Vega 10 & Newer Getting More Fine-Grained PowerPlay Controls On Linux

With the upcoming Linux 5.1 kernel cycle, discrete Radeon graphics cards based on Vega 10 and newer will have fine-grained controls over what PowerPlay power management features are enabled and the ability to toggle them at run-time.

Queued into the work-in-progress AMDGPU code for the eventual Linux 5.1 kernel cycle is now a ppfeatures for sysfs. This new "ppfeatures" file on sysfs will allow for querying the PowerPlay features state and toggling them individually. This includes features like GFXOFF (the ability to turn off the graphics engine when idling), automatic fan control, LED display for GPU activity, the dynamic power management state for the various blocks, and other features. Up to now the PowerPlay features couldn't be toggled individually but just a blanket enable/disable.

Also for Vega 10 and newer dGPUs with this next Linux kernel will be pp_dpm_socclk for being able to read and adjust the SOC clock power levels. Likewise, pp_dpm_fclk but that interface will be just for Vega 20 and newer. Rounding out these PowerPlay additions is a pp_dpm_dcefclk for adjusting its value on Vega 10 and newer. Though without any full-featured AMDGPU GUI control panel for Linux, users will be left to manually tinkering with their values via the sysfs files.

Outside of the PowerPlay space, the AMDGPU code being worked on for Linux 5.1 also adds support for self IRQ on Vega 10 with the processing of rings one and two. This work and more (including dropping the old Sea Islands dynamic power management code) is currently building up in drm-next-5.1-wip.