https://bugs.freedesktop.org/show_bug.cgi?id=25871
--- Comment #3 from Alex Deucher agd5f@yahoo.com 2011-02-28 18:27:18 PST --- For point sampled textures, SQ_TEX_SAMPLER_WORD2_0.MC_COORD_TRUNCATE needs to be set to 1. The default behavior for texture addressing is to round unless that bit is set.