I had the same issue again today. Black external screen and black internal screen after logging into the Gnome Wayland session on my laptop with AMD graphics. To turn on my screens, i have to press Ctrl+F3 and then Ctrl+F2. But the issue does not happen on every boot.
- Bug#1125275: mutter: Black screen on an HDMI monitor aft... Nazik
- Bug#1125275: Nazarii Kretovych
- Bug#1125275: (no subject) krmzr . accs
- Bug#1125275: Additional info for 1125275 Nazarii Kretovych
- Bug#1125275: mutter: Black screen on an HDMI monito... Simon McVittie
- Bug#1125275: mutter: Black screen on an HDMI mo... Nazarii Kretovych
- Bug#1125275: mutter: Black screen on an HDM... Simon McVittie
- Bug#1125275: mutter: Black screen on an... Nazarii Kretovych
- Bug#1125275: mutter: Black screen ... Simon McVittie
- Bug#1125275: mutter: Black scr... Nazarii Kretovych

