Isn't Wifi supposed to be off by default?

Werner Almesberger werner at
Thu Jan 15 20:09:45 CET 2009

Andy Green wrote:
> I agree there's no need for it, but is it true it won't consume anything
> at all when uninitialized?  It's still hooked up to 1.8V and 3.3V with
> no real off switch, so it will consume the odd picojoule or hundred or
> more entirely at the whim of the firmware.

Okay, and a few electrons will probably tunnel through some quantum
walls to ground out of sheer spite as well ;-)

But not loading the modules should be the next best thing to
physically removing the WLAN board, in terms of not burning power.

I'm doing some power consumption measurements of the various states
to make sure that nothing "leaks", so I hope I can put numbers to
the various levels of activation and tell whether it makes sense to
optimize by, say, holding the module in reset or not loading the
SDIO stack. (I don't expect either to make much of a difference, but
we'll see.)

Right now, my main problem is that I get a base consumption in
suspend with a "naked" userspace of about 145mA at 4.0V, with
noise/drift in the 1-2mA range. I can bring it down to ~100mA by
killing regulators and such, but there's still something big there
that shouldn't be. I just hope it's not the Glamo somehow escaping
suspend ...

- Werner

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