latest patches this week for improving S5 power consumption. These patches change the Linux power management code to use hibernate flows for system power off, putting PCI Express ports with downstream devices into D3 mode at hibernate, avoid evicting resources at S5 for the AMDGPU DRM graphics driver, and hooking SCSI and USB code into system suspend callbacks.

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Limonciello explained with the patch series:

"A variety of issues both in function and in power consumption have been raised as a result of devices not being put into a low power state when the system is powered off.

There have been some localized changes to PCI core to help these issues, but they have had various downsides.

This series instead tries to use the S4 flow when the system is being powered off. This lines up the behavior with what other operating systems do as well. If for some reason that fails or is not supported, unwind and do the previous S5 flow that will wake all devices and run their shutdown callbacks."

We'll see if this work gets wrapped up in time for the Linux v6.17 kernel for in turn being able to make it into the likes of Ubuntu 25.10 this autumn. In any event AMD's continued Linux Ryzen client platform optimization work continues to be quite promising.