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# Lenovo ThinkPad T480s

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Reason: Needs IDs added to hardware table and a function keys section should be added (Discuss in Talk:Lenovo ThinkPad T480s)

Hardware | PCI/USB ID | Working?
--- | --- | ---
GPU |  | Yes
Wireless |  | Yes
Audio |  | Yes
TrackPoint |  | Yes
Touchpad |  | Yes
Webcam |  | Yes
Fingerprint reader |  | Yes
Mobile broadband |  | Yes
Bluetooth |  | Yes
Smartcard reader |  | Yes
PrivacyGuard |  | Yes

This article covers the installation and configuration of Arch Linux on a Lenovo T480s laptop. For the most part things work out-of-the-box, but there are some features that are unavailable.

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

## Powersaving

Without special configuration and with default firmware settings, power usage is a bit high (around 7,5W in idle). There are a few knobs to improve battery life:

Warning: Changing Thunderbolt BIOS options has been reported to irreversibly brick ThinkPads [1] [2] [3]. This is a BIOS bug. Until there is more information available on that matter (or a fix underway), use these options with care.

- Set "Thunderbolt BIOS Assist Mode" to "Enabled" in the EFI firmware interface. This seems to reduce number of idle wakeups.
  - However, kernel versions since 4.19+ should support it natively ([4]), and some power consumption improvements is reported if this is switched to "Disabled" [5].
- Disable unused peripherals under "Security" -> "I/O port access" in the firmware. This especially applies to the SD/MMC-cardreader, which seems to drain some power even when idle

As of Kernel 4.15, DisplayPort PSR (Panel self refresh) is disabled by default and broken when forcibly enabled (system hangs after a few seconds, display lag). 4.17-rc1 seems to improve a lot in this regard, but PSR still sometimes causes the screen to freeze for a few seconds.

### SD card reader

According to various reports the SD card reader drains several watts of power. If you do not want to disable it in bios because you use it semi-regularly, you can turn it off by unbinding its driver using this command:

    # tee /sys/bus/usb/drivers/usb/unbind <<< 2-3

You can then turn the reader back on by running:

    # tee /sys/bus/usb/drivers/usb/bind <<< 2-3

## Fingerprint reader

The fingerprint sensor `06cb:009a` is not supported by libfprint.

There is a project python-validity based on open-fprintd that support `06cb:009a` see [6].

Warning: Some issues or delay are known after `suspend/resume`. See Fingerprint not working after waking up from suspend in the README to resolve this issue.

Install the python-validityAUR or python-validity-gitAUR and enroll your device:

    $ fprintd-enroll

Refer to Fprint#Configuration for configuration.

## Troubleshooting

### Thermal throttling

There are reported throttling issues for Lenovo T480/T480s/X1C6 notebooks.[7]

This script forces the CPU package power limit (PL1/2) to 44 W (29 W on battery) and the temperature trip point to 95 'C (85 'C on battery) by overriding default values in MSR and MCHBAR every 5 seconds (30 on battery) to block the Embedded Controller from resetting these values to default.

Install the throttled package and enable the `lenovo_fix.service`.[8]

It is recommended to also undervolt the CPU (Undervolting CPU#intel-undervolt). Most Kaby Lake R chips are able to easily undervolt to -100mV or more, which significantly helps to keep the device from thermal throttling. Throttled also provides undervolting capabilities and will overwrite the undervolt settings applied by intel-undervolt when it updates settings if both services are enabled.

### PrivacyGuard

The PrivacyGuard feature is referred to as LCD Shadow [9] and was introduced in Linux 5.4.[10]

To enable or turn on the LCD shadow:

    # tee /proc/acpi/ibm/lcdshadow <<< 1

Conversely, use `0` to disable it:

    # tee /proc/acpi/ibm/lcdshadow <<< 0

### Fix freezes/hangs on QT applications (with Intel driver)

See Intel graphics#AccelMethod.

### Fix frequent WiFi disconnects

The iwlwifi driver provided by Linux Kernel 5.1 and later has a bug that can cause disconnects of the WiFi. If this occurs, check the system log using journalctl(1) and search for this message: "No beacon heard and the time event is over already." If you see this message, try some of the suggested fixes discussed on Bug 203709. Workarounds discussed in the thread include:

1. Modifying kernel module parameter by adding a new configuration file for modprobe.d(5):

    /etc/modprobe.d/mac80211.conf

    options mac80211 beacon_loss_count=1000 probe_wait_ms=75
    options ath9k debug=0xffffffff btcoex_enable=0 ps_enable=0 use_msi=0

2. Disabling IPv6

3. Applying the kernel patch linux-beaconAUR and creating the following kernel module parameter for modprobe.d(5):

    /etc/modprobe.d/wifi-fix.conf

    options iwlwifi beacon_timeout=256

## See also

- T480s install video playlist

Category:

- Lenovo

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