Hackery

ThinkPad X250 on CentOS 7

Tue 06 Oct 2015

Wow, almost a year since the last post. Definitely time to reboot the blog.

Got to replace my aging ThinkPad X201 with a lovely shiny new ThinkPad X250 over the weekend. Specs are:

CPU: Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
RAM: 16GB PC3-12800 DDR3L SDRAM 1600MHz SODIMM
Disk: 256GB SSD (swapped out for existing Samsung SSD)
Display: 12.5" 1920x1080 IPS display, 400nit, non-touch
Graphics: Intel Graphics 5500
Wireless: Intel 7265 AC/B/G/N Dual Band Wireless and Bluetooth 4.0
Batteries: 1 3-cell internal, 1 6-cell hot-swappable

A very nice piece of kit!

Just wanted to document what works and what doesn't (so far) on my standard OS, CentOS 7, with RH kernel 3.10.0-229.11.1. I had to install the following additional packages:

iwl7265-firmware (for wireless support)
acpid (for the media buttons)

Working so far:

media buttons (Fn + F1/mute, F2/softer, F3/louder - see below for configuration)
wifi button (Fn + F8 - worked out of the box)
keyboard backlight (Fn + space, out of the box)
sleep/resume (out of the box)
touchpad hard buttons (see below)
touchpad soft buttons (out of the box)

Not working / unconfigured so far:

brightness buttons (Fn + F5/F6)
fingerprint reader (supposedly works with fprintd)

Not working / no ACPI codes:

mute microphone button (Fn + F4)
application buttons (Fn + F9-F12)

Uncertain/not tested yet:

switch video mode (Fn + F7)

To get the touchpad working I needed to use the "evdev" driver rather than the "Synaptics" one - I added the following as /etc/X11/xorg.conf.d/90-evdev.conf:

Section "InputClass"
  Identifier "Touchpad/TrackPoint"
  MatchProduct "PS/2 Synaptics TouchPad"
  MatchDriver "evdev"
  Option "EmulateWheel" "1"
  Option "EmulateWheelButton" "2"
  Option "Emulate3Buttons" "0"
  Option "XAxisMapping" "6 7"
  Option "YAxisMapping" "4 5"
EndSection

This gives me 3 working hard buttons above the touchpad, including middle-mouse- button for paste.

To get fonts scaling properly I needed to add a monitor section as /etc/X11/xorg.conf.d/50-monitor.conf, specifically for the DisplaySize:

Section "Monitor"
  Identifier    "Monitor0"
  VendorName    "Lenovo ThinkPad"
  ModelName     "X250"
  DisplaySize   276 155
  Option        "DPMS"
EndSection

and also set the dpi properly in my ~/.Xdefaults:

*.dpi: 177

This fixes font size nicely in Firefox/Chrome and terminals for me.

I also found my mouse movement was too slow, which I fixed with:

xinput set-prop 11 "Device Accel Constant Deceleration" 0.7

(which I put in my old-school ~/.xsession file).

Finally, getting the media keys involved installing acpid and setting up the appropriate magic in 3 files in /etc/acpid/events:

# /etc/acpi/events/volumedown
event=button/volumedown
action=/etc/acpi/actions/volume.sh down

# /etc/acpi/events/volumeup
event=button/volumeup
action=/etc/acpi/actions/volume.sh up

# /etc/acpi/events/volumemute
event=button/mute
action=/etc/acpi/actions/volume.sh mute

Those files capture the ACPI events and handle them via a custom script in /etc/acpi/actions/volume.sh, which uses amixer from alsa-utils. Volume control worked just fine, but muting was a real pain to get working correctly due to what seems like a bug in amixer - amixer -c1 sset Master playback toggle doesn't toggle correctly - it mutes fine, but then doesn't unmute all the channels it mutes!

I worked around it by figuring out the specific channels that sset Master was muting, and then handling them individually, but it's definitely not as clean:

#!/bin/sh
#
# /etc/acpi/actions/volume.sh (must be executable)
#

PATH=/usr/bin

die() {
  echo $*
  exit 1
}
usage() {
  die "usage: $(basename $0) up|down|mute"
}

test -n "$1" || usage

ACTION=$1
shift

case $ACTION in
  up)
    amixer -q -c1 -M sset Master 5%+ unmute
    ;;
  down)
    amixer -q -c1 -M sset Master 5%- unmute
    ;;
  mute)
    # Ideally the next command should work, but it doesn't unmute correctly
#   amixer -q -c1 sset Master playback toggle

    # Manual version for ThinkPad X250 channels
    # If adapting for another machine, 'amixer -C$DEV contents' is your friend (NOT 'scontents'!)
    SOUND_IS_OFF=$(amixer -c1 cget iface=MIXER,name='Master Playback Switch' | grep 'values=off')
    if [ -n "$SOUND_IS_OFF" ]; then
      amixer -q -c1 cset iface=MIXER,name='Master Playback Switch'    on
      amixer -q -c1 cset iface=MIXER,name='Headphone Playback Switch' on
      amixer -q -c1 cset iface=MIXER,name='Speaker Playback Switch'   on
    else
      amixer -q -c1 cset iface=MIXER,name='Master Playback Switch'    off
      amixer -q -c1 cset iface=MIXER,name='Headphone Playback Switch' off
      amixer -q -c1 cset iface=MIXER,name='Speaker Playback Switch'   off
    fi
    ;;
  *)
    usage
    ;;
esac

So in short, really pleased with the X250 so far - the screen is lovely, battery life seems great, I'm enjoying the keyboard, and most things have Just Worked or have been pretty easily configurable with CentOS. Happy camper!

References: