Isn't Wifi supposed to be off by default?

Andy Green andy at
Thu Jan 15 20:15:57 CET 2009

Hash: SHA1

Somebody in the thread at some point said:
| 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'd think so too but we don't actually know it -->

| 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.)

That'd be worthwhile, great.  I think someone looked at this in .tw
about a year ago but I never really read about what they found.

| 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 ...

Glamo is also permanently powered anyway, but it doesn't take 145 mA :-)

I would guess it is either WLAN or GSM, maybe pop the SIM if it is still
in there.

Balaji had auditing regulators that were still up on his list.

- -Andy
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