RFXTRX logging disables USB connection on Synology

I’ve quite a strange issue. I have moved from Domoticz to HASS and am using a Synology NAS. In the process of changing, I also upgraded my NAS from a 214+ to a 918+. Now everything looked stable at first, although I noticed after a few weeks that the RFXTRX connection had suddenly dropped. Rebooting the NAS fixed the problem. Then, I added logging statement for the RFXTRX, like this:

  default: warning
    homeassistant.components.rfxtrx: debug
    homeassistant.components.switch.rfxtrx: debug
    homeassistant.components.light.rfxtrx: debug
    homeassistant.components.sensor.rfxtrx: debug

After that, the RFXTRX dropped it’s connection after a few hours. HASS can’t find the device anymore and looking on the NAS we dmesg I get the following:

[147272.554907] usb 1-1.3-port2: disabled by hub (EMI?), re-enabling...
[147272.562020] usb 1-1.3.2: USB disconnect, device number 6
[147272.568142] ftdi_sio ttyUSB0: error from flowcontrol urb
[147272.574414] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0
[147272.583958] ftdi_sio 1-1.3.2:1.0: device disconnected
[147272.776459] usb 1-1.3.2: new full-speed USB device number 8 using xhci_hcd
[147272.885284] ftdi_sio 1-1.3.2:1.0: FTDI USB Serial Device converter detected
[147272.893195] usb 1-1.3.2: Detected FT232RL
[147272.897919] usb 1-1.3.2: FTDI USB Serial Device converter now attached to ttyUSB1

So the RFXTRX is on ttyUSB0 after start, disconnects and reconnects as ttyUSB1. Obviously, this crashes HASS. Strange thing is that I’m also using an Aeotec Z-Wave USB stick, which functions normally all of time. Does anybody have a clue whether this problem is:

  • HASS related?
  • RFXTRX related?
  • Synology related?

Please note that I added a solution to load the USB driver on the Synology NAS as was suggested in this Post