MightyBear/android_device_samsung_qcom-common — pull request #1 by MightyBear007 (2013-11-16 18:24:11+00:00)
Title: qcom: properly query battery capacity

* 4.4 introduces a new daemon, healthd, that handles battery status
- resides in: /system/core/healthd
- BatteryMonitor.cpp iterates through all the *directories* under
/sys/class/power_supply looking for a file called 'type'
- if the type == Battery, it assumes this is the location for the
battery stats for the device. Only the first directory that matches
this criteria is used.
- on msm8660 and d2/jf kernels, this search results in:
/sys/class/power_supply/fuelgauge.
- To determine capacity, healthd looks at the contents of the
'capacity' file under this discovered base path. This results
in /sys/class/power_supply/fuelgauge/capacity on msm8660/d2/jf
kernels.
- Unfortunately, this is the wrong path. The capacity file at this
location returns a large negative number.
- Other paths like status, voltage_now, and present are also
incorrectly determined.
* For comparison, in 4.3 battery statistics gathering was handled by
frameworks/base/services/jni/com_android_server_BatteryService.cpp
- BatteryService does a similar search for a file called 'type' with
the contents of 'Battery'
- But the search logic is different here: it takes the *last* path that
matches the criteria.
- This results in the correct /sys/class/power_supply/battery
* This patch overrides the discovery mechanism for battery status completely.

Change-Id: I807745028bafa15f2267a37206045e96d1c40e3b