This series improves the handling of alpha formats with the VC4 HVS compositor. Alpha formats are marked as premultiplied as is standard for DRM. Further fix a display corruption issue when planes with per-pixel alpha try blending from the (nonexistent) background by selectively enabling a black background color fill.
This series follows the changes suggested by Eric Anholt in a previous patch discussion:
https://patchwork.freedesktop.org/patch/207667/
A simple test program for the display corruption issue is available:
https://github.com/stschake/vc4-alpha-test
Stefan Schake (3): drm/vc4: Set premultiplied for alpha formats drm/vc4: Check if plane requires background fill drm/vc4: Enable background color fill when necessary
drivers/gpu/drm/vc4/vc4_crtc.c | 22 ++++++++++++++++++++++ drivers/gpu/drm/vc4/vc4_drv.h | 6 ++++++ drivers/gpu/drm/vc4/vc4_plane.c | 16 +++++++++++++++- drivers/gpu/drm/vc4/vc4_regs.h | 1 + 4 files changed, 44 insertions(+), 1 deletion(-)