AMD Radeon Linux Graphics Driver Prepares PSR2 / PSR-SU MPO Capability

For better power-savings with new/forthcoming AMD powered laptops, this week AMD engineers sent out a patch series for PSR2 / PSR-SU MPO functionality for reducing display power consumption.

Sent out on Thursday were 17 patches wiring up PSR-SU MPO support for the AMDGPU DC display code.

PSR-SU MPO in this context stands for Panel Self Refresh, Selectively Updated, Multi-Plane Overlay. PSR-SU is also marketed as PSR2 for eDP laptop panels. PSR2/PSR-SU allows for expanded power-savings over the original PSR power-savings tech. Rather than being limited to power-savings when there are no changes/damage to the screen contents, this refined tech allows for selectively updating changed regions of the screen.

The PSR "selectively updated" handling obviously requires tighter operating system integration to communicate the damaged regions. While ideally this would be communicated effectively by the various Wayland compositors, that isn't the case today. This multi-plane overlay aspect is designed to partially overcome today's compositor limitations by at least allowing this power-savings functionality to work for multi-plane overlay with the plane bounds being used to define the damaged region. The cursor is also tracked for the old/new cursor positions for damaged areas.

See this patch series for more details on the PSR-SU MPO functionality for better power-savings with capable eDP display hardware on AMD laptops. Intel's open-source engineers for their part have been working on PSR2 power-savings support going back a few years.