I've just installed Ubuntu 12.04 on a Lenovo T440p. I have an integrated Intel GPU, which works fine (until now), and another gpu (NVIDIA GeForce 730M) which I wanted to use instead. I installed the drivers but I had the following problem: whenever I close the lid the laptop goes into sleep mode, but when I open the lid, the screen shows crap (it's not black, it has glitches) and it doesn't return normal. It's kind of annoying since one has to shut down the computer brutally. I also tried installing directly the drivers which one can download from the NVIDIA website, or doing everything on Ubuntu 13.10 but this doesn't change much.
Note that this only happens when I'm using the NVIDIA gpu. If I deactivate the driver for the NVIDIA, and use the intel instead, then the screen works fine, also after having reopened the lid after sleep mode. With Ubuntu 13.10 it's the same. I have read in some forums that some other users had the problem that they're screen went black after sleep mode, but I couldn't find any post about glitches, and I also tried the solutions for the black screen.
If there is a similar post, please delete this one, if not, I'd be happy to hear from someone that had the same problem or that has a clue about it! thanks, nico