Lenovo ThinkPad T490

From ArchWiki
Jump to navigation Jump to search

Tango-edit-clear.pngThis article or section does not follow the Laptop page guidelines.Tango-edit-clear.png

Reason: Hardware table needs IDs and a function keys table should be added (Discuss in Talk:Lenovo ThinkPad T490)
Hardware PCI/USB ID Working?
GPU Yes
Wireless Yes
Audio Yes
TrackPoint Yes
Touchpad Yes
Webcam 04f2:b681 Yes
Bluetooth Yes
Mobile broadband Untested
Fingerprint reader 06cb:00bd Yes
MicroSD reader Yes

FN Keys

Most FN keys should work out of the box, but if it does not, bind mentioned keys to below commands:

  • F1 button: amixer set Master toggle.
  • F2 button: amixer set Master 5%-.
  • F3 button: amixer set Master 5%+.
  • F4 button: amixer set Capture toggle.

Touchpad

Touchpad is problematic. By default, if you hold the thumb over the button area, the pointer will not move. Once the system is installed, the problem disappears when using KDE, while GNOME still exhibits the issue. In GNOME, use the following to fix the problem:

xinput set-prop 'SynPS/2 Synaptics TouchPad' 'libinput Click Method Enabled' 1 0

Even after doing this, the mouse pointer still jumps around when clicking the button sometimes.

Current systemd v245 contains broken hwdb entry that sets invalid aspect ratio for the touchpad making it behave strangely.

Fingerprint Sensor

The fingerprint sensor works with some recent firmware and software updates (2019-12-15). Driver development info: [1].

  1. Use fwupd to install the latest firmware for "Synaptics Prometheus Fingerprint Reader". The update might have to be done manually as the released firmware is in testing; or you could enable the testing remote in fwupd to allow automated upgrade. The relevant firmwares are Prometheus Fingerprint Reader and Prometheus Fingerprint Reader Configuration.
  2. Latest fprintd and libfprint are required. fprintd-libfprint2AUR and libfprint-gitAUR can be useful here.
  3. fprint has more details on how to setup the fingerprint for PAM authentication for example.

Known Issues

Extremely high battery usage because of dedicated GPU

Tip: In short, because of a device-specific quirk in how Lenovo handles ACPI calls, you need the following kernel cmdline parameter to successfully power off your dedicated GPU: acpi_osi='!Linux-Lenovo-NV-HDMI-Audio'.

If your laptop is equipped with a Nvidia dedicated GPU (such as the GeForce MX250), you will likely encounter very high battery usage because the GPU will not turn off.

You can check the "power state" of the dedicated gpu with the following, where you need to change "3c:00.0" with the PCI BusID of your GPU you get from lspci | grep -i nvidia:

cat /sys/bus/pci/devices/0000:3c:00.0/firmware_node/power_state

Power state 'D0' means your GPU is consuming a lot of power right now Power states 'D3hot' and 'D3cold' are the low-power modes where the GPU is basically turned off.

The following steps are required to fix this issue:

  • Make sure to have the following inside file /etc/X11/nvidia-xorg.conf, where the ID after "PCI:" (60 in the example above) will be the output you get from lspci | grep -i nvidia, converted from hex to decimal (e.g., from 3c to 60):
Section "Device"
  Identifier "nvidia"
  Driver "nvidia"
  BusID "PCI:60:0:0"
EndSection
  • Load the bbswitch module at boot by running echo bbswitch | sudo tee /etc/modules-load.d/bbswitch.conf
  • Important: Edit /etc/default/grub and add acpi_osi='!Linux-Lenovo-NV-HDMI-Audio' to the kernel command line parameters. This article has a short explaination why. Remember to regenerate grub.cfg by running sudo grub-mkconfig -o /boot/grub/grub.cfg (change the path depending on where your boot partition is), and reboot. This step is required because of a Lenovo bug in how they handle ACPI calls, which bbswitch relies on to power on/off your GPU.
  • You can now turn on/off the dedicated GPU by running the following as root
tee /proc/acpi/bbswitch <<<OFF
tee /proc/acpi/bbswitch <<<ON

Check the power status of the GPU by running cat /proc/acpi/bbswitch.

Remember: bbswitch will not work if there is another driver using the GPU. If there is another driver using the GPU, you will get a warning inside journal. Simply remove the offending module by sudo rmmod nvidia or sudo rmmod nouveau.

  • If you want to boot with your GPU disabled, run:
echo options bbswitch load_state=0 unload_state=1 | sudo tee /etc/modprobe.d/bbswitch.conf

And blacklist any nvidia/nouveau driver that tries to load at boot, by editing /etc/modprobe.d/blacklist.conf:

blacklist nouveau
blacklist nvidia-drm
blacklist nvidia-modeset
blacklist nvidia-uvm
blacklist nvidia
  • If you did everything correctly, you should experience a significant drop in battery usage on idle (e.g., from 7W to 3.5W on idle), almost doubling your battery life.

CPU throttling issue

With the BIOS Version 1.52 (this problem is known to occur on 1.52, it might still happen on other versions too), the CPU tends to throttle down to 400 MHz earlier than it should. In particular, this can be seen when using Bumblebee.

After installing BIOS Version 1.54, this problem is fixed.

Speaker noise issue

The speaker on the Lenovo Thinkpad T490 may have a high static hissing noise, which does not change if you lower the volume, but stops if you mute the speaker or use the headphone jack. This problem cannot be fixed completely as of now. Updating to the most current BIOS version will make the speaker silent while it is not playing anything without you having to mute it all the time. But as soon as the user is playing sound, the noise will be back, clearly audible in the background.

Check the Lenovo Support Website for the newest BIOS Version.

Slow wakeup after suspend

After suspend the laptop takes a few second until it becomes responsive. Disallowing the access to the WWAN device in the BIOS solves this issue.

ACPI

The default /etc/acpi/handler.sh script has a check for the device that looks like this:

ac_adapter)
        case "$2" in
            AC|ACAD|ADP0)

This will not work, since the T490 device is called ACPI0003 which is not matched by the above check. The instructions in Acpid does mention a pattern that does work and it is recommended to use this instead.

Also See