OK, I have made a mistake and tested some combinations.
radeon 7.9.0 + mesa 12.0.6 is buggy radeon 7.9.0 + mesa 17.0.7 is buggy radeon 7.7.0 + mesa 12.0.6 is not buggy radeon 7.7.0 + mesa 17.0.7 is not buggy
So, I think the bug is still in radeon 7.9.0.
OK, I have made a mistake and tested some combinations.
radeon 7.9.0 + mesa 12.0.6 is buggy
radeon 7.9.0 + mesa 17.0.7 is buggy
radeon 7.7.0 + mesa 12.0.6 is not buggy
radeon 7.7.0 + mesa 17.0.7 is not buggy
So, I think the bug is still in radeon 7.9.0.