Kubuntu 14.04 on a new computer. GPU is R9 280x in case it's relevant.
Sometimes (not every time) when I restart in order to switch to Windows, Kubuntu seems to hang. There's a black screen. I am able to change to
Ctrl+Alt+F1 and get a login prompt, but I can't do anything with it (the keyboard is not responsive). So I cannot inspect the state of the machine (processes etc.) when this happens. Pressing
Ctrl+Alt+F7 again I continue to see the tty1 login prompt, but it seems to be just painted remains (no blinking cursor).
Following answers to similar questions, I tried REISUB (with a few seconds after each letter), but it only prints some messages about USB devices to tty1, and nothing else. In particular, it does not reboot the machine, the only thing that seems to work is a hard reset.
I do not see any information from the relevant time in
rsyslogd: [...] exiting on signal 15.
How can I troubleshoot this problem?
Edit - more information:
- I initially tried only rebooting from the menu, but the problem also happens with
sudo shutdown -r now.
- The physical power buttons work as expected.
Ctrl+Alt+Del/Deletedoes not do anything in the hung state.
I have not reproduced the problem when halting instead of restarting.The problem happens when halting as well.
- My system is up to date.
- I waited a few minutes in the hung state before trying REISUB in tty1. Some new information appeared, I took a picture. Everything between "INFO" until the end of the call trace wasn't there before, I guess it only appears if you wait. This time,
- Removing the module 8192cu seems to work. However, it is my wifi card driver, so I need it. I have TP link 822n card. It works out of the box on Ubuntu, but disconnects after a while, so I had to follow this guide.