Re: Hibernation / Supsend to Disk
 

My empiral evidence (aka my anecdote) is that the four reboots is enough to bring the N810 battery to its knees.

Without rebooting, it lasts around two days of medium use, and a week of light use.

Re: Hibernation / Supsend to Disk
 

Interesting idea.

I have a feeling that switching to off-line mode would conserve more power overnight than hibernating. Although the internal storage "disk" has no moving parts, I'm guessing that writing, then reading back on restore, 256 MB is still relatively power hungry? Plus the additional overheads on both sides.

I really doubt Suspend would be worth it either, as power conservation has always been a top priority for Maemo. I guess switching to off-line mode overnight would gain that tiny bit extra and is effectively Standby mode, as there would be no need for the device to perform any actions so virtually no power consumption from internal components.

I do like the idea of Hibernation for battery swaps though. Not an issue for my current usage of N810 + E90, but could see this occuring with the N900 as my single device, with all that gorgeous computing power at my disposal 24/7 - I feel almost obliged to use it to it's max! :D

Re: Hibernation / Supsend to Disk
 

Hildon has already a framework for battery swapping "hibernation". I've never seen it working, though (save when you don't have swap enabled and ZZZ appears on a task switcher icon).

Re: Hibernation / Supsend to Disk
 

Yes, because your "here's some math I did in my head with numbers I've estimated and numbers I've guessed" is so convincing.

I'd rather not waste their time to have them help me win a silly forum fight.

Re: Hibernation / Supsend to Disk
 

My personal wacko EE theory is that booting is not as strenuous as it seems at first glance, but does for some reason mess up the charge indicator/battery chemistry/power management in general, which in turn can/will influence possible runtime. I'm pretty certain it's not 'straight current draw' after losing 30% battery power on a N810 reboot (that would result in a serious meltdown if true :) ), and after gaining 7% on another (unrelated) reboot.

Re: Hibernation / Supsend to Disk
 

does hibernating really take as much power as a normal shutdown/reboot?
is hibernation more than saving used pages to flash (may be compressed), kernel init and reloading the pages from flash?

Granted, whether you can actually save power by hibernation compared to off-line mode depends on how long you don't need to use the device, but continuous discharging of the battery could also reduce battery life, correct?

However, for me the main purpose of hibernation is not necessarily to save power, but to be able to restore all application states after a period of power off.

Suppose your battery is low after a long day of intense use and you can only recharge it when you come back to your desk.
Now you have two options:

1) turn the device off and lose the session state (running applications) or

2) hibernate, and wake up as soon as it is connected to power again (or you have swapped the battery).

Don't you think that 2) would be a useful feature?

Re: Hibernation / Supsend to Disk
 

I believe there are two issues:
- What you're explaining is correct. Even the builtin battery meter tends to keep on saying "the battery just got better" ;) up to an hour after rebooting.
- Tracker. Or metalayer or whatever it's called on Diablo. Indexing 4 GiB takes a load of time -- plenty of time to suck power without overheating anything.

I've also found a few weird things. First reboot usually shows 100% battery even if before rebooting it was at 90%. Second reboot shows half the battery. Every other reboot shows "battery low" warning. This was with around half an hour between reboots (was trying to create a hildon-desktop patch and messed something up:) ).

Re: Hibernation / Supsend to Disk
 

Makes sense.

Agreed.

Re: Hibernation / Supsend to Disk
 

Hibernate would be neat sure, but i know that resurecting is causing lot of issue specially with some hardware ...

But if it saves the batteries it would reduce flash life...

Talking about that, is powertop available for ARM ?

Re: Hibernation / Supsend to Disk
 

This would be a very interesting feature, not seldom used a lot, but there are several circumstances I wish I could just remove the battery/change SIM without going through a full reboot. Could be a nice feature to be implemented by the community. Any coders around for it?