SerialException: [Errno 16] could not open port /dev/ttyACM0: [Errno 16] Device or resource busy: '/dev/ttyACM0'

[sentry-io]

Sentry Issue: PROS-CLI-3-30

OSError: [Errno 16] Device or resource busy: '/dev/ttyACM0'
  File "serial/serialposix.py", line 265, in open
    self.fd = os.open(self.portstr, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK)

SerialException: [Errno 16] could not open port /dev/ttyACM0: [Errno 16] Device or resource busy: '/dev/ttyACM0'
  File "pros/cli/upload.py", line 94, in upload
    ser = DirectPort(port)
  File "pros/serial/ports/direct_port.py", line 20, in __init__
    self.serial: serial.Serial = create_serial_port(port_name=port_name, timeout=kwargs.pop('timeout', 1.0))
  File "pros/serial/ports/direct_port.py", line 11, in create_serial_port
    parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE)
  File "serial/serialutil.py", line 240, in __init__
    self.open()
  File "serial/serialposix.py", line 268, in open
    raise SerialException(msg.errno, "could not open port {}: {}".format(self._port, msg))

SerialException: [Errno 16] could not open port /dev/ttyACM0: [Errno 16] Device or resource busy: '/dev/ttyACM0'

This should be just catching the exception properly and suppressing it. We should add some hints to why we can't open the port:

• someone already has it
• user is not part of dialout group

[HotelCalifornia]

user is not part of dialout group

This typically results in Errno 13 (lack of permission) rather than this device or resource busy one

[baylessj]

I also experience this issue when uploading on ubuntu. The workaround I've found is to run sudo chmod a+rw /dev/ttyACM0 every time that I connect my computer to the brain, but it is a bit frustrating to have to run that every time.

I'm guessing there's got to be some sort of option to set these read/write permissions automatically upon plugin, but I haven't explored that option yet.

[edjubuh]

Yes, add yourself to the dialout group

[Octogonapus]

sudo usermod -a -G dialout salmon, for example. Then restart.

[HotelCalifornia]

I also experience this issue when uploading on ubuntu.

Strictly speaking, that's technically a separate thing.

Yes, add yourself to the dialout group

This can be done with sudo usermod -a -G dialout <your_username>. I've seen this issue crop up enough times that we should probably make a note of it somewhere on purduesigbots/pros-docs.