Subject: Re: power management and related concerns
To: Jason Thorpe <>
From: Garrett D'Amore <>
List: tech-kern
Date: 07/05/2006 11:29:11
Jason Thorpe wrote:
> On Jun 30, 2006, at 5:28 PM, Garrett D'Amore wrote:
>> 1) there doesn't seem a clear way to indicate powerfail for a low
>> battery condition in sysmon.  Should I just be sending init some signal?
> You should add this capability to sysmon :-)  powerd(8) can then
> handle the message.
>> 3) Currently it isn't clear whether you should be registering with APM,
>> sysmon, or something else for things like battery status, etc.  It would
>> be really, really good if drivers didn't have to do _both_ of these
>> things.  Can we maybe have a sysmon APM compatibility layer?  (I guess
>> there are some userland apps that "know" about APM.  Bletch.)
> BACKWARDS!  sysmon is where things should be going.  The whole idea is
> that sysmon is a generic system that has back-ends for APM, ACPI,
> etc.  Right now, sysmon is just a skeleton, but it has some pieces
> there that e.g. ACPI is using now.
>> 4) We need some userland tools to talk to sysmon in base, I think.
>> (E.g. to query batteries, etc.)
>> 5) In many respects, sysmon looks like a good start.  I've coded a quick
>> power management driver for the Ultrabook IIi (okay, it was mostly a
>> port from Solaris), and it basically works for things like lid switch,
>> AC power cord un/plug, and power button.
> Yah, that was the whole idea :-)
> -- thorpej

So should I be extending sysmon then?  Who wants to review my

I'm inclined to switch the event notification to userland from fixed
ioctls to property lists.

    -- Garrett

Garrett D'Amore, Principal Software Engineer
Tadpole Computer / Computing Technologies Division,
General Dynamics C4 Systems
Phone: 951 325-2134  Fax: 951 325-2191