Thinkpad T480s

Martin Lautenbacher :toc: :icons: :numbered: :Revision: //:website: //:reproducible: //:source-highlighter: rouge //:source-highlighter: coderay //:listing-caption: Listing

Dualboot with Arch, Windows 10 and disk encryption

• Turn of secure boot in the BIOS.
• See link:dualboot.asciidoc[here].

Nvidia Optimus & Linux

• https://www.youtube.com/watch?v=5nGbWE-pvIE
• https://wiki.archlinux.org/index.php/PRIME
• https://wiki.archlinux.org/index.php/NVIDIA_Optimus
• https://wiki.archlinux.org/index.php/bumblebee

Bumblebee

1.  `pacman -Syu mesa xf86-video-intel nvidia bumblebee bbswitch`
2.  `sudo gpasswd -a user bumblebee` (replace _user_ with your
    username)
3.  `sudo systemctl enable bumblebeed.service`
4.  If tlp is installed and enabled:
    - Find the address of the GPU with `lspci | grep 3D` (First
      column, such as `01:00.0`)
    - Edit `/etc/default/tlp`:
+
    ...
    RUNTIME_PM_BLACKLIST="01:00.0"
    ...

5.  Configure bbswitch by editing: `/etc/modprobe.d/bbswitch.conf`
+
    options bbswitch load_state=0 unload_state=1

6.  Reboot


Usage/Testing
^^^^^^^^^^^^^

1.  To see if the dGPU is turned off/on: `cat /proc/acpi/bbswitch`
2.  To manually turn the dGPU on: `sudo tee /proc/acpi/bbswitch <<< ON`
3.  To manually turn the dGPU off: `sudo tee /proc/acpi/bbswitch <<< OFF`
4.  To unload nvidia modules manually: `sudo rmmod nvidia_uvm && sudo rmmod
    nvidia`
5.  To test if bumblebee is working correctly:
    - Check if dGPU is turned OFF
    - Run `optirun glxspheres64` or `optirun glxgears -info` (both in package
      `mesa-demos`)
    - While `glxgears` runs, check if dGPU is ON
    - Close the optirun terminal
    - Check if dGPU is OFF
    - For performance comparison, run `glxspheres64` or `glxgears` (without
      optirun)
6.  For improving performance, check https://wiki.archlinux.org/index.php/bumblebee#Optimizing_speed


.References
* http://lenovolinux.blogspot.com/2018/02/bumblebee-on-lenovo-t440p-nvidia-gt.html?m=1
* https://wiki.archlinux.org/index.php/Bumblebee


HiDPI & Linux
-------------

Adding this to my `~/.Xresources` has solved 90% of scaling for me (120 for 125% scaling):

.`~/.Xresources`
--------------------------
Xft.dpi: 120
Xft.autohint: 0
Xft.lcdfilter:  lcddefault
Xft.hintstyle:  hintfull
Xft.hinting: 1
Xft.antialias: 1
Xft.rgba: rgb

...
--------------------------

.References
* https://wiki.archlinux.org/index.php/HiDPI
* https://wiki.archlinux.org/index.php/Xorg#Display_size_and_DPI



CPU throttling fix
------------------

* Install `throttled` from the community repository.
* Configure `/etc/lenovo_fix.conf` with the desired undervolting etc.
* Start the service with `sudo systemctl enable --now lenovo_fix.service`
* **ATTENTION**: Choose your parameters carefully and do proper testing. Bad
  values may cause system instability, inability to boot or worse (possibly, I
  don't really know). Just be careful and change values incrementally with tests
  in between. Optimal values are individual to your machine.

.References
* https://www.reddit.com/r/thinkpad/comments/870u0a/t480s_linux_throttling_bug/
* https://wiki.archlinux.org/index.php/Lenovo_ThinkPad_X1_Carbon_(Gen_6)#Power_management.2FThrottling_issues
* https://github.com/erpalma/throttled


Power Management
----------------

* Packages:
  - `tlp`
  - `acpi_call`

.References
* http://thinkwiki.de/TLP_-_Linux_Stromsparen
* https://wiki.archlinux.org/index.php/TLP
* https://wiki.archlinux.org/index.php/Fan_speed_control
* https://wiki.archlinux.org/index.php/Undervolting_CPU
* https://wiki.archlinux.org/index.php/PHC
* https://wiki.archlinux.org/index.php/CPU_frequency_scaling
* https://wiki.archlinux.org/index.php/Laptop
* https://wiki.archlinux.org/index.php/Lenovo_ThinkPad_T480s
* https://wiki.archlinux.org/index.php/Lenovo_ThinkPad_T480


Other
-----

Special Buttons

Some buttons (Fn+F11, Fn+F12) have a keycode above 255 and are thus not supported by X. They can be remapped using:

ACPI Events ^^^^^^^^^^^

1. pacman -Syu acpid
2. sudo systemctl enable acpid.service
3. Modify /etc/acpi/handler.sh:

./etc/acpi/handler.sh [source,Bash]

...

ibm/hotkey)
  case "$4" in
      00001311)
          logger 'Favorites'
          /etc/acpi/actions/favorites-key.sh
          ;;
      00001315)
          logger 'Keyboard'
          /etc/acpi/actions/keyboard-key.sh
          ;;
      *)
          logger "ACPI action undefined: $1 : $2 : $3 : $4"
          ;;

esac ;;

...

---

.References

• https://wiki.archlinux.org/index.php/acpid

udev hwdb ^^^^^^^^^

1. Modify /etc/udev/hwdb.d/90-thinkpad-keyboard.hwdb:

./etc/udev/hwdb.d/90-thinkpad-keyboard.hwdb

evdev:name:ThinkPad Extra Buttons:dmi:bvn*:bvr*:bd*:svnLENOVO*:pn* KEYBOARD_KEY_45=prog1 KEYBOARD_KEY_49=prog2

---

2. sudo udevadm hwdb --update
3. sudo udevadm trigger --sysname-match="event*"

.References

• https://wiki.archlinux.org/index.php/Lenovo_ThinkPad_T480#Special_buttons
• https://wiki.archlinux.org/index.php/Map_scancodes_to_keycodes