My geometry shader has no effect when the input primitive is GL_POINTS. I have to feed the geometry shader with one GL_LINES primitive, repeating the first vertex.
See the message here for more details:
I have the latest drivers are installed
ATI Mobility Radeon HD5470
Windows 7 x64
Catalyst Version: 10.8
Driver Packaging Version: 8.762.100803a-103697C-ATI
OpenGL Version: 220.127.116.1151