6.x acpi powerbutton
smithi at nimnet.asn.au
Fri Apr 17 19:21:49 UTC 2009
On Fri, 10 Apr 2009, Nate Lawson wrote:
> Andriy Gapon wrote:
> > on 09/04/2009 23:24 Stephen Clark said the following:
> >> Is there a reason it doesn't send and event like Linux that can be acted
> >> upon by user space other
> >> than signaling init? I like to have a message written in
> >> /var/log/messages that someone pressed
> >> the powerbutton.
> > I think that for all suspend states except S5 userland is notified via
> > devd mechanism and potentially can veto the suspend. S5 (soft-off) is
> > coded to start shutdown immediately. You can try to hack on
> > acpi_ReqSleepState in sys/dev/acpica/acpi.c.
> > I am not sure what is the reason for this special behavior of S5. But I
> > like it, because it sometimes allows me to perform semi-clean shutdown
> > when X goes crazy. But I also see when it could be useful to have S5
> > request go through userland. So this could be configurable.
> The reason for userland getting into the loop in the first place was to
> run programs to shut down devices and reinit them after resume. This
> isn't necessary in the shutdown case because init already sends a
> signal, as you mention.
> There's already a mechanism for timing out if userland is not
> responding, so a suspend will ultimately happen whether or not it
> answers. However, that waits for a while (1 minute?) and devd used to be
> optional, so I thought it best to keep the existing S5 behavior
> (immediate shutdown).
> It may be ok to enable this for S5 but I don't think it's very useful.
Perhaps a silly question, but is it too late at this stage of the game
to try logging S5 events to syslog before dying? I agree with Stephen,
logging 'shutdown by powerbutton' surely beats what might otherwise
resemble a spontaneous reboot? Or is something already logged here?
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