PRS-T1 Battery drains over night - possible cause!

[uboot]

Hi folks,

I had my T1 battery drain over night occassionally and tried many things to solve this like using advanced task manager to auto-kill apps when screen off, permit apps from using wake locks via permission denied app, etc. but this didn't solve the issue.

I'm using BetterBatteryStats app to track down this issue and found the reader often not going to deep sleep, but have almost equal awake time and screen off time (select other in drop down menu to check this). Furthermore, there is a kernel module named switcher causing lots of wake ups (select kernel wake lock to check this).

Well, I didn't figure out what this switcher module is for, but it seems that the issue happens when:

1.) the reader is powered off
2.) connect charger -> reader switches on and charges
3.) disconnect charger when fully charged

From now on it seems more likely that the reader won't really go to sleep when screen is powered off.

If I do a reboot, everything is back at normal. Switcher module does not cause wakeups anymore.

I suspect that connecting the charger with reader powered off triggers some bug in the kernel.


Please fill the poll, that would help a lot to track this issue down further.

[rupor]

switcher is Sony service supporting private communication protocol over USB. It seats on device, listens for USB states and executes commands sent by Reader for PC (or ebook_msc.exe) via DeviceAccessor.dll. All those get, um, etc.

I doubt it is kernel bug - more than likely (if you are right) it is switcher itself since it is sufficiently different between 1.04 and Russian version of firmware (2.0...)

[uboot]

hm, ok...

but switcher is a kernel module, isn't it? cause betterbatterystats does list it under kernel wakelocks.

now, we'll need to find a way to temporarily disable switcher.... or adapt russian firmware if it is bugfixed...

[rupor]

I do not think so. From init.rc:

# switcher daemon
service switcher /system/bin/switcher
    user root

You probably would be able to kill and restart it (never tried it myself) as "normal" daemon. As for Russian firmware - again, I am not sure how it is written and where it get a key, but Russian firmware is using different versions of system libraries and different encryption key. So I do not think you could simply replace it...

May be kernel has some other switcher? Not sure - but in this case I am sorry for confusion.

[Lbooker]

Somnolecturum.