Screen looks shattered after upgrade to 20.04

Dear all,

today I finally decided to upgrade from 18.04 to 20.04. Now the screen looks as it was shattered in about 5 or 6 orizontal bands, and each band slided some inches to the right. I wish I could show you a screenshot, however the screenshots look normally, so I can only try to describe how it looks. The upper portion of the screen is ok, the band below looks like it slided a bit to the right, and the portion which slided out of the screen appeared on the left, the band below that slided even more, and so on. The mouse cursor moves in this shattered space, but do not act accordingly, meaning that, when I click, it looks like I'm clicking on the screen as it was not shattered.

During the installation I got an error message saying that it was impossile to install the GRUB on dev/sda1. I'm in dual boot and sda1 is occupied by windows. I got this error twice, and the only thing that I could do was to abort the installation or continue. I decided to continue, but now I don't have any issue at launch and the grub screen appears properly.

In case it matters in any way, I'm on a Acer Aspire 3 (A315-41) with an AMD Ryzen 5 2500U processor and a Radeon Vega graphic processor.

The fact that the mouse works as if nothing happened and the screenshot tool saves images that look fine makes me think that the problem is on a very high level of visualization, and I guess that the issue pertains to Mate, rather than Ubuntu.

Thanks in advance to anyone who will answer.

A post was merged into an existing topic: 20.04 Display issues with AMD GPU