Inverted GPIO power pin is turned on briefly every time Moonraker loads

Arakon commented 6 months ago

What happened

I have a Lerdge Power Monitor relay which requires an active low signal to turn on. It's connected to GPIO23 on the raspberry pi. The config looks like this:

[power printer]
type: gpio
pin: !gpiochip0/gpio23
off_when_shutdown: True
restart_klipper_when_powered: true
initial_state: off

Whenever Moonraker starts up, after powering on the Pi or restarting the Moonraker service, it will briefly turn on the relay and then back off. However, if the pin is NOT inverted, the relay turns on as soon as Moonraker starts up, and stays on (which is expected), and does not briefly turn it off. Note that the relay doesn't toggle during Pi startup or when Moonraker is not launched, so this is definitely triggered by Moonraker. I also tried with GPIO4 instead, with the exact same behavior. On another printer, with an active high relay, and non-inverted GPIO pin, the relay is only triggered when commanded.

Expected behavior: Moonraker keeps the default GPIO state until actively instructed otherwise. moonraker.log

Client

Fluidd

Browser

Firefox

How to reproduce

Attach an active low triggered relay to a GPIO
Set up Moonraker to switch it as a power toggle with an inverted GPIO
Start or Restart Moonraker and notice that the GPIO is triggered briefly on launch

Additional information

No response

Arksine commented 6 months ago

Thanks. This should be resolved in commit ea6df41f05a11622f4377bf26a09a08edb773378.

Arakon commented 5 months ago

Fixed. Thanks for the quick response!

Arakon commented 5 months ago

One small addition: When shutting down the host, the pin does not turn off. Is this something that can be done on the moonraker side?

Arksine commented 5 months ago

Generally Moonraker does not change power device state when it shuts down for any of its implementations. It does release the gpio line and its possible that libgpiod reset the pin's state to whereas python-periphery does not. I'm willing to look into it, but I'm also hesitant to make a change here. Consider that if your pin is inverted then resetting the state may power on a relay.

Arksine commented 5 months ago

I did look into this and this behavior hasn't changed with python-periphery as libgpiod also leaves the line state unchanged after release. I don't think it would be appropriate for Moonraker to make assumptions about what the line state should be when the service is stopped, so I'm inclined to leave the behavior as is.

Arksine / moonraker