02-23-2021, 03:38 PM
(07-22-2020, 01:34 PM)jrobin28260 Wrote: Hi all,
I did a LTE max bandwidth test, on a good place for being alone on the carrier's antenna (LTE 2600, 20 MHz, 1 out of 3 panels directed right into a big forest.
Reached 140 Mbps few seconds and was moving from 125 Mbps to 135 Mbps at low CPU usage (around 20%) half of the time : seems to work really fine, as the maximum possible value of LTE cat 4 is 150 Mbps
However, when using modem, the phone has lots of "seizures moments", during few seconds it lags a lot, freezes a lot, and then come back to normal during few seconds before becoming mad again. It's 50/50 of the time.
When doing the same tests on WiFi, the issue does not exists : it only exists when using modem.
It's not due to temperature as CPU and GPU temperature shows approximately 50°C or even below when the problem already occurs. When the problem occurs, the download bandwidth falls back to almost 0 to few Mbps, and goes up again after the CPU behavior goes back to normal.
Viewing CPU usage on "top" command, within and outside "seizure" moments, the order of which program was using the CPU (aria2, bwm-ng, lxterminal etc) and proportions were the same, but during seizure moments, every usage value is just strongly multiplied.
Is this a known issue? Is there some software workaround about it?
It looks a little bit like CPU power issues, as for Intel/AMD CPU and VRM, in case of insufficient power supply or too hot VRM, CPU is repeatedly doing short freezes waiting things to be normal again, giving similar symptoms.
Also, when enabling modem with low backlight intensity, the backlight intensity is lowering.
But in the others hand, when doing uplink bandwidth test, the problem does not occur (while according to lm-sensors, uplink is consuming more current, 1.2 Amps instead of 1.0 Amps).
I'm using Mobian kernel from here https://gitlab.com/mobian1/devices/pinephone-linux, downloaded and built on 2020/07/19, on Pinephone UBports community edition (1.2 if I'm right - at least I'm using 1.2 DTB).
How to go further in the understanding of this issue?
Setting the CPU governor to `powersave` fixed it for me. I dont know why.
