And as it is now Linux-enabled laptops with two graphics cards?

In kernels >=34 included support for switchable graphics, on this subject, it is necessary to Google vga_switcheroo. Enough to have two one-line script to switch video and do not forget to restart the X server.
Overall are the owner of a laptop with 2 cards: one Intel, the second is ati 4650. The latest versions of Linux distributions start immediately. Yes, will have to abandon drivers from the vendor as is the case with AMD, and in the case of Nvidia.
About Nvidia, as I remember the nouveau developers have pledged their support for switchable graphics, I don't know how they have it now.

the latest Ubuntu, just experimenting — graphics i5 + GF 310M — not including the proprietary driver — all very good. after enabling the add — the system will not even boot... there may be a way out of ICU but I Blo it is easier to reinstall the Axle... in General, is still easier in Windows to sit while the driver will not run-in =(

Debian, Netbook Asus N10, 2 video cards — Intel and NVIDIA, found the manual and did it for video switching with native fire wood of the vendor, unfortunately it worked not very stable, so the demolished wood and left that came to distribe. Happy.