# Changing keycodes on the hardware level Topics: [[Linux]], [[Hardware]] ## Subtopics - ## Procedure Test the keycodes for the affected device: ```shell $ sudo evtest No device specified, trying to scan all of /dev/input/event* Available devices: /dev/input/event0: Sleep Button /dev/input/event1: Power Button /dev/input/event10: HDA Intel PCH Headphone /dev/input/event11: HDA Intel PCH HDMI/DP,pcm=3 /dev/input/event12: HDA Intel PCH HDMI/DP,pcm=7 /dev/input/event13: HDA Intel PCH HDMI/DP,pcm=8 /dev/input/event14: HDA Intel PCH HDMI/DP,pcm=9 /dev/input/event15: solaar-keyboard /dev/input/event2: Lid Switch /dev/input/event3: AT Translated Set 2 keyboard /dev/input/event4: UNIW0001:00 093A:0255 Mouse /dev/input/event5: UNIW0001:00 093A:0255 Touchpad /dev/input/event6: Video Bus /dev/input/event7: Intel HID events /dev/input/event8: PC Speaker /dev/input/event9: HDA Intel PCH Mic Select the device event number [0-15]: 3 Input driver version is 1.0.1 Input device ID: bus 0x11 vendor 0x1 product 0x1 version 0xab83 Input device name: "AT Translated Set 2 keyboard" Supported events: Event type 0 (EV_SYN) Event type 1 (EV_KEY) Event code 1 (KEY_ESC) Event code 2 (KEY_1) Event code 3 (KEY_2) ... Testing ... (interrupt to exit) Event: time 1705661747.729527, type 4 (EV_MSC), code 4 (MSC_SCAN), value 1c Event: time 1705661747.729527, type 1 (EV_KEY), code 28 (KEY_ENTER), value 0 Event: time 1705661747.729527, -------------- SYN_REPORT ------------ Event: time 1705661750.396236, type 4 (EV_MSC), code 4 (MSC_SCAN), value 3a Event: time 1705661750.396236, type 1 (EV_KEY), code 58 (KEY_CAPSLOCK), value 1 Event: time 1705661750.396236, -------------- SYN_REPORT ------------ Event: time 1705661750.396491, type 17 (EV_LED), code 1 (LED_CAPSL), value 1 Event: time 1705661750.396491, -------------- SYN_REPORT ------------ Event: time 1705661750.518530, type 4 (EV_MSC), code 4 (MSC_SCAN), value 3a Event: time 1705661750.518530, type 1 (EV_KEY), code 58 (KEY_CAPSLOCK), value 0 Event: time 1705661750.518530, -------------- SYN_REPORT ------------ Event: time 1705661752.453338, type 4 (EV_MSC), code 4 (MSC_SCAN), value 1d Event: time 1705661752.453338, type 1 (EV_KEY), code 29 (KEY_LEFTCTRL), value 1 Event: time 1705661752.453338, -------------- SYN_REPORT ------------ Event: time 1705661752.616397, type 4 (EV_MSC), code 4 (MSC_SCAN), value 1d Event: time 1705661752.616397, type 1 (EV_KEY), code 29 (KEY_LEFTCTRL), value 0 Event: time 1705661752.616397, -------------- SYN_REPORT ------------ ``` The relevant scan code (`EV_MSC`) for Caps Lock is 3a. Get the modalias values for the internal keyboard: ```shell $ cat /sys/class/input/event3/device/modalias | sudo tee /etc/udev/hwdb.d/10-internal-keyboard.hwdb input:b0011v0001p0001eAB83-e0,1,4,11,14,k71,72,73,74,75,76,77,79,7A,7B,7C,7D,7E,7F,80,8C,8E,8F,9B,9C,9D,9E,9F,A3,A4,A5,A6,AC,AD,B7,B8,B9,D9,E2,ram4,l0,1,2,sfw ``` Use this information to create a new file `/etc/udev/hwdb.d/10-internal-keyboard.hwdb`. The modalias line has to be prefixed with `evdev:` and can be shortened with a wildcard character. Add a line to remap the keyboard scan code. Result: ```plain evdev:input:b0011v0001p0001* KEYBOARD_KEY_3a=leftctrl ``` The device ID can change, presumably after kernel updates. If that happens, cut the ID with the asterisk further to the left. Finally, enable the change: ```shell $ sudo systemd-hwdb update $ sudo udevadm trigger ``` ## Bookmarks - [How to remap 'Caps\_Lock' key to 'w' in Wayland - Ask Ubuntu](https://askubuntu.com/a/1289317/26913) ## Related topics -