FnLk switcher for ThinkPad Compact Keyboards with TrackPoint
The Lenovo Thinkpad Compact Keyboard with TrackPoint is a repackaging of a Thinkpad laptop keyboard into a stand-alone case with a Bluetooth wireless or cabled USB connection to the computer. Following the current fashion, Lenovo has made the top row of keys serve two purposes, using them for both the traditional Fn keys and for "hotkeys" intended to control various functions such as volume and screen brightness.
Pressing FnLk (Fn+Esc) switches these keys between generating Fn keypresses and hotkey keypresses, but unlike laptop keyboards this mode change is handled not by the keyboard itself but by Lenovo's keyboard driver for Windows.
This repository contains some utilities that can configure the keyboards, although largely of historical interest now support is baked into Linux.
Toggling FnLk
Linux
Linux kernels 3.17 and above have support for toggling Fn-Lock in the hid-lenovo module. This means all keys should work out the box, and you can control whether fn_lock is enabled by:
echo 0 > /sys/bus/hid/devices/*17EF\:604*/fn_lock
The kernel can't currently switch fn_lock automatically for you, however you can use esekeyd to map KEY_FN_ESC to a script such as:
{ grep -q 1 /sys/bus/hid/devices/*17EF\:604*/fn_lock && echo 0 || echo 1; } \
> /sys/bus/hid/devices/*17EF\:604*/fn_lock
...to toggle it.
Apple OS X (MacOS)
tpkb is a Mac userland tool
similar to tp-compact-keyboard. It uses the cross-platform hidapi
library.
Linux Pre-3.17
Use either the tp-compact-bt-keyboard or the tp-compact-usb-keyboard utilities in this repository, or apply the kernel-patches to your kernel.
Disable FnLk by default
Linux assumes you want Fn keys to act as Fn keys and Enables Fn-Lock, however you may want the opposite.
Thinkpad TrackPoint Keyboard II is in Linux kernel 5.19 and greater.
If so create a udev rule with the following command:
#Creates udev rules file
cat <<'EOF' > /etc/udev/rules.d/99-thinkpad-trackpoint-disable-fn-lock.rules
#ThinkPad TrackPoint Keyboard I & II USB
SUBSYSTEM=="hid", \
DRIVER=="lenovo", \
ATTRS{idVendor}=="17ef", ATTRS{idProduct}=="6047|60ee", \
ATTR{fn_lock}="0"
#ThinkPad TrackPoint Keyboard I & II Bluetooth
SUBSYSTEM=="input", \
ATTRS{id/vendor}=="17ef", ATTRS{id/product}=="6048|60e1", \
TEST=="/sys/$devpath/device/fn_lock", \
RUN+="/bin/sh -c 'echo 0 > \"/sys/$devpath/device/fn_lock\"'"
EOF
#Run commands to reload udev
udevadm control --reload-rules && udevadm trigger
How I Did It
I worked out the custom commands by sniffing what the Windows driver did.
First I set up a Windows XP virtual machine in KVM/QEMU and installed the drivers. Then I
disconnected the keyboard from my computer and ensured that the user running
QEMU could write to the /dev/bus/usb node associated with my Bluetooth
dongle.
Wireshark was readied for capture:
# modprobe usbmon
# wireshark
Then, I let Windows use the Bluetooth dongle:
(qemu) usb_add host:0a5c:217f
If you capture the whole association process then you should be able to view
HID packets to/from the keyboard (filter for bthid). The particuarly
interesting ones here are the ones going to the keyboard.
Disassembling the Keyboard
The upper part of the keyboard case is just clipped on; run something around the seam on the underside of the keyboard to release it. The keyboard itself is fastened to the lower part of the case with double-sided tape. Very gentle persuasion (probably some heat too) removes it.
The keyboard itself looks like it comes out of a Thinkpad, with metal plates stuck to it to add heft. The keyboard connects to a controller board in the top right.
Images of USB keyboard internals Images of BT keyboard internals
Repairing the Trackpoint
Some users of the Bluetooth keyboard have found that the TrackPoint stops working whilst the rest of the keyboard is fine. This isn't a software issue; apparently the chip that controls the TrackPoint isn't correctly soldered down.
See: http://bdm.cc/2016/06/lenovo-bluetooth-keyboard-repairs/
Replacement trackpoint caps
The keyboards use the "ThinkPad Low Profile TrackPoint Caps" (FRU 0A33908 for a 10-pack) by default. The original-size will fit also, but stick out more. This is fine for the cat-tongue, but with the others your finger can catch the edge.
Other keyboards
Some notes on other keyboards, not currently supported: