I have written a small D3D9 test app which shows this behavior: Compile it with "winemaker .", followed by make, and run it. Pressing ESC will cause it to quit, pressing any other keys makes IDirect3DDevice9::Clear call on the back buffer, with a color value based on the pressed keys. A click anywhere will LockRect() the whole backbuffer, write 0xff into the whole locked memory, and UnlockRect() it.
The screen should become completely white, but instead it goes black. With the fglrx driver and 24 bit color depth it shows the correct behavior, but with any other driver(radeon, software rendering) or 16 bit color depth, it doesn't work. The bug is somehow related to some GL calls in UnlockRect(glPixelZoom and glOrtho), but I couldn't find anything specific.
That program works fine for me with OpenGL vendor string: NVIDIA Corporation OpenGL renderer string: GeForce4 Ti 4400/AGP/3DNOW! OpenGL version string: 1.5.2 NVIDIA 66.29
Perhaps it's ATI specific? I wonder if you can reproduce it by calling the relevant OpenGL functions directly.