kern/73823: [request] acpi / power-on by timer support

[Kostik Belousov]

On Mon, Sep 06, 2010 at 07:20:17AM +0000, Andriy Gapon wrote:
> The following reply was made to PR kern/73823; it has been noted by GNATS.
> 
> From: Andriy Gapon <avg at icyb.net.ua>
> To: AW <arne_woerner at yahoo.com>
> Cc: bug-followup at FreeBSD.org, Bruce Cran <brucec at FreeBSD.org>
> Subject: Re: kern/73823: [request] acpi / power-on by timer support
> Date: Mon, 06 Sep 2010 10:14:45 +0300
> 
>  on 06/09/2010 09:54 AW said the following:
>  >> Can someone (Bruce?) explain to me in greater detail what this PR is about?
>  >>
>  > I believed that the box can boot at the specified time if Linux powers it down...
>  > and that it cant, if FreeBSD does it...
>  > 
>  >> I thought that the functionality of turning power on at certain time completely
>  >> belonged to BIOS.  How is acpi(4) driver expected to help?
>  >>
>  > i dont know... maybe the power down procedure offers some flag
>  > (like "power down, but honor the BIOS settings about wake-up time" and
>  > "power down and ignore BIOS settings about wake-up time")?
>  > That LAN wake-up packet worked fine (WOL?) if FreeBSD powered the box down...
>  > 
>  > Maybe i used a different/buggy BIOS when I found the problem?
>  > Maybe Linux couldnt do it, too...?
>  > 
>  > I dont use that box (mainboard: ECS K7VVM+ or so)/FreeBSD anymore,
>  > but it should be easy for u to test it on contemporary hardware...
>  
>  Well, I am not aware of any OS assistance or control over this.
>  If hardware and BIOS support this feature and it is properly configured, then
>  power-on happens entirely in hardware and for OS it looks just like a normal boot.
>  
>  BTW, an interesting page:
>  http://www.mythtv.org/wiki/ACPI_Wakeup
>  It mentions that BIOS would disable wake up if hardware clock is modified later.
>  We do that.

I think this is RTC wakeup event support. See, for instance,
4.7.2.4 Real Time Clock Alarm in ACPI 4.0 spec.
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