[Community-news] OLPC News (2008-02-09)

[david at lang.hm]

On Sun, 10 Feb 2008, Frank Ch. Eigler wrote:

> "Walter Bender" <walter at laptop.org> writes:
>
>> [...]
>> Chris Ball provided Richard with some power readings from our newly
>> enhanced power tinderbox running a C2 (mass production) laptop. [...]
>> The top auto-suspend power-draw breakdown:
>>
>> WLAN:	734 mW
>> backlight:	362 mW
>> memory:	239 mW
>> LCD:		218 mW
>> EC:		108 mW
>> other:		339 mW
>> total:		2064 mW
>> [...]
>> A next step will be to see if the wireless power can be reduced during
>> suspend. [...]
>
> Has the following idea already come up?  How about just turning off
> the wlan entirely during suspend, if the machine has reason to believe
> that its contribution to mesh connectivity is negligible?

what's the power draw of the WLAN chip if the transmitter is turned off?

the big problem with trying to have it off most of the time is the problem 
in syncing the wakeups (as discussed elsewhere in this thread), but it 
should take significantly less power if it's only receiving, and it could 
be on in receive mode a much larger percentage of the time and therefor 
have a much better chance of hearing another machine's broadcast.

David Lang