Thinkpad twist

Thinkpad Twist (s230u)

Using a standard stage3 installation everything should pretty much work out of the box.

Keyboard

for some reason on kernels >= 4.2 the keyboard, trackpoint and touchpad are not working on the first boot. To work around this problem add i8042.nomux=1 i8042.reset to your kernel command line:

FILE /etc/default.grubadd to kernel command line

GRUB_CMDLINE_LINUX_DEFAULT="i8042.nomux=1 i8042.reset"

WiFi

the wifi chip is a Intel Wireless-N 2230 as lspci shows

03:00.0 Network controller: Intel Corporation Centrino Wireless-N 2230 (rev c4)

enable the required kernel modules:

KERNEL

Device Drivers  --->
  [*] Network device support  --->
    [*]   Wireless LAN  --->
      [ ]   ADMtek devices
      [ ]   Atheros/Qualcomm devices
      [ ]   Atmel devices
      [ ]   Broadcom devices
      [ ]   Cisco devices
      [*]   Intel devices
      < >     Intel PRO/Wireless 2100 Network Connection
      < >     Intel PRO/Wireless 2200BG and 2915ABG Network Connection
      < >     Intel Wireless WiFi 4965AGN (iwl4965)
      < >     Intel PRO/Wireless 3945ABG/BG Network Connection (iwl3945)
      <M/*>   Intel Wireless WiFi Next Gen AGN - Wireless-N/Advanced-N/Ultimate-N (iwlwifi)
      <M/*>   Intel Wireless WiFi DVM Firmware support
      < >     Intel Wireless WiFi MVM Firmware support

the modules need an additional firmware

root #emerge --ask sys-kernel/linux-firmware

if you are building the modules directly into the kernel enable the Include in-kernel firmware blobs in kernel binary option

KERNEL

Device Drivers  --->
  Generic Driver Options  --->
    -*- Userspace firmware loading support
    [*]   Include in-kernel firmware blobs in kernel binary
    (iwlwifi-2030-6.ucode) External firmware blobs to build into the kernel binary
    (/lib/firmware) Firmware blobs root directory
    [ ] Fallback user-helper invocation for firmware

see When using built in configuration

Audio / Video

The sound card work out of the box for USB mic/soundcard enable:

KERNEL

Device Drivers  ---> 
      <*> Sound card support  ---> 
          <*>   Advanced Linux Sound Architecture  ---> 
              [*]   USB sound devices  ---> 
                  <M>   USB Audio/MIDI driver

The integrated webcam is also USB:

KERNEL

Device Drivers --->
    <M> Multimedia support --->
      [*] Media USB Adapters --->
        [M] USB Video Class (UVC)

Card Reader

the card reader is an RTS5229 PCI Express Card Reader - the driver comes with a package rather than with the kernel itself so make sure to deselect:

KERNEL

Device Drivers --->
    Misc devices--->
      < > Realtek PCI-E card reader

and emerge

root #emerge --ask sys-block/rts5229

don't forget to re-emerge when installing a new kernel

Note
It was mentioned in the discussions that the driver package may not be necessary if both "Realtek PCI-E card reader" (CONFIG_MISC_RTSX_PCI) and "Realtek PCI-E SD/MMC Card Interface Driver" (CONFIG_MMC_REALTEK_PCI) are enabled in the kernel.