While Linaro has strong ties to the Ubuntu community, Linaro developers continue to be working on Wayland over Mir and a developer has now published the latest revision to Wayland's DMA-BUF support.
Benjamin Gaignard of Linaro has been working to support DMA-BUF inside Wayland/Weston. With this, it would be possible to pass DMA-BUF file descriptors inside Wayland/Weston for passing buffers instead of relying upon Mesa EGL and being more efficient than using the wl_shm shared memory where an extra copy would be involved in moving buffers.
The wl_dmabuf protocol is added as a result of this work, including the changes to support it within Weston and a simple example too. The patch-set is now up to its fourth revision and can be found on the Wayland-devel list
This work is too late for the upcoming featureful Wayland/Weston 1.4 release
but it hopefully could make it for the next major release, Wayland/Weston 1.5.