Re: [PATCH] add acpi powerbutton support

[Jan Kiszka <jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ@public.gmane.org>]

Gerd Hoffmann wrote:
>   Hi,
> 
>>>> Catching ctrl-c sounds like a good idea but "ctrl-c, ctrl-c" should
>>>> probably kill qemu then, since the machine might have no acpid running -
>>>> in that case hitting ctrl-c would have no effect.
>>>>     
>>> Good idea.
>>>   
>> I'm worried about the 30+ second shutdown latency.  Is there precedent 
>> for SIGTERM or SIGINT requiring this long to take effect?
> 
> xenner signals a shutdown request to the guest for the first SIGINT (and
> prints a message to the user saying so).  Sending SIGINT twice kills the
> guest and cleans up.  I find that very useful, you can shutdown the
> guest cleanly with a convenient Ctrl-C and also kill it off quickly by
> simply pressing Ctrl-C again.

Yeah. After having worked with this feature for a few days (I'm mostly
running qemu/kvm from command line, w/ and w/o SDL GUI), I can only
underline the usefulness of it again.

> 
> SIGTERM kills the guest instantly.  Applictions are expected to react
> quickly on SIGTERM, there is no way you can wait for a clean guest
> shutdown then.  It is used on (host) shutdown for example, where you'll
> get a SIGKILL when you don't exit within three seconds.
> 

Ack, let's stick with SIGINT.

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

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