bizarre timing, I've just spent the entire day moving my laptop to Debian XFCE, and the vast majority of that time was spent trying to get the bloody Nvidia card to work, which it won't because of Optimus, so that I can play with WebGl. Then I find out that it'll never work because any hybrid rig is excluded from WebGl (presumably because of Optimus randomly deciding that browsers don't need GPUs). And of course I can't disable the Intel graphics chipset from the BIOS. sigh