I have same problem with card AMD Radeon HD 7730. When glamor is enabled I see
same screen corruption (as in attached screenshot) in Xserver (also in login
screen KDM). When glamor is disabled everything is OK, but very very slow.
Problem is still present in mesa, drm, xorg ati - all from git from end of
December. Problem is also in Fedora live CD which has enabled radeonsi and
glamor by default. Enabling/Disabling ColorTiling and ColorTiling2D did not
help I still saw same problem.