
Back in late 2021 was the publishing of the eDP 1.5 specification by VESA. The eDP 1.5 spec is backwards compatible with eDP 1.4 while adding an improved Panel Self Refresh (PSR) protocol, improved Adaptive-Sync, and other updates. Among those other changes is adding a 6.75 Gbps/lane option for panels.
The AMDGPU DC code is getting ready for supporting eDP 1.5 panels with 6.75 Gbps/lane and today's patch series makes those preparations. But with not yet having any eDP 1.5 panels supporting that rate, the Linux driver is only exposing that mode when the driver is built with a new "support_eDP1_5" debugging option.
The 6.75 Gbps/lane / eDP 1.5 preparations are part of today's AMDGPU DC patch series . Also part of that patch series is an FPO optimization that for some configurations could help in achieving a lower voltage for the GPU.