By admin 
Today’s batch of AMDGPU Display Code “DC” updates bring a few noteworthy items for benefiting modern hardware under Linux.
The new set of AMDGPU DC code updates for their open-source Linux driver bring a few noteworthy items along with a ton of test case additions to hopefully help preserve quality and prevent regressions moving forward.
Catching my eye with today’s AMDGPU DC patch churn is the enabling of “CACP” on Linux. This is said to help OLED display panels save more power on Linux. CACP in this context is short for the Content Adaptive Contrast and Power feature and is part of the AMD Adaptive Backlight Management (ABM) handling.
No numbers to quantify the relative power-savings were brought up in the patch message or code comments. Searching for AMD Content Adaptive Contrast and Power also didn’t reveal much. In any event it will be interesting to see if this presents a noticeable power-savings for OLED display panel usage under Linux.
Some of the copyright comments in the code reflect AMD code from 2022, so it appears this power-savings feature has for quite a while already been in use with their Windows drivers.
Today’s DC patches also enable Panel Self Refresh (PSR) and Panel Replay on the DCN42b variant for greater power savings for that specific display IP. IPS support is enabled in a separate patch for DCN42b as another power-savings feature… Seemingly a big focus of today’s patch drop for Linux.
With the patches there is separately also a fix for 8K mode parsing when not parsed by the display EDID. Due to AMDGPU handling, some 8K@120 and 8K@240 timings might not be properly parsed via DisplayID extension blocks as part of the HDMI 2.1 handling. That is being fixed with the new patches.
These new patches are out on the amd-gfx mailing list. Given the timing these patches are likely to be queued for the Linux v7.3 cycle.