My Ubuntu 18.04 -whole system- freezes regurlary. It is a Dell Latitude 3510.

  • I tried the Alt+PrintScreen (5mp)+r+e+i+s+u+b (2 mp delay between keystrokes) and the same with Alt+Home at the start.
  • Also tried this two while holding down the Alt constantly.
  • My sysrq is enabled, cat proc/sys/kernel/sysrq showed a value 176 - what ever that means.
  • The only way to shut it down is to take out the integrated battery from the inside of the laptop.

Is there a way to find out which key "hides" my SysRq?

  • 3
    What's the laptop exactly? AFAIK the "magic combo" depends on the manufacturer, might change between models. Also what's "2 mp delay"? Commented Sep 13, 2021 at 18:55
  • 2
    If there is no key that says SysRq, then usually it's the PrtSc key.
    – undefined
    Commented Sep 13, 2021 at 19:26
  • For the meaning of 176 check this answer. Mine shows the same and it seems to stand for 128+32+16, which means the available functions are "reboot/power-off" (128), "read-only remounts" (32), and "sync" (16).
    – stafusa
    Commented Jan 3, 2023 at 13:28

1 Answer 1


The magic SysRq key is enabled when cat proc/sys/kernel/sysrq shows 1.

Use sudo sysctl kernel.sysrq=1 for the current session or set sysrq_always_enabled=1 as a kernel parameter to make the setting persist after a reboot.

The PrtSc is generally also the SysRq key. Just use Alt with PrtSc as normal. You can also try using AltGr in place of Alt.

See the troubleshooting part of this archwiki section for more troubleshooting tips if this does not work.

  • 4
    What if there is neither a SysRq nor a PrtSc key on my keyboard? :( Using a Logitech MX Keys Mechanical (no, the Snipping Tool key does not work).
    – Person
    Commented Jul 16, 2023 at 9:32

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