The DRM documentation states:
> Unless explicitly specified (via CRTC property or otherwise), the active
> area of a CRTC will be black by default. This means portions of the active
> area which are not covered by a plane will be black, and alpha blending of
> any planes with the CRTC background will blend with black at the lowest zpos.
See https://dri.freedesktop.org/docs/drm/gpu/drm-kms.html#plane-abstraction
This means the view for the primary plane does not need to cover the
whole output and black areas of the scene-graph can be left out.
Doing so has various benefits - most importantly it:
1. allows us to use the plane-only path in more situations and with one
less plane, reducing memory bandwidth usage.
2. opens the path to offload arbitrary background colors in the future.
Iterate over the all visible paint nodes, remove solid-opaque-black
views so they are not considered for plane assignment and aggregate a
region that is later used to assign the primary plane.
Signed-off-by: Robert Mader <robert.mader@collabora.com>
Some client use subsurfaces with fully transparent single-pixel buffers
for various reasons, such as making it easier to order trees of
subsurfaces. As they are invisible we can simply ignore them in the
scene graph.
This allows us to use direct-scanout/plane-only in more circumstances,
as ensured in the test.
Signed-off-by: Robert Mader <robert.mader@collabora.com>
Recent improvements to llvmpipe made it possible to test dmabuf import
and offloading on vkms. Use our new client-buffer helper and the
presentation protocol to implement tests for simple offloading
scenarios.
Right now this is limited to the vkms default config, only providing us
with one primary and one cursor plane. In the future we can extend the
test to include more advanced scenarios.
Signed-off-by: Robert Mader <robert.mader@collabora.com>
