What is Evdev, and what does it do?
Evdev, short for “Event Device”, is a Linux input driver that supports almost all input devices, including keyboards, mice, game controllers, and tablets. It takes the raw input events from these devices and turns them into accessible files in the /dev/input/ directory. These files can be then accessed to get input from such input devices. It is considered a type of Character Device Driver, which turns raw data (in bytes) into files.
Evdev is how Linux communicates with and gets the raw data from these input devices. In our use case, we will use it to passthrough these input devices into our virtual machine and configure a keyboard shortcut to allow sharing of devices as we choose.
Finding our keyboard and mouse
Make sure your keyboard and mouse are plugged in and detected in Linux.
Let’s check the input devices currently in use. Enter the following command into the terminal:
ls /dev/input/by-id
Example output:
usb-30fa_USB_Optical_Mouse-event-mouse
usb-30fa_USB_Optical_Mouse-mouse
usb-EVGA_Z12_Gaming_Keyboard-event-if01
usb-EVGA_Z12_Gaming_Keyboard-event-kbd
usb-EVGA_Z12_Gaming_Keyboard-if01-event-mouse
usb-EVGA_Z12_Gaming_Keyboard-if01-mouse
usb-EVGA_Z12_Gaming_Keyboard-if02-event-kbd
Only devices that have event in their names can be passed through. In the example output, the only devices that could be passed through would be
usb-30fa_USB_Optical_Mouse-event-mouse
usb-EVGA_Z12_Gaming_Keyboard-event-if01
usb-EVGA_Z12_Gaming_Keyboard-event-kbd
usb-EVGA_Z12_Gaming_Keyboard-if01-event-mouse
usb-EVGA_Z12_Gaming_Keyboard-if02-event-kbd
Now, we need to figure out which devices should be passed through. For each file in the output, check the contents via cat. For instance:
Remember to Control-C out of the process after!
cat /dev/input/by-id/usb-30fa_USB_Optical_Mouse-event-mouse
Move your cursor or type something on your keyboard. If the terminal spits out garbled characters, that is the correct device. If not, try the other devices in the list.
Now that you have the two devices, note the paths of these input devices. These will be the devices that we will pass through to our virtual machine.