[Gta04-owner] Modem off

Andreas Kemnade andreas at kemnade.info
Mon Nov 11 16:38:31 CET 2013


Hi,

On Sat, 2013-11-09 at 15:12 +1100, NeilBrown wrote: 
> On Fri, 8 Nov 2013 15:49:50 +0100 Andreas Kemnade <andreas at kemnade.info>
> wrote:
> 
> > On Fri, 8 Nov 2013 14:07:13 +1100
> > NeilBrown <neilb at suse.de> wrote:
> > 
> > > On Tue, 5 Nov 2013 15:02:34 +0100 Andreas Kemnade <andreas at kemnade.info>
> > > wrote:
> > > 
> > > > Hi,
> > > > 
> > > > On Tue, 5 Nov 2013 08:51:26 +0100
> > > > Radek Polak <psonek2 at seznam.cz> wrote:
> > > > 
> > > > > On Monday, November 04, 2013 11:09:27 PM Andreas Kemnade wrote:
> > > > > > Hi,
> > > > > > 
> > > > > > On Sat, 2013-09-21 at 08:19 +1000, NeilBrown wrote:
> > > > > > > I've experimented with "rmmod ehci_hcd" just before suspend, and
> > > > > > > "modprobe" on resume, but so far that has just caused a mess.
> > > > > > > I've looked at the code, and it is rather complex.
> > > > > > > It has also changed a lot in 3.10.  So I'm going to defer exploring this
> > > > > > > more until I start on 3.10+ again, probably in a couple of weeks.
> > > > > > 
> > > > > > In 3.12 I get also around 15mA more current in suspend with modem off.
> > > > > > than with modem on. (suspend does not work reliable with that kernel for
> > > > > > me and I have 60mA/85mA current consumption)
> > > > > > 
> > > > > > In 3.7 with enabled modem
> > > > > > doing "echo ehci-omap.0 >unbind" in
> > > > > > /sys/bus/platform/drivers/ehci-omap
> > > > > > also increases current. (I get 40mA then)
> > > > > > doing "echo echi-omap.0 >bind"
> > > > > > decreases it again to around 20mA.
> > > > > > That is also strange.
> > > > > > 
> > > > btw: what is different in doing rmmod/modprobe and doing the unbind/bind?
> > > 
> > > There should be no difference.
> > > Both 'modprobe' and 'bind' will run the 'probe' function of the driver.
> > > Both 'rmmod' and 'unbind' will run the 'remove' function.
> > > 
> > 
> > Hmm, there might be a difference. The order of things being called is
> > different. If we use unbind/bind
> > and have ehci-hcd compiled in, the probe function is called earlier. 
> > > [...]
> > > This is at least very clear evidence that the USB port together with the
> > > transceiver account for a substantial portion of the power usage.
> > > 
> > > Figuring out why and fixing it is a somewhat different story....
> > > 
> > Hmm, that is taming another usb phy. Should it be more difficult than
> > the otg one? I think I know what I will do the next days...
> > 
> 
> I look forward to hearing of your results.

At the moment I even cannot reproduce your the lower currents when the
module is removed or unbind is done (when the modem does not show up on
the bus). I measured current_now directly after suspend and retried also
with that 5-min average using charge_now.

> Meanwhile, here is a result that turned out more effective than I expected....
> 
> I've automated some parts of my power-usage-monitoring a bit more.  With my
> phone running normally with USB enabled etc with my current 3.7 kernel, the
> average-current-over-5-minutes frequency histogram looks like:
> 
does this mean, modem shows up on the usb bus during the tests?

Greetings
Andreas Kemnade



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