Note: This article was originally published in 2016. Some steps, commands, or software versions may have changed. Check the current Ubuntu documentation for the latest information.

Resolved: USB 3.0 Hub Not Recognizing Mouse and Keyboard in Ubuntu Linux

One of the most confusing issues when using Ubuntu Linux (especially on newer motherboards or when building a crypto mining rig) is unexpectedly losing all input. Your mouse and keyboard might work perfectly in the BIOS and on the initial GRUB boot screen, but as soon as Ubuntu boots or the installation screen reaches the “Language Selection” prompt, the USB keyboard and mouse completely freeze or stop working.

This happens frequently on systems that use USB 3.0 (blue ports) combined with modern Extensible Host Controller Interface (xHCI) setups. When the Linux kernel takes over the hardware from the BIOS, it fails to properly initialize the USB bus if the hand-off isn’t configured correctly.

Here are the step-by-step solutions to fix this, whether you are installing Ubuntu or experiencing USB hub drops on a live system.

Solution 1: BIOS / UEFI Hardware Fixes

If your keyboard and mouse die precisely when the Ubuntu graphical interface or installation wizard starts, the issue is almost certainly a BIOS hand-off problem with the USB controller. To fix it, you need to ensure the following:

  1. Replug into USB 3.0 ports: The most common fix is counter-intuitive. Unplug your mouse and keyboard from USB 2.0 (black) ports or external hubs, and plug them directly into the USB 3.0 (blue) ports on the back of the motherboard.
  2. Enable USB Legacy Support: Enter your BIOS/UEFI settings and ensure “USB Legacy Support” or “Legacy USB Support” is set to Enabled.
  3. Turn off xHCI Hand-off: In your BIOS, look for an option called “xHCI Hand-off” (sometimes under Advanced -> USB Configuration). If it is currently Enabled, disable it. If it is Disabled, try enabling it. This setting dictates whether the BIOS or the OS (Ubuntu) manages the USB 3.0 controller.

For many users, simply switching the peripherals from a front-panel USB 2.0 port back to a native USB 3.0 port on the motherboard completely resolves the freeze.

Solution 2: Fix USB recognition via Kernel Parameters (IOMMU)

If your mouse and keyboard randomly stop working while using Ubuntu, or if they are plugged into a USB 3.0 Hub that isn’t being recognized properly, you likely have an IOMMU conflict. You need to tell the Linux kernel to handle memory mapping differently.

If you can access the system (using a different keyboard, SSH, or entering GRUB recovery mode), follow these steps:

  1. Open a terminal and edit the GRUB configuration file: sudo nano /etc/default/grub
  2. Find the line that begins with GRUB_CMDLINE_LINUX_DEFAULT. It usually looks like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
  3. Add iommu=soft inside the quotes. (If you are on an AMD system, you might also try amd_iommu=on). It should look like this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash iommu=soft"
  4. Save the file (Ctrl+O, Enter) and exit (Ctrl+X).
  5. Update GRUB and reboot: sudo update-grub sudo reboot

Adding iommu=soft is the most reliable way to fix external USB hubs and multi-port adapters dropping connections or failing to recognize devices in Ubuntu.