Offline (Error: IOError: '[Errno 25] Inappropriate ioctl for device' @ comm.py:_readline:2739)

Hi there,
What is the problem?

I cannot connect to my Prusa i3 MK3S with MMU2S from the Raspberry zero W connected to the Einsy board. I get the error message:
Offline (Error: IOError: '[Errno 25] Inappropriate ioctl for device' @ comm.py:_readline:2739).

What did you already try to solve it?
I have contact the Prusa helpline and I controlled the soldering on the pi, the settings on the i3, disconnect the MMU2S, adding the serial port: /dev/ttyAMA0, downgrade to firmware, change the baud rate manually to 115200 from AUTO, factory reset and reflash the firmware back to 3.7.0,

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)

*OctoPrint 1.3.11 running on OctoPi 0.16.0,
Prosa i3 MK3S MMU2S firmware 3.7.1-2266

serial log:

*2019-05-16 18:39:24,759 - Enabling serial logging*
*2019-05-16 18:40:21,394 - Connecting to: /dev/ttyAMA0*
*2019-05-16 18:40:21,407 - Changing monitoring state from "Offline" to "Opening serial port"*
*2019-05-16 18:40:21,450 - Connected to: Serial<id=0xafd89f70, open=True>(port='/dev/ttyAMA0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor*
*2019-05-16 18:40:21,461 - Changing monitoring state from "Opening serial port" to "Connecting"*
*2019-05-16 18:40:21,533 - Unexpected error while reading serial port, please consult octoprint.log for details: IOError: '[Errno 25] Inappropriate ioctl for device' @ comm.py:_readline:2739*
*2019-05-16 18:40:21,546 - Send: N0 M110 N0*125*
*2019-05-16 18:40:21,566 - Changing monitoring state from "Connecting" to "Offline (Error: IOError: '[Errno 25] Inappropriate ioctl for device' @ comm.py:_readline:2739)"*
*2019-05-16 18:40:21,593 - Connection closed, closing down monitor*

octoprint log:

*2019-05-16 18:18:47,339 - octoprint.util.comm - INFO - Changing monitoring state from "Offline" to "Opening serial port"*
*2019-05-16 18:18:47,386 - octoprint.util.comm - INFO - Changing monitoring state from "Opening serial port" to "Connecting"*
*2019-05-16 18:18:47,421 - octoprint.util.comm - INFO - M110 detected, setting current line number to 0*
*2019-05-16 18:18:47,429 - octoprint.util.comm - ERROR - Unexpected error while reading from serial port*
*Traceback (most recent call last):*
*  File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 2739, in _readline*
*    ret = self._serial.readline()*
*  File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 4828, in readline*
*    data += bytearray(self.read(self.in_waiting))*
*  File "/home/pi/oprint/local/lib/python2.7/site-packages/serial/serialposix.py", line 467, in in_waiting*
*    s = fcntl.ioctl(self.fd, TIOCINQ, TIOCM_zero_str)*
*IOError: [Errno 25] Inappropriate ioctl for device*
*2019-05-16 18:18:47,463 - octoprint.util.comm - INFO - Changing monitoring state from "Connecting" to "Offline (Error: IOError: '[Errno 25] Inappropriate ioctl for device' @ comm.py:_readline:2739)"*
*2019-05-16 18:29:46,815 - octoprint.server.heartbeat - INFO - Server heartbeat <3*
*2019-05-16 18:34:48,890 - tornado.access - WARNING - 404 GET /dryrun-activated (::ffff:192.168.178.57) 74.97ms*

I have no idea, please can anyone help me?
Many thanks in advance,
John

You might want to search the forum for either "Raspberry Pi Zero" or "Prusa" to see what others have to say:

  • The Zero is under-powered for OctoPrint since it only has a single core
  • Yes, we know that your manufacturer told you to do this; he's still wrong
  • The Pi has two UARTs: a good one and a cheap one; you'd need to disable anything that tries to use the good one if you're attempting to do serial-over-GPIO pins

Thank you for your reply OutsourcedGuru. Can you give me more information about disabeling things that tries to use the good one please? I am not sure what to do. Serial-over-GPIO pins means the pi on the Einsy board?

Another post where I include two links at the bottom.

Foosel on the subject of using a Zero with a Prusa.

Many thanks OutsourcedGuru.