There is a error with the ATI driver with OpenGL and GLSL.
When you call the function
vec4 tex = texture(textureSampler, textureCoord ) in the fragment shader,
its automatic discard every face wish dont have texture in it, even if you dont use this vec4 return anywhere.
its work fine in any Nvidia Card...
Radeon HD 6870
Windows 8 64 bits or Ubuntu 64 bits
Last one, version 13.4