Draft: stable/linux-dmabuf: allow compositors to advertise multiple devices
With multi gpu systems, clients rendering on a GPU different to the main device usually have to copy the buffer to the main device in order to ensure the compositor can import it. In the case where the image is then presented on the GPU that the client was initially rendering on, this causes two unnecessary additional copies: One to the main device, and one back to the original GPU.
With the changes in this commit, compositors can advertise that they're able to import buffers for sampling on multiple GPUs. This way the compositor becomes responsible for copying the buffer to the appropriate GPU(s) and can skip the copies whenever feasible.
Signed-off-by: Xaver Hugl xaver.hugl@gmail.com