Matching for Lenovo UltraNav devices is too general in quirks file
Following your call to test the new trackpoint acceleration I installed libinput-1.11.902-201808160257gitc476524a and it seems my (old!) Lenovo keyboard is matching this entry in 50-system-lenovo.quirks:
[Lenovo UltraNav SK-8845 (USB keyboard) Trackpoint]
MatchBus=usb
MatchVendor=0x06CB
MatchProduct=0x0009
AttrTrackpointMultiplier=2.5
but this multiplier makes it way too fast. It seems that for my device, the default multiplier works just fine. So, perhaps the match rules need to be adjusted to match on something more that just vendor and product. Here's my device's udev info (I believe mouse0 is the touchpad and mouse1 is the trackpoint):
$ udevadm info /sys/class/input/mouse0
P: /devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1.4/3-1.4:1.0/input/input10/mouse0
N: input/mouse0
S: input/by-id/usb-Synaptics_Inc._Composite_TouchPad___TrackPoint-mouse
S: input/by-path/pci-0000:00:14.0-usb-0:1.4:1.0-mouse
E: DEVLINKS=/dev/input/by-id/usb-Synaptics_Inc._Composite_TouchPad___TrackPoint-mouse /dev/input/by-path/pci-0000:00:14.0-usb-0:1.4:1.0-mouse
E: DEVNAME=/dev/input/mouse0
E: DEVPATH=/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1.4/3-1.4:1.0/input/input10/mouse0
E: ID_BUS=usb
E: ID_INPUT=1
E: ID_INPUT_TOUCHPAD=1
E: ID_MODEL=Composite_TouchPad___TrackPoint
E: ID_MODEL_ENC=Composite\x20TouchPad\x20\x2f\x20TrackPoint
E: ID_MODEL_ID=0009
E: ID_PATH=pci-0000:00:14.0-usb-0:1.4:1.0
E: ID_PATH_TAG=pci-0000_00_14_0-usb-0_1_4_1_0
E: ID_REVISION=0020
E: ID_SERIAL=Synaptics_Inc._Composite_TouchPad___TrackPoint
E: ID_TYPE=generic
E: ID_USB_DRIVER=synaptics_usb
E: ID_USB_INTERFACES=:030102:000000:
E: ID_USB_INTERFACE_NUM=00
E: ID_VENDOR=Synaptics_Inc.
E: ID_VENDOR_ENC=Synaptics\x20Inc.
E: ID_VENDOR_ID=06cb
E: MAJOR=13
E: MINOR=32
E: SUBSYSTEM=input
E: USEC_INITIALIZED=2781322
$ udevadm info /sys/class/input/mouse1
P: /devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1.4/3-1.4:1.1/input/input11/mouse1
N: input/mouse1
S: input/by-id/usb-Synaptics_Inc._Composite_TouchPad___TrackPoint-if01-mouse
S: input/by-path/pci-0000:00:14.0-usb-0:1.4:1.1-mouse
E: DEVLINKS=/dev/input/by-path/pci-0000:00:14.0-usb-0:1.4:1.1-mouse /dev/input/by-id/usb-Synaptics_Inc._Composite_TouchPad___TrackPoint-if01-mouse
E: DEVNAME=/dev/input/mouse1
E: DEVPATH=/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1.4/3-1.4:1.1/input/input11/mouse1
E: ID_BUS=usb
E: ID_INPUT=1
E: ID_INPUT_MOUSE=1
E: ID_INPUT_POINTINGSTICK=1
E: ID_MODEL=Composite_TouchPad___TrackPoint
E: ID_MODEL_ENC=Composite\x20TouchPad\x20\x2f\x20TrackPoint
E: ID_MODEL_ID=0009
E: ID_PATH=pci-0000:00:14.0-usb-0:1.4:1.1
E: ID_PATH_TAG=pci-0000_00_14_0-usb-0_1_4_1_1
E: ID_REVISION=0020
E: ID_SERIAL=Synaptics_Inc._Composite_TouchPad___TrackPoint
E: ID_TYPE=generic
E: ID_USB_DRIVER=synaptics_usb
E: ID_USB_INTERFACES=:030102:000000:
E: ID_USB_INTERFACE_NUM=01
E: ID_VENDOR=Synaptics_Inc.
E: ID_VENDOR_ENC=Synaptics\x20Inc.
E: ID_VENDOR_ID=06cb
E: MAJOR=13
E: MINOR=33
E: SUBSYSTEM=input
E: USEC_INITIALIZED=2781387
and here's how libinput sees it:
Device: Synaptics Inc. Composite TouchPad / TrackPoint
Kernel: /dev/input/event6
Group: 6
Seat: seat0, default
Size: 70x51mm
Capabilities: pointer
Tap-to-click: disabled
Tap-and-drag: enabled
Tap drag lock: disabled
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: *two-finger edge
Click methods: none
Disable-w-typing: n/a
Accel profiles: none
Rotation: n/a
Device: Synaptics Inc. Composite TouchPad / TrackPoint (Stick)
Kernel: /dev/input/event7
Group: 6
Seat: seat0, default
Capabilities: pointer
Tap-to-click: n/a
Tap-and-drag: n/a
Tap drag lock: n/a
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: disabled
Calibration: n/a
Scroll methods: *button
Click methods: none
Disable-w-typing: n/a
Accel profiles: flat *adaptive
Rotation: n/a