Hi guys,

I am running bananapi and cubietruck boards and these board are axp209 power management unit equipped (tech details about this unit: http://linux-sunxi.org/AXP209).One advantage of this unit is showing informations about actual voltage and current of power source because as you know we are surrounded with many bad cheap power sources and microusb cables and monitoring of these informations can help explain corrupted data on microsd cards or random reboots. It show informations about battery status and usb voltage and current as well if battery is connected. 

I am using axp209 enabled RPi-Monitor from link https://github.com/XavierBerger/RPi-Monitorand I am sure when I was writing post link below it was working and I did not see any unusual zero values in RPi-Monitor.

http://forum.armbian.com/index.php/topic/44-banana-pi-with-dvb-support/

 

I tried find out what is happening and I found problem in /sys tree. When I do command bellow I see zero values in last 2 bottom rows.

 

cat /sys/devices/platform/sunxi-i2c.0/i2c-0/0-0034/axp20-supplyer.28/power_supply/*/* | head -n 11

 

POWER_SUPPLY_MODEL_NAME=ac
POWER_SUPPLY_PRESENT=1
POWER_SUPPLY_ONLINE=1
POWER_SUPPLY_VOLTAGE_NOW=0
POWER_SUPPLY_CURRENT_NOW=0

 

Output of this command is on both bananapi and cubietruck exactly same.

 

I am running these boards on 3.4.109 kernel and I remember it was ok in earlier versions kernel.

 

Where can I get older kernels before this problem will be sorted out? (I am sorry but I do not know how to repair this issue)

 

Thank you for your answers.

 

Update:

I tested these kernels below today and problem is same with all. Kernel stopped feeding sys tree:

/sys/devices/platform/sunxi-i2c.0/i2c-0/0-0034/axp20-supplyer.28/power_supply/ac/subsystem

after few minutes after reboot.

 

3.4.106-cubietruck-default
3.4.107-cubietruck-default
3.4.108-cubietruck-default

 

I made all test with battery connected.

Hi guys, update. I checked both boards and Rpi-Monitor is able to collect the informations from pmu for about 2 days without any drops. I do not know what exactly solved this problem. I lowered voltage down a bit on a step-down converter so now PWR voltage is between 4.8-4.9V instead 5.0-5.1V and upgraded some system packages which Igor released a few day ago. If I will have time I will do some tests to repeat same conditions to find what caused this.

 

SOLVED !