Comment 23 for bug 306605

I have the same problem with an NVidia on-board chipset GeForce 6150 (Asus N2NPV-VM, latest bios 1401) since upgrading to Ubuntu 9.04 amd64.

The problem is apparent, regardless of the used xorg-driver (have xorg-edgers in my apt-sources and tried everything: nouveau, nvidia 180, 173, 96 and even nv!) or regardless of compiz being turned on.

I made a few screenshots to illustrate the problem. In the attached screenshots, you can see that apparently refreshing a widgets background fails, so the problem occurs on a widget level and results in the background being drawn partially black with garbage at its edges. The foreground (i.e. text etc.) is always rendered fine.

I can trigger the error when e.g. resizing a window or changing the focus (mine follows mouse) back and forth. It does not happen every time, but in about every 20th situation (average), sometimes more frequently.

As this occurs in exactly the same way with and without compiz enabled (which fundamentally determines how the screen is rendered - either via GL textures or via pixmaps) and with different drivers including nv, I would agree with last post and would think that the driver is NOT causing the error during hardware rendering but that the error is caused at some X-layer before (some timing-related issues when refreshing a widget's background).