Seeing this as well, running xbmc initially, but tested with extreme-tuxracer with the same effects.
Environment: gentoo x86 2.6.31-gentoo-r6 media-tv/xbmc-9.11-r1 (Confluence skin, no unusual plugins/scripts)
01:00.0 VGA compatible controller: ATI Technologies Inc RV370 5B60 [Radeon X300 (PCIE)]
media-libs/mesa-7.5.2 x11-base/xorg-server-1.6.5-r1 x11-drivers/xf86-video-ati-6.12.4 x11-libs/libdrm-2.4.15
Seeing this as well, running xbmc initially, but tested with extreme-tuxracer with the same effects.
Environment: xbmc-9. 11-r1 (Confluence skin, no unusual plugins/scripts)
gentoo x86 2.6.31-gentoo-r6
media-tv/
01:00.0 VGA compatible controller: ATI Technologies Inc RV370 5B60 [Radeon X300 (PCIE)]
media-libs/ mesa-7. 5.2 xorg-server- 1.6.5-r1 xf86-video- ati-6.12. 4 libdrm- 2.4.15
x11-base/
x11-drivers/
x11-libs/