Asus Transformers have Two batteries

[phedders]

BBS looks awesome - but it gets quite confused by the Asus Transformer, which has a battery in the keyboard dock. BBS doesnt detect the second battery or the real state of charging because when docked (but not plugged in) it thinks the tablet is charging... which it is, but only from the dock. Confusing yes.

If you're interested in resolving this, please let me know how I can help debug it.

Thanks.

[asksven]

As far as I understand from the transformer construction the second battery is indeed charging the first one. This is the reason why Android detects the dock as charger (like when charging using USB).
Could you possibly add a logcat showing the dock/undock events so that I can have a closer look at how android sees this and digg into an alternate handling if there is a difference

[phedders]

On Sun, Feb 03, 2013 at 03:52:16AM -0800, asksven wrote:

As far as I understand from the transformer construction the second battery is
indeed charging the first one. This is the reason why Android detects the dock
as charger (like when charging using USB).
Could you possibly add a logcat showing the dock/undock events so that I can
have a closer look at how android sees this and digg into an alternate handling
if there is a difference

Thanks for taking an interest.

I've put a bunch of logcat up at https://gist.github.com/phedders/4754703

I will filter it a bit shortly, though it's carefully cut each side of actions like docking/undocking, and connecting power to the dock and tablet (where appropriate) so we go in and out of single and dual battery charging modes.

This app is very good at detecting the battery/charging situation - but I dont think its open source... :O(
https://play.google.com/store/apps/details?id=org.flexlabs.widgets.dualbattery&hl=en

[asksven]

Thanks for tge details. I will definitely be looking closer into this once the RC has been released.

[asksven]

Unfortunately those logs confirm what I tought: I see this happening when undocking, whether there is power connected to the dock or not:
I/OnUnplugHandler( 9377): Received Broadcast android.intent.action.ACTION_POWER_DISCONNECTED, serializing 'since unplugged'

This is consistent to what the API says: http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_DISCONNECTED

meaning there is no difference whether a battery is connected and charging or if there is a powerplug involved. Compare it to connecting your tablet to your laptop using USB: in both cases the same broadcast is fired and there is no way to get more info about what was connected.

Monitoring the charging state is different as there is a way to know the difference betwen A/C and battery (http://developer.android.com/training/monitoring-device-state/battery-monitoring.html). Unfortunately this doesn't help: during the charging, independently from being on A/C or connected to the dock battery, Android will behave the same.

I am afraid that I will not be able to fix this inconsistency

[asksven]

will not fix

[phedders]

Thanks for the consideration :)