maemo.org - Talk - View Single Post - Debugging a "battery dead in the morning" issue

	javispedro	2009-05-23 , 11:39
	Posts: 2,355 \| Thanked: 5,249 times \| Joined on Jan 2009 @ Barcelona	#1

I usually leave the N810 in flight mode and muted at night. Twice in a month (or so) I awake to find the battery completely dead. I've read some threads here -- most solutions say something along the lines of "do not leave any app open" (I don't), "check if your wifi ap support psm" (flight mode), "reflash" (already done it, but I cannot spend a month with the tablet in a useless state to fully test it).

Since it may also be one of my little helper applications I've coded for it, I tough I may give it a try and try to debug the cause.

First step: a program which regularly dumps raw battery voltage (kcbatt) and 15 minute average load:

On a "good" night (snippet):

Code:

Timestamp  Voltage "Average Load" "Time"
1242612338	553	0.00	Mon May 18 02:05:38 2009
1242613239	553	0.00	Mon May 18 02:20:39 2009
1242614139	552	0.00	Mon May 18 02:35:39 2009
1242615039	552	0.00	Mon May 18 02:50:39 2009
1242615939	552	0.00	Mon May 18 03:05:39 2009
1242616839	552	0.00	Mon May 18 03:20:39 2009
1242617739	552	0.00	Mon May 18 03:35:39 2009
1242618639	552	0.00	Mon May 18 03:50:39 2009
1242619539	552	0.00	Mon May 18 04:05:39 2009
1242620439	552	0.00	Mon May 18 04:20:39 2009
1242621339	551	0.00	Mon May 18 04:35:39 2009

On a "bad" night:

Code:

1243047636	504	0.02	Sat May 23 03:00:36 2009
1243048537	506	0.17	Sat May 23 03:15:37 2009
1243049437	497	0.12	Sat May 23 03:30:37 2009
1243050337	488	0.10	Sat May 23 03:45:37 2009
...
1243062938	420	0.08	Sat May 23 07:15:38 2009
1243063838	415	0.10	Sat May 23 07:30:38 2009
1243064738	409	0.09	Sat May 23 07:45:38 2009
1243065639	403	0.10	Sat May 23 08:00:39 2009
1243066539	394	0.10	Sat May 23 08:15:39 2009
1243067439	382	0.09	Sat May 23 08:30:39 2009
1243068339	370	0.13	Sat May 23 08:45:39 2009
1243069239	334	0.09	Sat May 23 09:00:39 2009
(log stops here -- battery dead)

As you can see, the average load on a "bad night" is never 0. At least, I can confirm this is not a "kernel crashes and tablet spends rebooting the whole night", which I suspected (since I'm using custom kernel).

So right now I need an application which can tell me who or what is causing the extra load, and I was wondering if someone has done something similar already. Or some idea of what to log to identify the culprit application (periodic top? ordered by current cpu usage, used cpu time?).

As I said, it happens hardly often so trial-and-error is nearly out of the question.

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