Re: Prevent auto scan in wireless devices

[Tony Espy <espy canonical com>]

Aloisio Almeida wrote:
> Hi all,
>
> I noticed that wireless devices are always scanning, and this is very
> bad to power consuption in embedded systems.

Having looked at Wi-Fi power consumption last year while working on a 
MID project, we did some measurements with a Marvell SD8686 card and 
found that backing off the scanning didnd't really save all that much 
power compared to when the device was associated with an AP and PS-Mode 
was enabled.

This led us to the conclusion that the only way to really save power 
while unassociated ( at least with the SD8686 ) was to toggle the power 
to the card when NM was in it's inactive phase ( ie. not associated, and 
not currently scanning ).

I haven't looked to closely at NM 0.7 to see how applicable this 
approach is, but if I get some time, I'll try and do so...

> Any comments? Is it a good way to implement that?

In the past, Dan has stated that he's against making scanning directly 
controllable via DBUS.

Ciao,
/tony