I am new to Linux and having a very difficult time running Elementary OS Loki. I am currently running it on a 2011 Macbook Pro with an AMD Radeon GPU as well as an integrated Intel GPU. I want to disable the AMD GPU but cannot figure out how. I have searched for several hours and have not solved my problem. Currently I have "nomodeset" written before "quiet splash" in grub in order to be able to use the laptop. To my knowledge, both graphics cards are still operating. If I do not have "nomodeset" written in, upon booting the screen will remain black. Like I said, I am new and have searched for several hours and this is as far as I have been able to come. I have tried many different methods and am still lost. Thank you for any help.