Add to the FrameBuffer::Private class a unique pointer to a
Fence.
The Fence will be used to signal the availability of the Framebuffer for
incoming data transfer.
The Fence will be associated to a FrameBuffer at Request::addBuffer()
time, and if correctly signalled, reset by the core at Request queue
time.
If a FrameBuffer completes with errors, due to a Fence wait failure, the
Fence will still be owned by the FrameBuffer and it is application
responsibility to correctly reset it before reusing the buffer.
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>