Roto-Control MIDI Controller only partially functioning

twar2600 · 2025-12-26 22:41:41

The Roto-Control is a MIDI controller for use with Bitwig, a music DAW.
The developers provide a ROTO-SETUP-2.1.0-x64.AppImage and roto_setup.rules.

roto_setup.rules:

SUBSYSTEM=="usb", ATTR{idVendor}=="2e8a", ATTR{idProduct}=="0003", GROUP="plugdev"

If I'm not mistaken Arch doesn't use the plugdev group but rather uucp so I changed it to

SUBSYSTEM=="usb", ATTR{idVendor}=="2e8a", ATTR{idProduct}=="0003", GROUP="uucp"

I also added my user to the uucp group.

When executing the .AppImage the application opens alongside the terminal. In the terminal I see some errors but nothing looks catastrophic to my untrained eyes. This application isn't supposed be interacted with much, only run in the background while you use Bitwig. Over in Bitwig the Roto-Control partially works but only about half of the controls at any given time. And most of the time none of the controls work. I have tried to connect it to different USB-C ports on my computer. The Roto-Control is a motorized MIDI controller and communicates bidirectionally. My other MIDI controllers have worked fine but they are much simpler devices.

Output of the Roto-Setup application:

travis@archimedes ~:cd Roto
travis@archimedes Roto:./ROTO-SETUP-2.1.0-x64.AppImage
System data file: /home/travis/.config/ROTO-SETUP/system.json
Ready.
No update required for Roto-Control.bwextension
Frontend ready.
Listing serial ports:
Found {"sortKey":"/dev/ttyACM0","path":"/dev/ttyACM0"} for Atari device at location usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00:
Found {"sortKey":"/dev/ttyACM1","path":"/dev/ttyACM1"} for Atari device at location usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if02:
Not an Atari serial port: /dev/ttyS0 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS1 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS10 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS11 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS12 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS13 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS14 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS15 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS16 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS17 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS18 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS19 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS2 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS20 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS21 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS22 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS23 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS24 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS25 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS26 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS27 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS28 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS29 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS3 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS30 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS31 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS4 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS5 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS6 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS7 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS8 (vendorId: undefined, productId: undefined)
Not an Atari serial port: /dev/ttyS9 (vendorId: undefined, productId: undefined)
All serial ports have been listed.
Considering updated devices:
{
  'usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00': {
    id: 'usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00',
    paths: [ [Object] ]
  },
  'usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if02': {
    id: 'usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if02',
    paths: [ [Object] ]
  }
}
Connecting to device at usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00 ...
Connecting to main port on /dev/ttyACM0 ...
Device at usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00 has been connected.
Connected to device usb-Melbourne_Instruments_Roto-Control_E6619896572A3721-if00, version 2.1.0 (ae3bf1f)
Firmware matches bundled version v2.1.0
Atari mode: 1 - first control index: 0
Error fetching version file: Forbidden
[1089:1226/161121.856025:ERROR:gl_surface_presentation_helper.cc(260)] GetVSyncParametersIfAvailable() failed for 1 times!
[1089:1226/161122.609985:ERROR:gl_surface_presentation_helper.cc(260)] GetVSyncParametersIfAvailable() failed for 2 times!
[1089:1226/161122.624096:ERROR:gl_surface_presentation_helper.cc(260)] GetVSyncParametersIfAvailable() failed for 3 times!
Plugin set: [32 53 1d 65 04 41 2f 39]

I'm setting up an Arch music computer and so far I've gotten all of my other equipment and software to work, this is the last thing. Any help or suggestions is very much appreciated.

5hridhyan · 2025-12-28 05:32:18

It’s becuase of a bad udev rule. And Arch does not use plugdev, and switching it to uucp will be wrong, and also uucp is for generic serial access and does not reliably cover bidirectional USB MIDI devices.

/dev/ttyACM0
/dev/ttyACM1

Roto-Control exposes two CDC ACM interfaces:
ttyACM0 => main MIDI/control
ttyACM1 => motorized feedback + state sync
If either node is not writable, you get exactly what you’re seeing: partial controls, intermittent behavior, sometimes nothing works. uucp frequently leaves one of the interfaces inaccessible. That’s why this breaks.
try this:

SUBSYSTEM=="usb", ATTR{idVendor}=="2e8a", ATTR{idProduct}=="0003", GROUP="audio", MODE="0666"

Make sure the user is in audio, then Log out/in.
That ensures both /dev/ttyACM* devices are readable and writable, which is mandatory for motorized, bidirectional controllers. The AppImage messages are irrelevant Electron/Chromium noise. They have nothing to do with MIDI or device I/O. Also, plug the device directly into the machine like without any hubs.

edit:
I’ve provided guidance to the best of my knowledge. I won’t be able to follow up further, hope this will be solved Good luck!

Last edited by 5hridhyan (2026-01-28 15:57:09)

Arch Linux

#1 2025-12-26 22:41:41

Roto-Control MIDI Controller only partially functioning

#2 2025-12-28 05:32:18

Re: Roto-Control MIDI Controller only partially functioning

Board footer