Magic SysRq Key

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Excerpt from Linux's Documentation/sysreq.txt:
What is the magic SysRq key?

It is a 'magical' key combo you can hit which the kernel will respond to regardless of whatever else it is doing, unless it is completely locked up.


  • Check it is enabled:
# cat /proc/sys/kernel/sysrq 

From Host serial console with Kermit

  • Send break character (Ctrl-\ b) then the key corresponding to the wanted action. For example to reset the board you will press:
Ctrl+AltGr+8 then b then b

From any terminal on the APF

  • Send the character to corresponding /proc interface. For example to reset the board:
# echo b > /proc/sysrq-trigger

From the LCD pseudo terminal with an USB keyboard

  • To Be Tested...