[Gta04-owner] Crowdfunding an Ubuntu smartphone

Radek Polak psonek2 at seznam.cz
Mon Aug 26 13:17:09 CEST 2013


On Saturday, August 24, 2013 03:20:10 PM joerg Reisenweber wrote:

> On Sat 24 August 2013 14:22:55 Radek Polak wrote:
> > 1/ poor power management
> 
> [...]
> 
> > something. But i always worked in userspace. I barely understand kernel
> > and i have no EE skills and equipment to contribute. I can contribute
> > only as a tester. I thought that i will deliver working userspace and
> > IMO QtMoko is very good at it. But without working kernel and HW there
> > is not much point to improve it.
> 
> many thanks for this contribution, it's already a better help than much of
> the discussion about what's wrong with our community and the GTA04 project
> at large.
> 
> However one remark about it: it's not that simple to blame kernel for poor
> power management. What we learned from last maybe 6 years of different OM
> distros and from maemo and mer and nitdroid etc is: poor power management
> is way too often caused by userland, like sensorfw and WLAN connection
> manager and X11/windowmanager and audio (alsa/PA) and whatnot else.

Yup, after playing with alsa settings i could save a few mAmps on GTA04 too.

> Often it's even rogue apps that do silly stuff like updating their system
> status icon 25 times per second or constantly chatting with internet or
> even just polling files when you should use inotify instead.
> Kernel power saving measures are relatively simple to test and fix, and
> usually it's not kernel to blame for abysmal standby time and/or operation
> time.
> 
> To give you a simple example: on N900 maemo you have "scanning period" in
> settings-internet, which makes device scan for WLAN APs only every 5, 10,
> ... even 30 min. This is needed since the WLAN chip cuts thru the battery
> in less than 3 hours when you constantly scan for APs. Clearly a userland
> issue where kernel can't do much. Now you can start to blame kernel WLAN
> driver for not doing proper powersaving but that won't help establish a
> decently working usable OS on N900.

I think in case of QtMoko on GTA04 we can blame kernel/HW a little bit more, 
since we are using suspend to RAM whereas N900 is always on (which really cool 
btw). So while GTA04 is in standby there should be idealy just PMU+RAM+modem 
turned on, everything else should be off. But something is wrong and noone has 
yet figured what it is. At best there is ~16mA with omap enable_off_mode - but 
then we hit "imprecise external abort" bug so currently we have ~22mA at best. 
If you compare this with GTA02 or N900 it's really bad. GTA02 is 12mA and i'd 
say N900 is even better. Together with reenumerating modem it makes GTA04 
barely usable even for a few hardcore supporters but unusable for normal 
users.

Regards

Radek
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