I use a debian 9 with Magic Sys Keys enabled :

sysctl -a | grep sysrq
kernel.sysrq = 1

if I trigger in CLI, it works :

echo f > /proc/sysrq-trigger

I have something like :

emergency sync trigerred

from tty1.

But when I try to do alt+Print/Syst+s from tty1, I switch from tty1 to xorg tty7 with in xorg log :

[  1019.608] (II) AIGLX: Suspending AIGLX clients for VT switch
[  1044.548] (II) AIGLX: Resuming AIGLX clients after VT switch

Kernel :

$ uname -r

I use xfce4 4.12.3

No keyboard shortcut with this combo in xfce4 applications menu -> parameters -> keyboard -> keyboard shortcuts (translated from my mind French to English)

I tried with a fresh new user and it's the same problem.

I tried with no xfce4 session, just tty1 and lxdm on tty7, I still switch to lxdm tty7 if I type the keyboard shortcut

Any clue ?

EDIT 20180802

Same thing with cinnamon DM 3.2.7, if I hit alt+Print/Syst+s from tty1, I switch from tty1 to xorg tty

  • Did you forget the <kbd>ctrl</kbd> in the key sequence? However I believe the MagicSysReq key sequences don't work from X because of the way X handles the keyboard. – wurtel Jun 6 '18 at 12:00
  • No, I don't type ctrl, just alt+sys+s (French keyboard) – Gilles Quenot Jun 6 '18 at 12:36
  • I saw that that's only alt+sys+s that moves tty1 to tty7, alt+sys+f works, but now I can't write buffers to disk when I trigger oom-killer – Gilles Quenot Jun 13 '18 at 9:50
  • From my Debian-unstable system, Alt+Sys+S gives an Emergency Sync message in the syslog, even if I do it from X (the kernel sees keypresses before X does). It might have something to do with your hardware. Is this a VM? Is it a standard keyboard layout, or a minimal layout with a Fn key (or better yet, can you share an image?) You mentioned it's a French keyboard; are you using (left) Alt, or (right) Alt-Gr? Does "hold Alt, press Sys, release Sys, press S, release S, release Alt" work? – Jander Aug 7 '18 at 23:11

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