GMC exceeds timeout but default pyserial terminator empty-byte-str doesn't raise timeout error.

[Wikilicious]

The symptom is pygmc.connect() takes forever and ultimately fails to connect (failing as-in not finding a GMC to connect to, no exception raised)
This is on Ubuntu via VMware with correct udev rules #105 (fix it already Ubuntu!)

Log:

>gc = pygmc.connect()
...
DEBUG:pygmc.connection:Matched devices: [('/dev/ttyUSB1', 'USB VID:PID=1A86:7523 LOCATION=1-2.1')]
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB1 baudrate=115200
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b'GMC-500'
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b'+Re 2.22'
DEBUG:pygmc.connection:combined-response=b'GMC-500+Re 2.22'
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x713193a531c0, open=True>(port='/dev/ttyUSB1', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB1 baudrate=57600
...

Can see empty <GETSERIAL>> yet no error (not shown in logs... it did take 3 seconds to reply)

Was able to reproduce in pure pyserial... (in same session. i.e. no usb reconnect, jupyter notebook restart, etc...)

con = serial.Serial(port='/dev/ttyUSB1', baudrate=115200, timeout=3)
w = con.write(b"<GETSERIAL>>")
print(f'{w=}')
# w=12
_serial_number = con.read_until(terminator=b"", size=7)
print(f'{_serial_number=}')
# _serial_number=b''

A con.read_all() was attempted some time after... empty result. (after the above example with no buffer reset)

Within same session, I tried con.read_until(terminator=b"DeliciousPyGMC", size=7) and then it finally returned a response.

There may be two possible issues here...

1. The terminator=b"" param has some awkward handling when used with pyserial timeout & size (no exception raised)
2. GQElectronics GMC has some bug that returns empty response. (GMC map is enabled and running & device hasn't been powered off in a few months)

PyGMC=0.14.1

[Wikilicious]

Rebooted PC (and VMware along with it) and fresh start had same issue!

DEBUG:pygmc.connection:Matched devices: [('/dev/ttyUSB0', 'USB VID:PID=1A86:7523 LOCATION=1-2.1')]
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=115200
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf1aa920, open=True>(port='/dev/ttyUSB0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=57600
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8a46ef0, open=True>(port='/dev/ttyUSB0', baudrate=57600, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=38400
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8a46e60, open=True>(port='/dev/ttyUSB0', baudrate=38400, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=28800
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8a46ec0, open=True>(port='/dev/ttyUSB0', baudrate=28800, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=19200
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf1aa920, open=True>(port='/dev/ttyUSB0', baudrate=19200, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=14400
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf181c60, open=True>(port='/dev/ttyUSB0', baudrate=14400, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=9600
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8bfbb50, open=True>(port='/dev/ttyUSB0', baudrate=9600, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=4800
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf134c70, open=True>(port='/dev/ttyUSB0', baudrate=4800, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=2400
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8a46f20, open=True>(port='/dev/ttyUSB0', baudrate=2400, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=1200
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb8bfa800, open=True>(port='/dev/ttyUSB0', baudrate=1200, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)

---------------------------------------------------------------------------
ConnectionError                           Traceback (most recent call last)
Cell In[3], line 1
----> 1 gc = pygmc.connect()

File ~/code/pygmc/pygmc/__init__.py:84, in connect(port, baudrate, timeout)
     82     # line below logs & prints info for user to resolve USB connection issue
     83     brltty_udev_rule_check.get_offending_brltty_rules()
---> 84     raise ConnectionError("No GMC devices found.")
     86 device_details = discovered_devices[0]
     88 logger.debug(f"Selecting: {device_details}")

ConnectionError: No GMC devices found.

The raw pyserial connection method had same issue.
This device, GMC-500+ powered on for a few months continuously, with WiFi sending data to https://www.gmcmap.com
Data is up-to-date on gmcmap.

[Wikilicious]

Tried again and got a new unexpected error...

DEBUG:pygmc.connection:Matched devices: [('/dev/ttyUSB0', 'USB VID:PID=1A86:7523 LOCATION=1-2.1'), ('/dev/ttyUSB1', 'USB VID:PID=1A86:7523 LOCATION=1-2.3')]
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=115200
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb81d1e10, open=True>(port='/dev/ttyUSB0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=57600
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf1830a0, open=True>(port='/dev/ttyUSB0', baudrate=57600, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=38400
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798ccf1820b0, open=True>(port='/dev/ttyUSB0', baudrate=38400, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=28800
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:get_exact(cmd=b'<GETSERIAL>>', size=7, expected=b'')
DEBUG:pygmc.connection:write='b'<GETSERIAL>>''
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:get(cmd=b'<GETVER>>', wait_sleep=0.01)
DEBUG:pygmc.connection:write='b'<GETVER>>''
DEBUG:pygmc.connection:read_at_least(size=7, wait_sleep=0.01)
DEBUG:pygmc.connection:read_until(size=7, expected=b'')
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:read_all
DEBUG:pygmc.connection:response=b''
DEBUG:pygmc.connection:combined-response=b''
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
DEBUG:pygmc.connection:reset_input_buffer
DEBUG:pygmc.connection:reset_output_buffer
INFO:pygmc.connection:Close connection: Serial<id=0x798cb89746d0, open=True>(port='/dev/ttyUSB0', baudrate=28800, bytesize=8, parity='N', stopbits=1, timeout=5, xonxoff=False, rtscts=False, dsrdtr=False)
DEBUG:pygmc.discovery:Checking port=/dev/ttyUSB0 baudrate=19200

---------------------------------------------------------------------------
BrokenPipeError                           Traceback (most recent call last)
Cell In[7], line 1
----> 1 gc = pygmc.connect()

File ~/code/pygmc/pygmc/__init__.py:76, in connect(port, baudrate, timeout)
     46 """
     47 Connect to device.
     48 
   (...)
     70     Unable to connect to device.
     71 """
     72 # Difficult choice... Discovery is temporary... and is nearly always instant or
     73 # requires user action to dis/re-connect USB. (i.e. nothing pygmc can do)
     74 # So why make a long timeout? Fail fast but override Discovery timeout or fail slow
     75 # and use user provided timeout?
---> 76 discover = Discovery(port=port, baudrate=baudrate, timeout=timeout)
     77 discovered_devices = discover.get_all_devices()
     79 if len(discovered_devices) == 0:
     80     # Give user direction in case of brltty udev rule blocking GMC USB device

File ~/code/pygmc/pygmc/connection/discovery.py:39, in Discovery.__init__(self, port, baudrate, timeout)
     37 self._timeout = timeout
     38 self._discovered_devices = []
---> 39 self._discover_devices_flow(port=port, baudrate=baudrate)

File ~/code/pygmc/pygmc/connection/discovery.py:55, in Discovery._discover_devices_flow(self, port, baudrate)
     52     self._discover_with_known_baudrate(baudrate=baudrate)
     53 else:
     54     # lemme just do everything for you... likely most common case
---> 55     self._discover_all()

File ~/code/pygmc/pygmc/connection/discovery.py:172, in Discovery._discover_all(self)
    169 ports = self._get_gmc_usb_ports()
    170 for port in ports:
    171     # D.R.Y. (don't repeat yourself)
--> 172     self._discover_with_known_port(port=port)

File ~/code/pygmc/pygmc/connection/discovery.py:164, in Discovery._discover_with_known_port(self, port)
    162 def _discover_with_known_port(self, port) -> None:
    163     for baudrate in BAUDRATES:
--> 164         is_valid = self._validate_device(port=port, baudrate=baudrate)
    165         if is_valid:
    166             break

File ~/code/pygmc/pygmc/connection/discovery.py:130, in Discovery._validate_device(self, port, baudrate)
    128 logger.debug(f"Checking port={port} baudrate={baudrate}")
    129 try:
--> 130     conn = Connection(port=port, baudrate=baudrate, timeout=self._timeout)
    131 except SerialException as e:
    132     # Should a convenience method log as warning/error?
    133     # If only GQ Electronics would put the version/serial in USB description...
    134     logger.warning(f"Skipping error connecting: {e}", exc_info=True)

File ~/code/pygmc/pygmc/connection/connection.py:66, in Connection.__init__(self, port, baudrate, timeout, serial_connection)
     64     logger.warning(f"Known compatible baudrates={BAUDRATES}")
     65 try:
---> 66     self._con = serial.Serial(port=port, baudrate=baudrate, timeout=timeout)
     67 except TimeoutError:
     68     # See issue #112
     69     # Windows-running-VMware-running-Ubuntu - sleep-wake - USB issue
     70     # And # 118
     71     # Bad USB cable/connection causing unreliable communication.
     72     logger.exception(
     73         "TimeoutError - consider reconnecting USB or replacing USB cable."
     74     )

File ~/notebook/.venv/lib/python3.10/site-packages/serial/serialutil.py:240, in SerialBase.__init__(self, port, baudrate, bytesize, parity, stopbits, timeout, xonxoff, rtscts, write_timeout, dsrdtr, inter_byte_timeout, exclusive, **kwargs)
    237     raise ValueError('unexpected keyword arguments: {!r}'.format(kwargs))
    239 if port is not None:
--> 240     self.open()

File ~/notebook/.venv/lib/python3.10/site-packages/serial/serialposix.py:286, in Serial.open(self)
    284 try:
    285     if not self._dsrdtr:
--> 286         self._update_dtr_state()
    287     if not self._rtscts:
    288         self._update_rts_state()

File ~/notebook/.venv/lib/python3.10/site-packages/serial/serialposix.py:634, in Serial._update_dtr_state(self)
    632 """Set terminal status line: Data Terminal Ready"""
    633 if self._dtr_state:
--> 634     fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str)
    635 else:
    636     fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str)

BrokenPipeError: [Errno 32] Broken pipe

I added a GMC-300S this time (both USB available)... thinking PyGMC will roll off to connect to this... but it had an error while communicating with GMC-500+
Disconnected the GMC-500+ and only had the GMC-300S (on different USB cable a USB-C) It connected... but suspiciously took 11 seconds (it's usually instant!)

My PC got a BSOD on Jan 16, 2025 at 4:38PM and has been acting up... so maybe just a local-to-me issue.

[ffries]

I can confirm this issue. I can see empty <GETVER>> and when I request a second time it is printed.