So that it can be set properly prior to set up output fields.  That
makes easy to handle/warn errors during the setup since it doesn't
need to be bothered with the GUI.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1400480762-22852-11-git-send-email-namhyung@kernel.orgSigned-off-by: Jiri Olsa <jolsa@kernel.org>