Hi Daniel,

Thanks for your response.

On 1/28/20, Daniel Wagner [off-list ref] wrote:

Hi JH,

On Mon, Jan 27, 2020 at 01:26:41PM +1100, JH wrote:

quoted

It seems to me there are subtle differences between connman / ofono
and OpenWrt netifd, could the connman / ofono require more rigid
stable USB voltage than OpenWrt netifd? Or could the OpenWrt netifd be
more superior than connman / ofono in terms of 4G LTE connections?

Appreciate your insight comments and advice.

What about measuring the power drawn by the device? And while at it
also careful check the datasheets of the components if the tolerances
of the hardware components are meet.

I did current measuring, running ConnMan and oFono, the power
consumption was about 150mA - 260mA, running OpenWrt netifd, the power
consumption was about 150mA - 200mA. I have to say, the result might
not be accurate (1) if I change the voltage slightly, the power
consumption would be different; (2) The maximum current consumption
changes from time to time; (3) The DC power has only one output and
one current meter, I cannot connect both devices running in parallel.
I'll find a DC power supply with two power output and 2 current /
voltage meters, and to buy another debug cable to connect both devices
in parallel.

I cannot comment on netifd since I don't know anything about it. But
it could be that ConnMan and oFono together do more CPU work hence the
device drains more power. I can tell you from experience if the CPU
doesn't get enough power you see really random crashes and weird
behaviors. Check the reports on Raspberry Pi and power supplies.

Good to know that experience, it does help a lot.

Thank you Daniel,

Kind regards,

- jh