Lenovo ThinkPad T440s

Compiler flags
See Safe CFLAGS.

USE flags
For the docking station you probably need the package with the   USE flag enabled.

Required packages

 * or for the Wi-Fi firmware
 * for the card reader

nVidia Optimus / Bumblebee support
This configuration allows for switching between integrated Intel GPU and nVidia GPU using primusrun (x11-misc/primus from bumblebee overlay).

Hardware and PCI slots

X.org server configuration

Bumblebee configuration

Secondary X server for nVidia

Trackpoint scrolling
With the new clickpad in the Thinkpad T440s, button events are now software based. This causes problems when using the classical combination of Xorg drivers: evdev for the trackpoint and synaptics for the touchpad. Since trackpoint scrolling (middle button + trackpoint movement) requires coordination between the two drivers, it does not work in the default configuration.

Working around the problem requires either
 * installing the patched xf86-input-evdev-trackpoint driver, available in the causalay overlay in layman and then configuring xorg by following this thread.
 * using the driver for both the trackpoint and the touchpad.

The second method is easier so it is described below.

libinput way
First add  to the   variable. As of the time of writing this (12:39, 25 July 2015 (UTC)) this flag is still masked due to the driver not being keyworded on all archs yet. To work around this, check that the driver has a keyword on your arch and override the mask in profile:

Then you can proceed to add the input device:

After the update the packages and  should've been pulled in.

Next you need to add the following Xorg configuration file so that the driver is selected for the devices we want.

After a reboot/xorg-server restart, trackpoint scrolling should work.