termios.error: (5, 'Input/output error')

[sunbearc22]

I am encountering this error when an ESP32 device is unplugged at the usb connector.

Background: Initial serial connection was established using esptool.py, which used pyserial. I wrote a method to do certain actions when connection to the serial port is lost and not break my apprication. Below shows the error msgs:

Traceback (most recent call last):
  File "~/Esp32/test.py", line 291, in _check_connection
    self.esp.flush_input()
  File "~/.local/share/virtualenvs/Esp32-zoIgntnu/bin/esptool.py", line 392, in flush_input
    self._port.flushInput()
  File "~/.local/share/virtualenvs/Esp32-zoIgntnu/lib/python3.6/site-packages/serial/serialutil.py", line 584, in flushInput
    self.reset_input_buffer()
  File "~/.local/share/virtualenvs/Esp32-zoIgntnu/lib/python3.6/site-packages/serial/serialposix.py", line 595, in reset_input_buffer
    termios.tcflush(self.fd, termios.TCIFLUSH)
termios.error: (5, 'Input/output error')

Part of my monitoring method:

    def _check_connection( self ):
        print('\ndef _check_connection( self ):')
        if self._connected: 
            try:
                self.esp.flush_input()
            except SerialException as e:
                self._connected = False
                print( 'SerialException: ', e )
            except TypeError as e:
                self._connected = False
                self.esp._port.close()
                print( 'TypeError: ', e )
            else:
                print( 'Read! ' )
                self.after( 5000, self._check_connection ) # Check connection every 5s.

Assessment: I think both serialposix.py and esptool.py should execute lines 595 and 584, respectively, in a "try-except" statement and raise a SerialException so that users can gracefully handle error relating to disconnected serial port. I have communicated this matter to esptool.py and it's maintainer suggested I alert pyserial maintainer on this issue.