[BPI-R3] Powerusage/poweroff


After getting most things done i measured power consumption.

  • 2 fibre sfp plugged (one with active link,the other only admin-up)
  • lte modem inserted to mPCIe Slot (without active connection)
  • nvme in m.2 slot
  • both wifi active in AP-Mode

I get 7.6 watts in cpu-idle.

After running poweroff it is 8.2w…i expected to get at least little lower consumption. Any idea where to look?

@frank-w Is it possible the system just hangs during poweroff? Which image are you running? In my case poweroff just restarts the board, I don’t have sfp’s and reading 4.6w (idle). I’m on 3 days old snapshot

I run debian on it and it looks like poweroff is done (green led of my kernel goes off).

I know real poweroff is not supported by pmic driver,but it should poweroff at least some peripherals like wifi,pcie-controller and such, i guess not yet supported…but more consumption than on running state is strange

lte connection does not make much difference ~0.1w, do maximum cpu-usage (4x dd if=/dev/urandom) adds 1W, so my maximum power-consumption is ~8.4w

after running poweroff-command it looks like clean poweroff

[  911.935407] systemd-shutdown[1]: Powering off.
[  912.575826] reboot: Power down

in this test i have 7.7w after this…

after basic bootup (lte-modem recognized, wifi not enabled because of module not loaded is ~5.5w)

@SergeS how is your power consumption after calling poweroff command? I remember reboot on r64 after poweroff,but there was a delay of >10s

asked this question to mtk and got this answer:

The MT7986 SoC includes CONSYS (wifi), ETHSYS (Ethernet), MCUSYS (CPUs), peripherals… and many other subsystems. Since we don’t have a PMIC design in the MT7986 SoC, as far as I know, I think those subsystems are always powered on when the BPIR3 board is powered on. We usually use a power switch on the RFB to turn it off manually.

When the “poweroff” command is sent to Linux system, Linux system calls MT7986’s ATF through the SMC calls to shut down every CPU inside the MCUSYS, But I think the MCUSYS itself still draws power directly from the BPIR3 board. And in the CONSYS case, Linux removes Wifi driver during power off, and our WiFi driver will stop WiFi mcu inside the CONSYS by holding the reset signal on it, But as the case of the MCUSYS, the CONSYS itself still draws power directly from the BPIR3 board.