https://bugs.freedesktop.org/show_bug.cgi?id=39202
--- Comment #30 from Siganderson dj_def@webmail.it 2011-08-18 05:06:35 PDT --- I even tried do compile a 2.6.39 kernel with the old drm.h drm_ioctl.c drm_irq.c files (when the incriminated commit was not yet applied) and as expected I had 100 FPS in kde when vsync is on in kde destkop effects settings.