Painting the Bump map does not work in Texture Painting mode. I can see the normals I painted just after rendering, but not in 3D view. For my bump map texture I enabled Geometry Normal and disabled Diffuse Color, but still no bumps in preview. Does anyone got an idea how I can got bumps in 3D preview?
You need to switch the viewport shading to Texture, or press AltZ in 3D View.
There are generally five things that you should keep in mind to make sure bump effect can be previewed in the 3D Viewport, as shown below:
Regarding that, you just missed the 4th one. :)