problems with thinkpad w520 discrete graphics + CPU VT options on

In order to use the displayport video port, the machine has to boot with discrete graphics turned on in the bios
there's a problem with the stock Nvidia drivers for the w520's discrete graphics card and Intel's VT-x VT-d virtualization CPU settings
[x] try out the ppa suggested to get the latest Nvidia drivers

sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current

this didn't work -- the ppa isn't available for 15.10
[x] install the latest nvidia binary from another source
- google turned up this article on grabbing the latest Nvidia drivers for 15.10

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update && sudo apt-get install nvidia-355

sudo apt-cache search nvidia

which turned up a listing for nvidia-358 -- so that's the one I'm installing
[x] does this allow me to run discrete graphics and intel VT-* CPU options?
- with the nvidia-358 driver loaded, I'm able to boot even with Intel's VT-x and VT-d CPU options enabled
[ ] is there a way to software toggle which video adapter drives that machine? (it would be awesome to be able to save battery by switching to integrated graphics without having to reboot the machine)
- on 2011 macbook air (and later models) both Intel graphics (that shares system memory) and discrete graphics are available to the OS without BIOS config. (I only think this because there is no "BIOS" on a mac that you can boot into to make system changes like you can on traditional PCs)

ruebenramirez / blog