I'd like to clone the screen output to the tv for watching dvd, but it's not working out of the box with mandrake 10.1. It's however working fine in windows. so where does the problem lie? do i need to install drivers/other stuff to get this working, or is it just a matter of changing some values in a conf-file? i've googled this problem for days, but that only made me more uncertain where to start.

I have a ATI Radion card, if that makes any difference.