Troubleshooting USB Forwarding

This page covers common issues with USB device forwarding. If you encounter a problem not listed here, please check the general troubleshooting section or contact support.

Linux Linux

A Forwarded Device Never Reaches the Remote Computer

Symptom:

On a Linux remote computer, no forwarded device ever arrives. The Connect action appears to succeed, but the device is absent from the remote computer.

Root Cause:

The vhci-hcd kernel module is not loaded on the remote computer. This module is the virtual USB controller that forwarded devices attach to. Three situations leave it missing:

  • The Agent install script could not obtain a module for the running kernel.

  • The remote computer is an Autodesk workstation (Flame, Flare, Flame Assist, Lustre), where the module is not installed unless --force-usb is passed.

  • Secure Boot is enabled. The modules are unsigned, so the kernel refuses to load them.

Solution:

  1. Check that the module is loaded:

    • Run lsmod | grep vhci_hcd on the remote computer

    • If no line is printed, the module is not loaded

  2. Install the module:

    • Try sudo modprobe vhci-hcd first

    • If that fails, re-run the Agent install script for your distribution, which installs the module. See USB forwarding on Linux

    • On an Autodesk workstation, add --force-usb to the install command

  3. Check Secure Boot:

    • Run mokutil --sb-state on the remote computer

    • When it reports SecureBoot enabled, the unsigned modules cannot load. USB forwarding then requires Secure Boot to be disabled, or the modules to be signed with a key enrolled on the machine

Once vhci-hcd is loaded, restart reemod and try the USB forwarding again.

USB Device Not Appearing in the USB Menu

Symptom:

On a Linux remote computer, the expected USB device doesn’t appear in the USB menu, or forwarding fails silently.

Root Cause:

reemod failed to install the virtual USB driver, usually because the uinput kernel module isn’t enabled on the remote machine.

Solution:

  1. Check the Reemo Agent version:

    • Check the Update page and rerun the install script for your distribution to make sure you have the latest version

  2. Check that the uinput kernel module is loaded:

    • Run lsmod | grep uinput on the remote computer

    • If no line is printed, the module isn’t loaded

  3. Load the module and make it persistent:

    • Load it manually with sudo modprobe uinput

    • Make sure it’s loaded at boot (for example via /etc/modules-load.d/)

Once the uinput module is active, restart reemod and try the USB forwarding again.

USB Forwarding Stopped After a Kernel Update

Symptom:

USB forwarding used to work on a Linux remote computer and stopped, with no change made to Reemo. A kernel update or a DKU upgrade took place in between.

Root Cause:

The vhci-hcd module is built for one exact kernel version. Once the machine boots on a different kernel, the module no longer matches and is not loaded.

Solution:

  1. Re-run the Agent install script for your distribution:

    • It obtains a module for the new running kernel. See USB forwarding on Linux

    • On an Autodesk workstation, add --force-usb

  2. If no module is published for the new kernel:

    • The install script reports it and the installation continues without USB forwarding

    • Contact support with the output of uname -r taken on the remote computer

Forwarding a Graphics Tablet Crashes the Remote Computer

Symptom:

On a Linux remote computer running Enterprise Linux (RHEL, Rocky Linux, AlmaLinux), forwarding a Wacom or Cintiq graphics tablet freezes or reboots the remote computer while the device is being connected.

Root Cause:

The tablet driver of Enterprise Linux kernels older than el9_7 fails while the forwarded tablet is being enumerated. The defect is in the kernel driver and not in Reemo; it was corrected in el9_7.

Solution:

  1. Check the kernel version of the remote computer:

    • Run uname -r. A kernel tagged el9_0 through el9_6 is affected

  2. Use an el9_7 kernel or newer on the remote computer:

    • On an Autodesk Flame station the kernel is pinned by the DKU release, so this depends on Autodesk shipping a DKU based on el9_7 or newer

    • Connect the tablet directly to the remote computer in the meantime

Other devices, such as storage, mice, keyboards and dongles, forward normally on these kernels.

Windows Windows

USB Device Not Appearing in the USB Menu

Symptom:

On a Windows remote computer, the expected USB device doesn’t appear in the USB menu, or an error is shown when opening the menu.

Root Cause:

The Reemo virtual USB driver, normally installed automatically with the Agent, isn’t correctly installed on the remote machine.

Solution:

  1. Check the driver status:

  2. Reinstall the Reemo Agent if needed:

    • Reinstalling the Agent also reinstalls the virtual USB driver

macOS macOS

USB Device Not Appearing in the USB Menu

Symptom:

On a macOS remote computer, the expected USB device doesn’t appear in the USB menu.

Root Cause:

USB forwarding on macOS requires a recent version of the Reemo Agent.

Solution:

  1. Check the Agent version:

  2. Reinstall the Reemo Agent if the version is outdated:

    • Check the Installation page and reinstall the Agent to get the latest version available

Once the Agent is up to date, restart your Reemo session and try the USB forwarding again.