it is regression, but is it nouveau bug?:
# bad: [4d6fab245eec3880e2a59424a579851f44857ce8] cso: don't track the number
of sampler states bound
git bisect bad 4d6fab245eec3880e2a59424a579851f44857ce8
# good: [c8459846905bf7adfb6b5010a77aee9269228bdb] st/mesa: sink and simplify
texBaseFormat getting for sampler states
git bisect good c8459846905bf7adfb6b5010a77aee9269228bdb
# first bad commit: [4d6fab245eec3880e2a59424a579851f44857ce8] cso: don't track
the number of sampler states bound