A few days ago there was a KDE review request submitted by AMD's Jammy Zhou for white-listing the AMD Catalyst driver for KWin direct rendering. Jammy Zhou wrote, "With latest Catalyst Linux drivers (8.973/8.98 and later), the direct rendering can work well now...The return value of opengltest is correct for different AMD Catalyst driver versions."
Martin Gräßlin, the lead KWin maintainer, has confirmed this change for KDE 4.10 via his blog:
But the work on 4.10 is rather impressive and really important. First of all I want to thank Jammy Zhou for adapting our OpenGL test application to determine whether the Catalyst driver supports direct rendering with compositing. Thanks to that change KWin will default to direct rendering and OpenGL 2 on the latest Catalyst drivers (in fact KWin defaults to direct rendering on all drivers now). If you are already using a recent Catalyst version you can also set the environment variable “KWIN_DIRECT_GL” to “1″ to enforce direct rendering, no matter what the test app thinks. This works with all currently supported KWin versions.This news comes after back in February I wrote AMD would work to properly support KWin with Catalyst following news that they want to drop the old KWin GL1 renderer and that would cause problems for Catalyst and old GPUs.
KDE 4.10 should be released in late January of 2013.