[RFC PATCH] libertas: turn radio off when down

[Dan Williams]

On Wed, 2007-11-21 at 02:06 -0500, Chris Ball wrote:
> Hi Dan,
> 
>    > Last I knew there were cases where mesh forwarding was _not_
>    > supposed to be on due to the high power drain of the 8388 when the
>    > radio was enabled, plus the airplane case.  As long as the
>    > networking core doesn't close the devices on suspend, this patch
>    > shouldn't have side-effects on mesh forwarding.
> 
> The current setup is:
> 
> suspend:  caused by idleness, radio stays on, unicast wakeups stay on

This implies that the device is not downed, since unicast wakeups would
be useless if the device wasn't receiving.

> sleep:  caused by lid close or power button, radio stays on, wakeups off

This case could be the one that kills the patch if it's anticipated this
state would last more than some number of minutes (10 or 20 maybe?).

> I think it's still undecided whether sleep should leave the radio on or
> not -- we need to take power measurements now that mesh beacons can be
> disabled and see whether the power consumption is significantly reduced.

That would be quite interesting to see, yes.

>    > [1] when doing long suspends, when the resume occurs userspace will
>    > need to redo the networking setup anyway, scanning and searching
>    > for the school server or default mesh channel, because a long
>    > suspend most likely means you changed location and increases the
>    > likelihood that the networking situation around you changed as
>    > well.
> 
> Is there a dbus message OHM can pass to NM for this?  (If not, maybe
> you could mention which NM functions perform the full scan/search so
> that we can wrap them?)

Well, basically sleep & wake will be what you want here.  That's the
normal path on regular laptops when suspend/hibernate is used, and will
cause NM to down all devices.

If ohm is doing the intelligent power control stuff here, then it could
certainly be the thing that tells NM to go to sleep and turn off the
radios.

Dan