928884 - [Flatfish] The charger behaviour when user plug in USB cable in tablets

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Gaia::System, defect)

Description

[viral [:viralwang]]

In tablets, when we plug in USB cable, it will shows charging in beginning but becomes "not charging" later since the charging power is less than consumption power.

The most bother part is that when device enter suspend mode (screen off), the power consumption will drop and cost less power than the USB charging. It becomes charging again and the device will resume (screen on). User will see the screen is continuously on/off if we plug in USB cable.

Comment 1

[viral [:viralwang]]

Hi Harly,

As our discussion today, could you please provide some ideas about the behaviour we expect when USB plug-in?
Thank you!

Comment 2

[Harly Hsu[:harly]]

Hi Viral,
One quick question, do our tablet have a LED light indicating that the tablet is charging?

(In reply to viral [:viralwang] from comment #1)
> Hi Harly,
> 
> As our discussion today, could you please provide some ideas about the
> behaviour we expect when USB plug-in?
> Thank you!

Comment 3

[Harly Hsu[:harly]]

Hi Viral,
According to the discussion earlier,
we think that it is better to light up the screen only once if the tablet is in suspend mode and use USB charging.
The battery icon will remain what it is right now.
Thank you! 


(In reply to hhsu from comment #2)
> Hi Viral,
> One quick question, do our tablet have a LED light indicating that the
> tablet is charging?
> 
> (In reply to viral [:viralwang] from comment #1)
> > Hi Harly,
> > 
> > As our discussion today, could you please provide some ideas about the
> > behaviour we expect when USB plug-in?
> > Thank you!

Comment 4

[RaymondSu]

For current Flatfish device, there is no LED light to indicate the charging/discharging status.

Our idea for the behaviors when USB port of FxOS device is plugged are as below.
1. Device is ON:
1.1 If plug with adapter to the wall:  --> Screen light on to show device is plugged well to the wall.  --> show charging status (from status bar? battery animation or LED someday?) --> Go sleeping and keep charging.  No more light up if no other interrupt event trigger

1.2 If plug with PC USB port: --> Screen light on to show device is plugged well to the PC
1.2.1 Keep awake and power consuming if user is working between PC and FxOS device (for example, USB Mass storage mode, gallery pickup...etc.)
1.2.2 Go sleep (screen light off) and keep black screen after being idle some minutes.  No more wake up to light on screen even system start charging.

2. Device is OFF:
2.1 Judge the power on voltage threshold to safety power on into FxOS Home.
If extremely low voltage, show low voltage battery icon/animation and keep FxOS charging until 2.2 condition.  If user press the power key again, showing the low voltage battery icon/animation and prevent system being power on further to FxOS launcher.
2.2 If battery voltage is in certain safety level to power into FxOS, Device is ON and go with scenario 1. flow.

The main idea is to judge by port plug/unplug to light on the screen instead of charging/discharging.

Comment 5

[viral [:viralwang]]

Hi Harly,

Shall we have any feedback for the comment 4 in your point of view?

Comment 6

[Harly Hsu[:harly]]

Hi Viral,
From what I have seen in comment 4 and what we proposed previously, the difference is that Sulapy will want to keep the tablet awake while in USB mass storage mode, gallery pickup...etc. However, since USB doesn't have enough power to charge the tablet while the screen is on, and also this will conflict with screen timeout in Settings. I suggest that we stick with our previous plan. Thanks

Comment 7

[RaymondSu]

As my comment 1.2.2, if after idle for a while, (based on Settings about screen timeout), it still can go to sleep.

Comment 8

[RaymondSu]

oops, I think I made wrong words the c#7.  My c#4 1.2.2 means "screen light off".  Some tasks using USB connection such as adb should keep alive.

Comment 10

[YF (Yang)]

http://mxr.mozilla.org/gaia/source/apps/system/js/battery_overlay.js

Comment 11

[YF (Yang)]

I trying to create a "b2g.chargingchange_screenOn.disabled" in gaia/build/config/tablet to disable this point for tablet, but I could not implement a read in battery_overlay.js, whether for perfs.js or settings.json...

Any helping is welcome.

Comment 12

[BMO Automation]

Firefox OS is not being worked on