Ubuntu – Ubuntu 20.04 Everything freezes except for mouse pointer

20.04freeze

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?

Best Answer

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.

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