[Community] GTA04A5 / Letux 2804

[Rico Rommel]

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 
extend.

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 
C-States.

It was already mentioned here:
http://lists.goldelico.com/pipermail/gta04-owner/2013-November/005152.html

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.

Rico
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