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Date:      Fri, 11 Oct 2002 15:37:53 -0500
From:      gordonb.uwu89@sneaky.lerctr.org (Gordon Burditt)
To:        freebsd-mobile@freebsd.org
Subject:   Re: Power
Message-ID:  <EH3U3Z5-0006NC-00@macwombat.iadfw.net>
In-Reply-To: <ans4f4$2dls$1@FreeBSD.csie.NCTU.edu.tw>

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>On Monday 07 October 2002 09:19 am, Pookie wrote:
>| How does FreeBSD handle itself when i disconnect the power plug on my
>| laptop? I'm not sure how this works. Can someone please direct me in
>| the proper direction?
>
>Why would FreeBSD have to "do" anything?

Maybe it doesn't HAVE to "do" anything, but I have found that on
my Sony VAIO PCG-FXA47 laptop it does.  It freezes up.

I'm running my laptop from AC power, but with a fully charged
battery.  A windstorm causes a brief (3-second) power outage.
FreeBSD has frozen.  It's very easy to reproduce this, although
there have been some times when a reproduction attempt failed.
The same thing does NOT happen with Windows XP.  With XP, the icon 
changes to a battery, but it keeps on running.

The 4.6.2-RELEASE kernel has APM compiled in and in use.
I've also tried later STABLE versions, no change.
Things like "shutdown -p" work.  Suspend (zzz) also sort of works
but dhclient ends up making tons of log entries, complaining about
wi0 going away, when it wakes up.

>Your laptop should handle it itself down in the hardware.
>
>If you have apm enabled, then FreeBSD's apm calls can *discover* that 
>the power is now coming from the battery rather than the plug, but the 
>operating system isn't called upon to *do* anything.

Are you sure that APM doesn't try to notify the OS that power has
gone, and FreeBSD doesn't know what to do with such notificaton?

>
>The proepr directions are to plug & unplug at will . . . if you want to 

Not with my laptop.

>monitor the status properly, enable apm in your kernel and in your 
>rc.conf.

					Gordon L. Burditt

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