Lenovo ThinkPad T480

From ArchWiki

This article or section does not follow the Laptop page guidelines.

Reason: Missing an Accessibility section and proper function key table. (Discuss in Talk:Lenovo ThinkPad T480)
Hardware PCI/USB ID Working?
GPU (Intel) 8086:5917 Yes
GPU (NVIDIA) 10de:1d10 Yes
Ethernet 8086:15d7 Yes
Wireless 8086:24fd Yes
Audio 8086:9d71 Yes
TrackPoint PS/2 Yes
Touchpad 001d:06cb Yes
Webcam 0c45:6366 Yes
Bluetooth 8087:0a2b Yes
Smart Card reader 058f:9540 Yes
Mobile internet 2cb7:0210 Yes
Mobile internet 8086:7360 No¹
Fingerprint Sensor 06cb:009a Yes²
  1. No working Linux driver for Fibocom L850-GL. See this thread and this thread for more info.
  2. Supported on Kernel 5.8.1 with libfprint-tod-git. See this Reddit thread for more info.

This article covers the installation and configuration of Arch Linux on a Lenovo T480 laptop. Everything seems to work pretty much out the box.

For a general overview of laptop-related articles and recommendations, see Laptop.

TrackPoint and Touchpad

TrackPoint and Touchpad work out of the box and do not seem to have the same issues as the X1 Carbon Gen 6.

However one could benefit from having greatly increased event reporting frequency by enabling psmouse kernel module option synaptics_intertouch=1.

This can be made permanent with:

/etc/modprobe.d/psmouse.conf
options psmouse synaptics_intertouch=1

For two-finger scrolling activity this gives a boost from 40 Hz to 135 Hz on average which is more than threefold increase. This boost greatly contributes to the Desktop environment scrolling performance and smoothness.

(evhz-gitAUR) may be of use to find out how frequently Touchpad reports events. For example after enabling said option:

# evhz
Press CTRL-C to exit.
...
^C
Average for Synaptics TM3276-022:   137Hz

Note that units adorned with the "glass Touchpad mod" [1] [2] will not benefit from the elevated Touchpad performance with the procedure above. Running evhz will also indicate a different Touchpad identifier:

# evhz
...
Average for Synaptics TM3625-010:    42Hz

Power management/Throttling issues

Due to missing Intel Dynamic Platform and Thermal Framework (DPTF) support for Linux, a feature which should detect whether the laptop is used on a desk or on the lap so it can throttle the CPU in the latter case to reduce the temperature is not working and the CPU is always throttled. An Lenovo employee explained the situation and the solution Lenovo is building in a PDF posted in their forum (archive.org backup of the PDF). The firmware and EFI fixes have been released for a different model and Lenovo has recognized that the T480 is affected, so there is hope the T480 will get the fix too.

An interim fix is throttled (Github).

Also see:

CPU stuck at minimum frequency

A signal called BD PROCHOT inside the laptop can force the CPU to the lowest power state (400 MHz in case of the T470s) regardless of the governor. This is meant to protect the system and can be triggered by many reasons -- the CPU temperature rising above 60 °C, using a third party battery... Luckily, it can be ignored by writing a value to a register [3]. This script is an alternative to the app ThrottleStop on Windows. Install msr-tools and execute this script after every boot (or make a systemd Oneshot service).

/usr/local/bin/throttlestop
#!/bin/bash
# Disable BD PROCHOT signal on ThinkPads to prevent throttling the CPU to min. freq.
modprobe msr
reg="$(rdmsr -d 0x1FC)"         # commands rdmsr and wrmsr provided by msr-tools on Arch
if [ $((reg%2)) -eq 1 ]; then   # basically reg & 0xFFFE
	wrmsr 0x1FC $((reg-1))
fi

Firmware

Lenovo provides firmware updates for this device through the Linux Vendor Firmware Service (LVFS).

Available updates and changelogs can be found on the LVFS website. These include security patches for the Intel Management Engine and the system firmware.

The updates can be installed using fwupd.

Screen backlight

Without the intel driver (xf86-video-intel), neither xbacklight or xrandr brightness control are working.

However, the package acpilight provides a drop-in replacement for xbacklight. Apart from installing the package (which conflicts with xorg-xbacklight), you have to add your user to the video group and add the following udev rule:

/etc/udev/rules.d/90-backlight.rules
SUBSYSTEM=="backlight", ACTION=="add", \
  RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness", \
  RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"

SUBSYSTEM=="leds", ACTION=="add", KERNEL=="*::kbd_backlight", \
  RUN+="/bin/chgrp video /sys/class/leds/%k/brightness", \
  RUN+="/bin/chmod g+w /sys/class/leds/%k/brightness"

This allows you to control the backlight with xbacklight command provided by acpilight, as well as control the various LEDs on your T480.

Encryption and keyboard

Assuming encrypted installation, during boot process you are prompted to enter password to decrypt disk. In some cases you may not be able to enter password, because at this time keyboard driver is not loaded yet.

To fix this, add the atkbd module to the mkinitcpio MODULES array:

/etc/mkinitcpio.conf
MODULES = (... atkbd)

Regenerate the initramfs afterwards.

Fingerprint reader

Install python-validityAUR and register fingerprints with:

$ fprintd-enroll

Refer, for example, to the entry on fingerprint sensor of the similar Lenovo ThinkPad X270 for general procedures if list_devices failed is returned.

Function keys

The factual accuracy of this article or section is disputed.

Reason: KEY_KEYBOARD is still not supported (Discuss in Talk:Lenovo ThinkPad T480)

Some special buttons are not supported by X server due to keycode number limit. Certain keys are also handled by other devices other than the keyboard.

Key Visible? Marked? Keycode1 Effect2 Device
Fn Yes Yes KEY_WAKEUP XF86WakeUp AT Translated Set 2 Keyboard
Fn+Esc No Yes Toggles Fn Lock AT Translated Set 2 Keyboard
Fn+F1 Yes Yes KEY_MUTE XF86AudioMute AT Translated Set 2 Keyboard
Fn+F2 Yes Yes KEY_VOLUMEDOWN XF86AudioLowerVolume AT Translated Set 2 Keyboard
Fn+F3 Yes Yes KEY_VOLUMEUP XF86AudioRaiseVolume AT Translated Set 2 Keyboard
Fn+F4 Yes Yes KEY_F20 XF86AudioMicMute Thinkpad Extra Buttons
Fn+F5 Yes Yes KEY_BRIGHTNESSDOWN XF86MonBrightnessDown Video Bus
Fn+F6 Yes Yes KEY_BRIGHTNESSUP XF86MonBrightnessUp Video Bus
Fn+F7 Yes Yes KEY_SWITCHVIDEOMODE XF86Display Thinkpad Extra Buttons
Fn+F8 Yes Yes KEY_WLAN XF86WLAN Thinkpad Extra Buttons
Fn+F9 Yes Yes KEY_CONFIG XF86Tools Thinkpad Extra Buttons
Fn+F10 Yes Yes KEY_BLUETOOTH XF86Bluetooth Thinkpad Extra Buttons
Fn+F11 Yes Yes KEY_KEYBOARD XF86Keyboard ThinkPad Extra Buttons
Fn+F12 Yes Yes KEY_BOOKMARKS XF86Favorites ThinkPad Extra Buttons
Fn+PrtSc Yes No KEY_PROG2 XF86Launch2 Thinkpad Extra Buttons
Fn+B Yes No KEY_PAUSE Break AT Translated Set 2 Keyboard
Fn+K Yes No *** Scroll_Lock AT Translated Set 2 Keyboard
Fn+P Yes No KEY_PAUSE Pause AT Translated Set 2 Keyboard
Fn+S Yes No KEY_SYSRQ Sys_Req AT Translated Set 2 Keyboard
Fn+LeftArrow Yes No KEY_HOME Home AT Translated Set 2 Keyboard
Fn+RightArrow Yes No KEY_END End AT Translated Set 2 Keyboard
Fn+4 Yes No KEY_SLEEP XF86Sleep Thinkpad Extra Buttons
Fn+Spc No Yes Toggles Keyboard Backlight
  1. As reported by Libinput
  2. As reported by Wayland Event Viewer

Special buttons

See Laptop/Lenovo#Special buttons.