A user is reporting a black screen in our game on his Windows 8.1 system with a Radeon R7. The program is running, he can hear audio, but there are no graphics appearing at all. Even the clear colour (red) doesn't show up (black instead). A simple OpenGL sample is functioning correctly, and the render context, bit depth, SwapBuffers, etc. appear to be working as expected. He has completely uninstalled the drivers and reinstalled the latest, with no change.
It's very slow going debugging this without it happening for me. He doesn't have anything more specific than "R7 series", so I wouldn't know what to purchase for testing. Is there any service provided by AMD for testing compatibility with their video cards? I'm happy to provide Steam keys.