UKBD(4) BSD Kernel Interfaces Manual UKBD(4)


ukbd — USB keyboard driver


To compile this driver into the kernel, place the following line in your kernel configuration file:

device ukbd

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):



The ukbd driver provides support for keyboards that attach to the USB port. usb(4) and one of uhci(4) or ohci(4) must be configured in the kernel as well.


By default, the keyboard subsystem does not create the appropriate devices yet. Make sure you reconfigure your kernel with the following option in the kernel config file:


If both an AT keyboard USB keyboards are used at the same time, the AT keyboard will appear as kbd0 in /dev. The USB keyboards will be kbd1, kbd2, etc. You can see some information about the keyboard with the following command:

kbdcontrol -i < /dev/kbd1

or load a keymap with

kbdcontrol -l keymaps/pt.iso < /dev/kbd1

See kbdcontrol(1) for more possible options.

You can swap console keyboards by using the command

kbdcontrol -k /dev/kbd1

From this point on, the first USB keyboard will be the keyboard to be used by the console.

If you want to use a USB keyboard as your default and not use an AT keyboard at all, you will have to remove the device atkbd line from the kernel configuration file. Because of the device initialization order, the USB keyboard will be detected after the console driver initializes itself and you have to explicitly tell the console driver to use the existence of the USB keyboard. This can be done in one of the following two ways.

Run the following command as a part of system initialization:

kbdcontrol -k /dev/kbd0 < /dev/ttyv0 > /dev/null

(Note that as the USB keyboard is the only keyboard, it is accessed as /dev/kbd0) or otherwise tell the console driver to periodically look for a keyboard by setting a flag in the kernel configuration file:

device sc0 at isa? flags 0x100

With the above flag, the console driver will try to detect any keyboard in the system if it did not detect one while it was initialized at boot time.



Make the keyboards available through a character device in /dev.

makeoptions UKBD_DFLT_KEYMAP=fr.iso

The above lines will put the French ISO keymap in the ukbd driver. You can specify any keymap in /usr/share/syscons/keymaps or /usr/share/vt/keymaps (depending on the console driver being used) with this option.


Do not allow the user to change the keymap. Note that these options also affect the AT keyboard driver, atkbd(4).


The following variables are available as both sysctl(8) variables and loader(8) tunables:


Debug output level, where 0 is debugging disabled and larger values increase debug message verbosity. Default is 0.


blocking device nodes


device ukbd

Add the ukbd driver to the kernel.


kbdcontrol(1), ohci(4), syscons(4), uhci(4), usb(4), vt(4), config(8)


The ukbd driver was written by Lennart Augustsson <augustss [AT]> for NetBSD and was substantially rewritten for FreeBSD by Kazutaka YOKOTA <yokota [AT]>.

This manual page was written by Nick Hibma <n_hibma [AT]> with a large amount of input from Kazutaka YOKOTA <yokota [AT]>.

BSD April 24, 2018 BSD