[gentoo-user] Video Out on laptop

I have an HP Pavilion Entertainment Laptop which has a video out port.  I want to hook up a projector or monitor to it, but when I do there isn't a signal.  There is a function key that is suppose to turn it on and off, but it doesn't seem to work.  Is this a kernel setting?It's an AMD Athlon 64 Neo X2 Dual Core Processor L335 running a current updated Gentoo system with kernel 3.1.6.Thanks,dhk