http://bugs.winehq.org/show_bug.cgi?id=12416
--- Comment #23 from Stefan Dösinger stefandoesinger@gmx.at 2008-04-13 05:06:24 --- The bug affects all radeon cards with the fglrx driver, and possibly radeon 9500 and newer cards with the open source driver.
As for the regression slipping through: The testsuit has all the tests it needs for catching this issue, the problem is that nobody runs them on the ATI driver. And even if someone ran them the regression would maybe have slipped through because many tests fail due to driver bugs anyway.