I've installed Linux Mint 18 on my machine, but it has a Radeon HD Graphics card, which is not supported by AMD on systems based on Ubuntu 16.04 (according to some research I did).So, after the install the system was booting into a black screen and wouldn't go anywhere.I did some research and found that I could edit the grub boot commands and add radeon.modeset=0. That worked, but I don't know what that does.Is it ok to run permanently with this parameters?Does this lower my overall machine performance? I don't really care about graphics, I just use my machine to ordinary stuff.Thanks, guys.
Linux Mint with radeon.modeset=0
linux mint;radeon;proprietary drivers
The xxx.modeset=0 disables kernel mode setting for the hardware. In other words, this option tells Linux not to try activating and using the incompatible hardware, which is likely the source of your problems. When this is used, your  computer will still be functional, but without the benefits of hardware acceleration provided by the graphics card. This will only affect you when you use graphics-intensive programs such as complex, high-end games. Otherwise it's just fine.