13

kwin occasionally hangs, which looks like the system not responding to mouse clicks or key presses - although the mouse pointer still moves when you move the mouse!

25

As described in the official Kwin documentation, a good way to go would be to try this either on a running terminal application or on a virtual console (i.e.: Ctrl+Alt+F1), :

DISPLAY=:0 kwin --replace
  • +1, possibly the same effect as my solution (does kwin respond properly to sigint?), and certainly not worse. Also, a single command, so better. – Sparhawk Oct 11 '13 at 1:34
  • Don't you want to run it in the background? – Piotr Dobrogost Feb 22 '14 at 21:26
  • 1
    Thank you, thank you. Thankfully it crashed on a terminal screen; this saved me a bunch of heartache. – Peter Klipfel Oct 12 '16 at 18:48
5

Similar to Robin Green's answer, but this does not require a terminal window to be open already. Instead, specify the display in which to start kwin from tty1. Hence,

Press Ctrl+Alt+F1 to access a terminal. Log in.

Type killall kwin. Then, type in DISPLAY=:0 kwin.

Press Ctrl+Alt+F7 to change back to your primary display.

  • Shouldn't kwin be run in the background? – Piotr Dobrogost Apr 29 '14 at 19:09
  • @PiotrDobrogost If you like. It's running from tty1, which I wouldn't really use anyway, so I don't find backgrounding kwin necessary. – Sparhawk Apr 29 '14 at 22:53
3

Press Ctrl+Alt+F1. Log in. Type killall kwin.

Press Ctrl+Alt+F7.

Quit all open applications until a terminal becomes visible. Hover the mouse over the terminal application. Type kwin &.

What's that, no terminal application open? Tough - you'll just have to reboot.

  • I just added an answer that starts kwin from tty1, but I wonder if there is another way (that doesn't require a terminal window to be open already). Presumably you are getting keyboard input back after killing kwin, so after switching back to tty7, can you not just press alt-f2 an run kwin from there? – Sparhawk Dec 27 '12 at 1:32
  • Also, my two suggestions mean that you don't have to leave a terminal window open. – Sparhawk Dec 27 '12 at 1:34
0

Just do:

killall plasma-desktop
plasma-desktop &

you could have it all in a bash script in case you need it more times,

recoverkde.sh:

killall plasma-desktop
plasma-desktop &
  • 1
    And how am I supposed to execute these commands if kwin won't let me do anything on the X display? – Robin Green Nov 7 '12 at 9:47
  • This restarts plasmashell but not kwin. I had the experience of frozen window that crushed kwin: restarting plasmashell would not fix this, but pkill kwin would. – user47206 Jul 12 '18 at 14:54
0

This actually works. It is a nasty bug but at least I can recover now.

In my case, there is no need to go back to the console login using ctrl+alt+f2 but using alt+f2 I can simply type killall plasma-desktop plasma-desktop and then using alt+f2 again,

I can run plasma-desktop. Could also be used in a script of course. This way I get back my mouse and I will not lose any work.

  • 1
    I think that is a slightly different bug, because as I said, I could not use the keyboard at all except to switch to a virtual console. I do mean literally kwin, not plasma-desktop. – Robin Green Nov 18 '12 at 17:23
  • This restarts plasmashell but not kwin. I had the experience of frozen window that crushed kwin: restarting plasmashell would not fix this, but pkill kwin would. – user47206 Jul 12 '18 at 14:54
0

In later Kubuntu/Plasma 5 kwin still hangs/crashes (especially with Intel display drivers it seems), but can be more easily restarted: just run in krunner - Alt-Space, or Alt-F2: kwin --replace


Or, create a new custom shortcut for that: e.g. Trigger: Meta+K, Action, Command/URL: kwin --replace.

In this way kwin can be restarted with just the Meta-K shortcut.

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