Re: Add NULL power handler to x86/ipmi(4)

[David Young <dyoung%pobox.com@localhost>]

On Fri, Jul 16, 2010 at 06:14:39PM -0700, Paul Goyette wrote:
> On Fri, 16 Jul 2010, David Young wrote:
> 
> >On Fri, Jul 16, 2010 at 04:43:02PM -0700, Paul Goyette wrote:
> >>Is there any reason anyone can think of to not add a NULL power
> >>handler to the ipmi(4) driver?  I can't see any reason for anything
> >>special to happen either at suspend or resume, and the lack of a
> >>power handler prevents the system from going to sleep at all.
> >
> >ipmi(4) should probably not suspend if its watchdog timer is active.
> 
> Would it be sufficient for ipmi(4) to refuse to suspend (return
> false from the suspend method) if the watchdog is active?

Yes.  I think that's the right thing to do for now.

> Or should it make some sort of effort to disable the watchdog, and
> attempt to reenable the watchdog during the subsequent resume?

That defeats the purpose of a watchdog timer, at least for my purposes.
This is a local policy choice that should probably not be hard-coded.
Maybe we need additional watchdog modes?

1 Watchdog countdown stops during suspension, restarts after
2 Watchdog keeps counting down during suspend (we'll wake periodically
  to tickle it)
3 Watchdog prevents suspension

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933