Incorrect battery level reporting in Power Off Charging Mode

[Jonathan Cave]

Vegeta had been left in the drawer for some days. On attempting to power on the device the backlight flashed briefly but the phone was unable to boot at all. This is usually a sign of completely drained battery.

Connected the device to a wall charger, device turned on and entered Power Off Charging Mode, showed the battery graphic but the reported charge level was 40%. Tried disconnecting charger with the same outcome.

Decided to flash the device using flash tool thing the was to stable r2, not sure of original version. On completing the flash and reconnecting the charger the battery graphic now read 1% which seemed more likely to be the true state of the battery.

It is possible this is the first time I have seen an incidence of this bug that was closed some time ago because of inability to reproduce: https://bugs.launchpad.net/barajas/+bug/1412310

[John McAleely (john.mcaleely)]

I have just seen this on my phone, a krillin at the tip of rc-proposed.

Taking the phone out of my bag, I noticed it was powered down, which I did not expect. Late yesterday, the phone had good charge, and I would expect the phone to idle overnight without fully discharging. Thinking I had an instance of bug #1467580, I attempted to boot to fastboot, to flash a recovery & grab logs without booting the phone.

The phone would boot to the text selection menu, but selecting either fastboot or recovery resulted in the phone booting to the 'android' charging mode. It displayed on screen an indication of 41% charge.

I am allowing the phone to charge, and will attempt to get some logs after a charging period

[John McAleely (john.mcaleely)]

On first boot, after around 20 mins of charging, the ubuntu indicator reports 33% charge level

[John McAleely (john.mcaleely)]

Battery life, as reported by ubuntu.

Note that there is no record of being so low on power the machine refused to boot into recovery or fastboot.

I'm not sure if the graphed line matches the 33% reported level

[John McAleely (john.mcaleely)]

At around the time of the battery life 'flatlining at 41%', this crash in ubuntu-push-client was logged.

[John McAleely (john.mcaleely)]

@ycheng-twn, @vicamo, I think vicamo is probably best placed to look at this and I believe there are krillin (it does repro on those) in the taipei office.

If this collides with other work, let me know.

[Yuan-Chen Cheng (ycheng-twn)]

ref: https://bugs.launchpad.net/barajas/+bug/1314951/comments/5

[John McAleely (john.mcaleely)]

@yc, I think jani's comment there might have been about this bug. The bug he commented on seems to have been about even worse differences, fixed at the time.

[Alex Kaluzhny (alex-kaluzhny)]

Observed that with version #159 rc-proposed battery level says flat at 98%, no change over 16 hours.

[Pat McGowan (pat-mcgowan)]

When in this state we should check
/sys/class/power_supply/battery
for the level there and also from
upower -i /org/freedesktop/UPower/devices/battery_battery
Also the dat files from /var/lib/upower

Not sure how ubuntu could prevent the phone from booting for a short time like that, I would assume this is under hw/fw control