What is the problem?
We are using FTDI Serial to USB connections from the Smoothieboard v1.1 to Raspberry Pi3 to connect our printers. When upgrading to Octoprint 1.3.6 to 1.3.7, the connection no longer connects -- it simply times out. The connection is visible as /dev/ttyUSB0 but times out.
What did you already try to solve it?
I looked through the patch notes for 1.3.7 and found they discovered bug that was partially resolved associated to PySerial. I'm not sure if the FTDI Serial to USB is reliant on that module, but attempted to update to the version that was indicated as required with no changed. I also attempted to install a new Octopi image (nightly build) which included 1.3.7, but I got the same results (also attempted to update PySerial on this image after install). Using the USB out on the Smoothieboard works fine, this is limited to a UART port connection using a FTDI Serial to USB adapter (something our printers need with our configuration and setup).
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware,
serial.log or output on terminal tab, ...)
Connected to: Serial<id=0x6b5c55d0, open=True>(port='/dev/ttyUSB0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=10.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
Changing monitoring state from "Opening serial port" to "Connecting"
Send: N0 M110 N0*125
There was a timeout while trying to connect to the printer
Changing monitoring state from "Connecting" to "Offline"
Connection closed, closing down monitor