Walthar, viscount of Narbonne (and Macon),+911

Settipani's article in ''Onomastique et Parente" about the
Chateaudun-viscounts mentions in the first table a Walthar
[o885-90,+911/6] as victe/viscount of Narbonne, son of Maiolus, in the
same role, being a sideline of the Alberic's and Leotald's in the same
role, and these later also as viscount of Macon, but does not give
further descendance of this Walthar.

Reading the 80-year old book of Maurice Chaume on the origins of the
Frankish duchy of Burgundy, in table 3 about ''Les Bouchard et les
Aubri", I read about this same Walthar/ Gautier, now mentioned as
viscount of Macon , with a son Mayeul (Maiolus)<932-943>, also with
sons Gautier II <948-961>, still as viscount of Macon, and Jean
<972-977/80>, bishop of Macon

I have not got the 1993-article of Thierry Strasser about the viscounts
of Narbonne, but the French Wikipedia, referring to this article, does
not mention any of the above names in such role.

The role of viscount of Macon was created by Bernard Plantavelue when
he moved from the south of France (Narbonne/Septimanie) back to the
Auvergne where he also took control of Macon (including the
Cluny-area). For sure, the viscounts of Narbonne travelled with him and
took the same role in Macon, later as counts.

can you help me understand more about these Walters (especially Walter
II) ?

thanks, Wim