[Gta04-owner] 8mW sleep for Beagle Board

Radek Polak psonek2 at seznam.cz
Fri Jan 4 10:21:38 CET 2013

On Thursday, January 03, 2013 01:09:53 AM NeilBrown wrote:

> On Tue, 1 Jan 2013 16:29:45 +0100 Radek Polak <psonek2 at seznam.cz> wrote:
> > Hi,
> > i found this mail:
> > 
> > https://groups.google.com/forum/?fromgroups=#!topic/beagleboard/GXqO9rRsy
> > Cg
> > 
> > Do i count right? 8mW means 2mA on 4V battery. I wonder if we could apply
> > this also on GTA04.
> The first patch is a useful guide for writing similar code for the GTA04.
> The remainder aren't particularly relevant I think - the relevant
> functionality is already in mainline.

I wonder about the HW changes - if they can be also applied on GTA04.

> I've recently refreshed my understanding of the power-use situation and how
> to make some real progress on it soon.
> There are two parts that are needed.
> 1/ the OMAP3 SoC need to enter 'off-mode' during suspend.
> 2/ the twl4030 needs to turn various regulators off during off-mode.
> The patch patch in the post you linked addresses the 2nd point.

I have tried to uncomment your twl scripts, but it did no difference. But that 
was quite expected...

> You can get SoC to enter off-mode by compiling with PM_DEBUG=y, and
>  echo 1 > /sys/kernel/debug/omap/enable-off-mode
> (or some file name like that).
> One problem is that when you resume from off mode the USB ports don't work.
> This makes it hard to use the 3G modem for example.
> So we need to find out why USB doesn't work, and fix that.
> We also need to find out if off-mode breaks anything else.

I'll try to play with it during weekend.

Thanks a lot Neil for your pointers!

Btw i am running 3.7 kernel now for like week and no regression spotted yet. 
Great work!



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