Related to the work by Mike Blumenkrantz for significantly improving the Mesa glReadPixels performance by more than 100%, the open-source driver developer at Valve has now enabled compute PBO blits within mainline Mesa for the AMD Radeon "RadeonSI" Gallium3D driver.

Compute pixel buffer object (PBO) blits are now enabled for the RadeonSI driver. Blumenkrantz quipped in the pull request :

"radeonsi: enable compute pbo blits

this probably needs better tuning by experts, but it massively improves perf in a number of cases"

This in turn will trigger the compute PBO downloads for glReadPixels once that other merge request lands plus other unspecified test cases.

The compute PBO blits for RadeonSI was merged today for next quarter's Mesa 24.2 feature release.