[Community] GTA04A5 / Letux 2804

Rico Rommel rico at bierrommel.de
Thu Jan 16 18:01:41 CET 2014

Am Donnerstag, 16. Januar 2014, 12:08:07 schrieb Dr. H. Nikolaus Schaller:
> Am 16.01.2014 um 11:42 schrieb Radek Polak:
> > On Thursday, January 16, 2014 11:21:39 AM Dr. H. Nikolaus Schaller wrote:
> > > Ok, please help to fix the power management (in the latest kernel
> > > because
> > > everything else makes no sense to me and is unlikely to get outside
> > > support).
> > 
> > I dont know how good/bad is PM in 3.12 kernel. But IIRC last time it was
> > much worse then 3.7. So the starting point could be to compare 3.7 and
> > 3.12 and get the PM to the level it is in 3.7.
> Hm. I think the starting point should be to check if your assumption that
> 3.12 is worse is still correct with the 3.12.7 kernel. Also because in the
> 3.12.7 kernel we have included all the 3.7 kernel patches.
> There are three potential reasons:
> a) at the time you tested there might have been a kernel bug, that may have
> been fixed by now (or may be still be open) b) we may have damaged one of
> the 3.7 improvements while merging/rebasing c) someone (in the Linux kernel
> community) has rewritten a kernel driver that we use and that now draws
> more mA.
> Most likely it is a single subsystem that does not work correctly any more.
> But without testing we will never know if it is really worse.

I think, it's even worse than Radek says.

Last Weekend i played around with kernel 3.12.7 and did a trip to make some 
GPS-tracks. It started with approximately 200 mA and increased within 3 hours 
to > 400 mA. The increase is also be observed with kernel 3.7, but not in this 

Btw, after copying the modules to the phone, i forgot to build the module-
deps, so no modules were loaded at boot time. Power consumption was < 100 mA 
in idle with display on. After loading modules and restarting fso-daemons, 
current increased to > 200 mA.

It was  reproducable multiple times after removing battery before powering on.

While starting fsodeviced + fsousaged is powering devices on and off, so 
something seems to not power down correctly.

Another problem is the camera driver. if it's loaded cpu doesn't enter higher 

It was already mentioned here:

There was a userspace problem, but I have no application, which is accessing 
the camera.

Another difference from 3.12 to 3.7 is, that there is a new itg3200 driver that 
can't be turned off by setting sampling rate to 0. Maybe it keeps cpu from idle 
by delivering constantly data.

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