Re: Soft reboot

[Philippe Hermoso <philippe@iea.mine.nu>]

Quoting Charles Plessy <charles.plessy@evc.net>:
> 
> Merci, mais dans mon cas quand X est planté (la dernière fois suite à
> de mulitples aller-retours entre consoles virtuelles), le clavier
> l'est aussi!
> D'où mon intér^et pour les boutons en facade de mon bo^itier...
> 
> Charles
je cite :

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

*  How do I enable the magic SysRQ key?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You need to say yes to 'Magic SysRq key (CONFIG_MAGIC_SYSRQ)' when
configuring the kernel. This option is only available it 2.1.x or later
kernels.

*  How do I use the magic SysRQ key?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
On x86   - You press the key combo 'ALT-SysRQ-<command key>'. Note - Some
         (older?) may not have a key labeled 'SysRQ'. The 'SysRQ' key is
          also known as the 'Print Screen' key.


*  What are the 'command' keys?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
'r'     - Turns off keyboard raw mode and sets it to XLATE.

'k'     - Kills all programs on the current virtual console.

'b'     - Will immediately reboot the system without syncing or unmounting
          your disks.


*  Okay, so what can I use them for?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Well, un'R'aw is very handy when your X server or a svgalib program crashes.
                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^       
sa'K' (system attention key) is useful when you want to exit a program
that will not let you switch consoles. (For example, X or a svgalib program.)

re'B'oot is good when you're unable to shut down. But you should also 'S'ync
and 'U'mount first.

plus d'info dans /usr/src/kernel-sources-X.X.X/Documentations/sysrq.txt




-- 
Philippe