One of the areas worked on by AMD Linux engineers recently to better optimize the Linux kernel on AMD Ryzen platforms is for lowering the power consumption in S5 state due to some devices not being put into a low power state when the system is powered off. Sent out today was the sixth iteration of these patches.
AMD engineer Mario Limonciello on Sunday posted the sixth iteration of these Linux kernel patches to help with the S5 power consumption. Mario explained with the patch cover letter:
“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, run their shutdown() callbacks.”
With better aligning to Microsoft Windows behavior where most of the OEMs validate and focus their efforts on, these Linux improvements should help with better S5 handling.
The v6 patches re-base the several dozen lines of code against the Linux 6.17-rc2 upstream state along with fixing a reported issue and updating some of the commit messages. See the v6 patch series for those interested in this work.
