As I posted elsewhere, I have installed Ubuntu 18.04 alongside another Linux (dual-boot system). My computer has an AMD A12 processor with Radeon R7 graphics. I have installed the Oibaf driver, but that doesn't seem to improve anything.

I've been having a lot of problems with the Ubuntu installation. The problem I'd like to address right now is that about one out of three times when I close the lid on my laptop and go to open it again, I get a hash of colors and the screen is frozen and I can't log back into Ubuntu and have to forcefully turn it off without shutdown. I don't know if the computer itself is frozen because I have no way of getting past the frozen screen.

I also sometimes notice this hash when switching out of full screen mode in Totem, but thankfully the screen doesn't freeze.

This also can happen when the computer is awakened after sleep. This is intolerable to me because I can't afford to constantly be losing all my work every time this happens.

Any ideas?

I appreciate any help you can give.

This might be just an indication of a more general problem and the color hash might be misleading. This morning, the computer went to sleep because I closed the lid. When I opened the lid, the lock screen was blank. Totally blank. No hash, nothing. Again, this is unacceptable to me because I lost all my work again. I have set the computer not to sleep on lid close, but I really would like to find a solution and not just a workaround..

So I guess my question has to do with how to I remedy a computer not coming back from sleep?

I still believe that it is the screen that's frozen because I can hear the hard drive clicking.

I found the cause of this problem and other problems I've been having. Believe it or not, it was the video driver. The Linux drivers for AMD Radeon R7 graphics have problems. I installed the new driver for Ubuntu 18.04 (still beta) from AMD, and all my problems went away.

Interestingly, I did not have such problems with Scientific Linux (Enterprise Linux) and I didn't install any proprietary drivers so they are doing something right.

I thought I had the problem solved, but it raised it's ugly head again. This did work though