read from slave as regular serial device

[christianrauch]

I created two simple test programs in Python to send and receive data:

Write to master send.py:

#!/usr/bin/env python3
import serial
import time


if __name__ == '__main__':
    # causes: termios.error: (25, 'Inappropriate ioctl for device')
    # serial_port = serial.Serial(
    #    port='/dev/vtmx',
    #    baudrate=100000,
    #    parity=serial.PARITY_EVEN,
    #    stopbits=serial.STOPBITS_TWO,
    #    bytesize=serial.EIGHTBITS)

    serial_port = open('/dev/vtmx', 'w')

    while True:
        try:
            for i in range(10):
                msg = str(i)
                serial_port.write(msg)
                serial_port.flush()
                print(f"sent {msg}")
                time.sleep(0.5)
        except KeyboardInterrupt:
            break

    serial_port.close()

Read from slave recv.py:

#!/usr/bin/env python3
import serial

if __name__ == '__main__':
    serial_port = serial.Serial(
       port='/dev/ttyV0',
       baudrate=100000,
       parity=serial.PARITY_EVEN,
       stopbits=serial.STOPBITS_TWO,
       bytesize=serial.EIGHTBITS)

    print(f"serial port open: {serial_port.is_open}")

    while True:
        byte = serial_port.read()
        print(chr(byte))

    serial_port.close()

However, instantiating the serial port gets stuck somewhere at termios.tcsetattr.

How do I configure the master device such that I can read from the slave like a regular serial device?

[anszom]

This must be a bug. I've checked this now on two random machines - it works on one (kernel 5.15) but fails on the other (kernel 5.4).