Right. The number of times I got an EINVAL just to discover yet another reason was quiet something :) (Is there a better way to discover the true reason other than scrolling back through dmesg?)
I'm also falling back to GL composition in some cases or while taking screenshots to avoid composing twice (HDMI + Writeback) if the scene is too complex or if other restrictions make that mandatory: Planes can only be rotated 0/180 degrees on the Pi HVS, so rotating a video to a portrait orientation is done on the GPU.
I'm also falling back to GL composition in some cases or while taking screenshots to avoid composing twice (HDMI + Writeback) if the scene is too complex or if other restrictions make that mandatory: Planes can only be rotated 0/180 degrees on the Pi HVS, so rotating a video to a portrait orientation is done on the GPU.