Ubuntu 20.04 Everything freezes except for mouse pointer

Computer worked fine for a couple of weeks.

Hardware specs:

• CPU: AMD Ryzen 9 3900X 12core
• Memory: 64GB Corsair
• GPU: Sapphire Radeon RX 5500 XT NITRO+ 8GB
• Motherboard: ASUS ROG Strix X570-F GAMING
• Wireless keyboard and mouse
• monitor: 4K 60Hz

Problem: Computer freezes. It freeze most frequently when watching video in browser, after a while sound stops, a few seconds later computer is in this state:

• I can move the mouse-cursor, but clicking does nothing.
• Ctrl + Alt + F1 does nothing
• Short pressing the power button does nothing
• Picture is frozen except for the mouse cursor moving
• Same problem when connecting another keyboard and mouse
• SysRq REISUB works

Debugging different resolutions:

• No Problems: Resolution 1920 x 1080, Refresh rate: 60Hz Scale: 100%
• Fails: Resolution 3840 x 2160, Refresh rate: 60Hz Scale: 100%
• Fails: Resolution 3840 x 2160, Refresh rate: 60Hz Scale: 125%
• Fails: Resolution 3840 x 2160, Refresh rate: 60Hz Scale: 150%
• Fails: Resolution 3200 x 1800, Refresh rate: 60Hz Scale: 100%
• Fails: Resolution 2560 x 1440, Refresh rate: 60Hz Scale: 100%

Debugging:

• htop: CPU is below 10%
• watch sensors: CPU heat is around 50C, CPU power consumption is about 5-10W
• tail -f /var/log/{messages,kernel,dmesg,syslog}: didn't give any messages that looked interesting, last error before crashing was some DNS stuff.

Does anyone have a suggestion how to debug this problem?

In /etc/profile, I would add this: setxkbmap -option terminate:ctrl_alt_bksp

Then, logout and login.

The next time you freeze, you can try entering Ctrl-Alt-Backspace to restart the desktop instead of having to reboot. In addition to getting you back to business faster, it tells you that X is still alive during a freeze. Not sure why "ctrl + alt + F1 does nothing".

A similar situation is also a current challenge for me on a Raspberry Pi 4 8GB with the Xubuntu desktop.

Good luck with a resolution.

Running xset s off in a terminal window before it freezes seems to help.

When the error occurred, I recognized a lot of messages like beneath in /var/log/Xorg.0.log

(II) event4  - Video Bus: device removed
(II) event1  - Power Button: device removed
(II) event9  - Keyboard: device removed
(II) event5  - Mouse: device removed

My computer haven't frozen since I upgraded to Ubuntu 20.10