My computer has a problem where occasionally it will become completely unresponsive. (Mouse cursor doesn’t move. Keys have no apparently effect. Whatever app is running freezes. I think its a hardware problem with the graphics card, but I don’t know what. Logs at the time it freezes say “the GPU has fallen off the bus”.)
Anyway… I recently learnt about Magic SysRq. And I’ve been able to shutdown the computer from this unresponsive state with SysRq, R E I S U O. Where as I understand it, the “E” tells processes the end nicely if they can; and then the “I” just ends them by force.
(At this point, I’m realising that the E is SIGTERM, not SIGINT - so that screws up the relevance of my story; but I figure I’ll keep going anyway.)
The point is, I’ve been using key combo with a nice pause between each key, thinking there was some chance that processes might be ending gracefully. But when I tried it while the computer wasn’t frozen, the computer was able to inform me that the E and I commands were disabled. (I don’t know why.) So even though I wanted to give a nice “please end” signal, in the end that just wasn’t happening.
Have you tried other TTYs? When I press Ctrl+Alt+F3, for example, I switch to a ‘real’ terminal that (I assume) doesn’t require the GPU to work. From there you might be able to recover.
On Linux Mint the default, graphical userface is on TTY7 (CTRL+Alt+F7).
Yes, I have tried that. But it has no apparent effect when the computer is in that frozen state. (i.e. pressing ctrl+alt+F3 or whatever doesn’t change what is on the screen.
One time I tried imagining that the terminal came up, and so I ‘signed in’ and tried to shut down without seeing anything on the screen. But it didn’t work. … but since I couldn’t see anything, it’s quite possible I just mistyped something. So I guess that’s inconclusive.
My computer has a problem where occasionally it will become completely unresponsive. (Mouse cursor doesn’t move. Keys have no apparently effect. Whatever app is running freezes. I think its a hardware problem with the graphics card, but I don’t know what. Logs at the time it freezes say “the GPU has fallen off the bus”.)
Anyway… I recently learnt about Magic SysRq. And I’ve been able to shutdown the computer from this unresponsive state with
SysRq, R E I S U O. Where as I understand it, the “E” tells processes the end nicely if they can; and then the “I” just ends them by force.(At this point, I’m realising that the
Eis SIGTERM, not SIGINT - so that screws up the relevance of my story; but I figure I’ll keep going anyway.)The point is, I’ve been using key combo with a nice pause between each key, thinking there was some chance that processes might be ending gracefully. But when I tried it while the computer wasn’t frozen, the computer was able to inform me that the E and I commands were disabled. (I don’t know why.) So even though I wanted to give a nice “please end” signal, in the end that just wasn’t happening.
Have you tried other TTYs? When I press Ctrl+Alt+F3, for example, I switch to a ‘real’ terminal that (I assume) doesn’t require the GPU to work. From there you might be able to recover.
On Linux Mint the default, graphical userface is on TTY7 (CTRL+Alt+F7).
Yes, I have tried that. But it has no apparent effect when the computer is in that frozen state. (i.e. pressing ctrl+alt+F3 or whatever doesn’t change what is on the screen.
One time I tried imagining that the terminal came up, and so I ‘signed in’ and tried to shut down without seeing anything on the screen. But it didn’t work. … but since I couldn’t see anything, it’s quite possible I just mistyped something. So I guess that’s inconclusive.
You could try enabling systemd-oomd. It’s a userspace OOM killer and seems to be aggressive enough to mostly stop that from happening.