https://bugs.freedesktop.org/show_bug.cgi?id=31013
--- Comment #9 from Alex Deucher agd5f@yahoo.com 2010-10-21 13:42:48 PDT --- r3xx/r4xx actually supports 4 indirections, so if the current code is limiting it to 3, it should be upped to 4. See US_CONFIG.NLEVEL