IPU3CameraData stores requests that have been failed due to a buffer shortage. The requests should be retried once enough buffers are available. This sets the retry function as signal to CIO2Device and IPU3Frame, and invokes it from CIO2Device::tryReturnBuffer() and IPU3Frame::remove(). Signed-off-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>