[Gta04-owner] Modem off

Radek Polak psonek2 at seznam.cz
Fri Sep 20 15:00:28 CEST 2013


On Thursday, September 19, 2013 03:47:47 AM NeilBrown wrote:

> I have some more evidence.
> 
> I currently have ehci_hcd compiled as a module, so it needs to be loaded
> before the modem can be seen.
> 
> On a fresh reboot of 3.7 without loading the module or toggling the GPIO to
> turn on the 3G modem, I see a current draw during suspend of 21.6mA and
> 23.7mA If I then "insmod ehci_hcd" the suspend-time current usage goes up
> to  30.1mA and 32.2mA.
> I then "rmmod ehci_hcd" and the current drops to 12.9 and 15.1 mA.
> 
> So in each case I see two different measurements with a 2.1mA difference.
> 
> Loading the module turns something on which was only partly one before.
> Removing the module turns it off properly.
> 
> If I can get "suspend" to turn off whatever "rmmod" turns off, we might be
> able to get power usage down by several milliAmps.
> 
> If anyone else would like to try this and report the results I would love
> to hear them.
> You need to set:
> 
> CONFIG_USB_EHCI_HCD=m
> 
> in .config and make sure nothing turns the modem on at boot time.
> Then measure the suspend current.  Then insmod and measure it again.  Then
> rmmod and measure it a third time.

Hi,
i have tested it today. I used qtmoko v55 kernel - the one which has enabled 
omap off mode.

Attached is screenshot with graph.

First current is 22mA - after boot.
Then there are values 31mA and 32mA - with ehci_hcd module loaded
The last values are 16mA 15mA and 15mA - after rmmod ehci_hcd

So i think we have quite similar results.

Regards

Radek
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