Linux on a Lenovo Thinkpad X240

This isn't really a page on installing any particular flavour of Linux on a Thinkpad X240 but rather a collection of hacks I've aggregated while making the machine work like I want it to. I generally run Debian stable on my machines, so some the things may need adaptation for other distributions.

Not all of this is specific to the X240, and quite a bit not even to Thinkpads.

In case you came here looking for advice whether to get such a machine: Well, this isn't a review, but I like the fact that the machine runs on something like 4 Watts in indoor lighting and hence it's entirely realistic to do about 20 hours of normal work from a single charge. I don't like the silly, button-less touch pad, the Win8-style "function key-with-modifier" scheme and the general lack of LEDs.

Kernel and such

I traditionally compile my own kernels. Call me weird, but I actually like not having to worry about initrds. On the other hand, this requires some research into what drivers are needed for the hardware. To save you time if you're similarly inclined, here's my kernel .config as of the compile time of this page.

Here's some of the main hardware driver modules in use on my system:

Fixing major annoyances

Function Keys

The way the machine is delivered, when you hit a function key you get some silly special function (volume, brightness, toggle camera, etc). I cannot begin to grasp who might come up with crap like this. Fortunately, FnLock (hit Fn+ESC) is persistent over reboots, so hit it and more or less forget it.

An annoyance remains, though: Instead of the useful End key you get the useless Insert key with FnLock. To fix this, dump this into /lib/udev/hwdb.d/61-ThinkPad-X240-keyboard.hwdb:

# ThinkPad X240: switch End and Insert keys (so that when Fn-Lock is enabled, End works without Fn).
keyboard:dmi:bvn*:bvr*:bd*:svnLENOVO:pn*:pvrThinkPadX240:*
	KEYBOARD_KEY_d2=end
	KEYBOARD_KEY_cf=insert

File: /lib/udev/hwdb.d/61-ThinkPad-X240-keyboard.hwdb

You'll have to run udevadm hwdb --update after that. (This hack courtesy of Thinkwiki x240).

Touchpad

The single most stupid design flaw of the X240 is that it doesn't have hardware mouse keys. I have been unable to use the touchpad as a replacement while it was still configured to move the mouse pointer. In the end, I'm using some configuration that kills all movement from the touchpad (use the trackpoint) and more or less equally distribute the area between the three mouse buttons. There is additional configuration in case I want to recover pad movement later. To use this, drop this into /etc/X11/xorg.conf.d/50-synaptics.conf:

Section "InputClass"
	Identifier "touchpad"
	MatchProduct "SynPS/2 Synaptics TouchPad"
	Driver "synaptics"
	Option "PalmDetect" "True"
	Option "ClickPad" "True"
	Option "SoftButtonAreas" "67% 100% 0 0 30% 67% 0 0"
	# Ganz aus: BottomEdge 10 TopEdge 0
	Option "AreaTopEdge" "0"
	Option "AreaBottomEdge" "1"
	Option "CircularScrolling" "False"
	Option "CircScrollingDelta" "0"
	Option "VertResolution" "1000"
	Option "HorizResolution" "650"
	Option "MinSpeed" "1"
	Option "MaxSpeed" "1"
	Option "AccelerationProfile" "1"
	Option "AdaptiveDecelration" "16"
	Option "ConstantDecelration" "16"
	Option "VelocityScale" "1"
	Option "HasSecondarySoftButtons" "False"
EndSection

File: /etc/X11/xorg.conf.d/50-synaptics.conf

LEDs

Call me conservative, but I like some blinking when the machine is doing something. For Wifi the useless FnLock LED (that's otherwise continually on) can be made useful by connecting its trigger with the WiFi's transmit activity by dropping the following into /etc/network/if-up.d/ledblink:

#!/bin/sh
case $IFACE in
eth*|wlan*)
	LED_NAME="tpacpi::unknown_led"
	TRIGGER="/sys/class/leds/$LED_NAME/trigger"
	if grep "phy[0-9]*tx" "$TRIGGER" > /dev/null; then
		TX_NAME=`sed -e 's/.*\(phy[0-9]*tx\).*/\1/' "$TRIGGER"`
		echo $TX_NAME > $TRIGGER 
	fi
;;
esac

File: /etc/network/if-up.d/ledblink

I also believe disk access should not go unnoticed, and so I let the power LED blink when there's some traffic on the SATA bus. This needs to be re-configured after every suspend/resume cycle, and so this sits in the pmutils configuration:

#!/bin/sh
case "$1" in
	resume|thaw)
		echo ide-disk > "/sys/class/leds/tpacpi::power/trigger"
		:
	;;
esac
exit 0

File: /etc/pm/sleep.d/70diskled

If you reboot now and then, you might want to add the echo into your rc.local, too.

Incidentally, with the above kernel config (which allows fiddling with "important" LEDs, here's what other LEDs I've found:

The other stuff in /sys/class/leds doesn't seem to be connected on the x240. There's a beautiful red light below the mute button that'd really like to control, too, and blue operation LED of the camera would be nifty, too (though I suspect both might not be available for programmatic control for "security" reasons; sigh).

The red LED below the microphone mute key at least is available for ACPI control. With acpi_call (which you want anyway), you can switch it on or let it blink with:

echo '\_SB.PCI0.LPC.EC.LED 0x0e 0x80' | sudo tee /proc/acpi/call
echo '\_SB.PCI0.LPC.EC.LED 0x0e 0xc0' | sudo tee /proc/acpi/call
echo '\_SB.PCI0.LPC.EC.LED 0x0e 0x00' | sudo tee /proc/acpi/call

While I was reading docs on the LED subsystem, it occurred to me that something like an "you're about to forget undoing something" indicator would be great for me. I my case, that's mounting something, in particular some encrypted container, using my little "with" utility, where I should not forget to exit the shells started by it. I figured a blinking power LED might be just the thing I need there without actually keeping the machine from actually suspending when I don't care. So, I came up with this script that's now called with enter and exit as parameters in with:

#!/bin/sh
# On a thinkpad, make the power button do a heartbeat (or turn it off again)
# Since you need appropriate privileges to change LEDs, this tries to
# sudo itself.  To really enjoy this, you'll want something like
# NOPASSWD: /usr/local/bin/mark-critical in your user's sudoers line.

LEDDIR="/sys/class/leds/tpacpi::power"

if [ "t$2" == treally ]; then
	setled() {
		redled $1 || echo heartbeat > "$LEDDIR/trigger"
	}
else
	setled() {
		echo $1 > "$LEDDIR/trigger"
	}
fi

modprobe ledtrig_heartbeat

if id | grep root 2>&1 > /dev/null
then
	:
else
	exec sudo $0 $*
fi

case $1 in
	enter)
		setled heartbeat
		;;
	exit)
		setled none
		;;
	*)
		echo "Usage: $0 enter|exit"
		;;
esac

File: /usr/local/bin/mark-critical

Battery and Power

Since I happen to adhere to the religion that it's charge-discharge cycles in general and in particular deep charge-discharge cycles that wear out rechargables, I totally ignore the recommendation from Lenovo's docs to completely discharge the battery before recharging it. Frankly, I think it's utter bullshit.

Instead, when there's no reason to expect I'll actually need 20 hours of juice, I usually limit charging to 80% of full. To do this, you need two ingredients: A kernel module called acpi_call, and, for convenience, the tpacpi-bat script. For even more convenience, I'm using the following shell script to configure the system to charge as much as possible ("travel") to charge below 70% up to 80% ("normal") or to not charge at all ("nocharge"; this is useful if you have weakish power supplies and want to run the machine from them):

#!/bin/sh
if id | grep root 2>&1 > /dev/null
then
	true
else
	exec sudo $0 $*
fi

usage() {
	echo "Usage: $0 [show|travel|normal|nocharge]"
	exit 1
}

case "$1" in
show)
	echo "Start/Stop 1:" `tpacpi-bat -g ST 1` `tpacpi-bat -g SP 1`
	echo "Start/Stop 2:" `tpacpi-bat -g ST 2` `tpacpi-bat -g SP 2`
	;;
travel)
	tpacpi-bat -s --start 0 0
	tpacpi-bat -s --stop 0 0
	;;
normal)
	tpacpi-bat -s --start 0 67
	tpacpi-bat -s --stop 0 74
	;;
nocharge)
	tpacpi-bat -s --start 0 1
	tpacpi-bat -s --stop 0 1
	;;
*)
	usage
	;;
esac

File: /home/msdemlei/mybin/chargeconfig

As the battery's estimate of its current capacity decreases, I'm decreasing the threshold, too, as it apparently is the threshold of the design capacity; on a new rechargable, you'll probably want to re-set them to 60/80.

The whole machine can run on something like 3.5 watts running an editor and dim-environment backlight, but it's important to control the video chip to make that happen. With my setup, the i915 driver is loaded as a module and the parameters can be passed in through modprobe. I don't keep this separate but instead in my local modprobe configuration together with several blacklists that may or may not be appropirate for your setup:

options i915 enable_rc6=7 enable_fbc=1 enable_dc=2
options iwlwifi power_save=1 power_level=3 bt_coex_active=1 11n_disable=1 
#options iwlwifi power_save=1 power_level=3

options snd-hda-intel patch=x240-alsa.fw,x240-alsa.fw,x240-alsa.fw

blacklist e1000e
blacklist sierra_net
blacklist cdc_mbim
blacklist cdc_ncm
blacklist bluetooth
blacklist btintel
blacklist btusb

File: /etc/modprobe.d/local.conf

On the weird snd_hda_intel line see below

As some of my bright or less bright settings for power saving get clobbered during suspend/resume (and possibly even by laptop-mode), I'm currently doing a fairly ugly hack pending a closer examination of what's going on; it's a good place to put hacks in, so I'll tell you what I do anyway. First, I'm telling pm-suspend and friends to execute some of my code roughly a minute after waking up (to reduce the likelihood of interfering with laptop-mode's wakeup procedures):

#!/bin/sh
# This sets some extra power saving stuff after laptop-mode and
# friends have done their job -- it's stuff they sometimes mess
# up.
case "$1" in
	thaw|resume)
		echo "/usr/local/sbin/extrapower.sh" | at -M "now+1 min"
		;;
	suspend|hibernate)
		echo 0 > /sys/class/leds/tpacpi\:\:power/brightness
		;;
esac
exit 0

File: /etc/pm/sleep.d/20morepower

The script referenced there currently is a bit of an experimental hodgepodge

#!/bin/sh
# A temporary hack to enable some extra power management after wakeup.
# This is run after the built-in machinery as some of this
# is destroyed by who-knows-what.
# This is executed from within /etc/pm/sleep.d/20morepower

echo '1500' > /proc/sys/vm/dirty_writeback_centisecs
echo 'auto' > /sys/bus/usb/devices/1-4/power/control
echo 'auto' > /sys/bus/usb/devices/2-4/power/control
echo 5 > /sys/module/iwlwifi/parameters/power_level
rfkill block bluetooth

File: /usr/local/sbin/extrapower.sh

With this configuration, powertop reports up to 75% in PC7 (i.e., the whole processor package is in deep sleep) on an unloaded system.

Monitoring

Just as my trusty old XP731, the X240 has two batteries, and it still seems that's not terribly well supported by most of the battery applets. So, I continued to hack on my little window make dockapp (that works just dandy in most other places), which is a fork from wmacpimon. Prod me to do a proper release one of theses days; meanwhile, get the stuff from SVN or as a tarball.

Screen Brightness

The backlight eats up a significant percentage of the power of the system, so keeping it down to whatever the environment allows really helps battery life. Doing it manually is, of course, not an option, so I've written a little piece of opencv-based python (dependency: python-opencv): adjust_backlight.py. You may want to adjust the levels in THRESHOLDS to your taste – I suspect you'll find my levels a bit too low, in particular in brighter light.

In practice, I'm executing this after system wakeup, because quite typically lighting conditions don't change much unless I move (and hence let the machine sleep). This, in turn, is started from a shell script that I let pm-suspend run under my unprivileged user-id. To make that happen, I dump a little shell script into /etc/pm/sleep.d:

#!/bin/sh
case "$1" in
	resume|thaw)
		su msdemlei -c "~/mybin/afterwakeup"
		;;
esac
exit 0

File: /etc/pm/sleep.d/40userscript

Of course, you'll have to adjust msdemlei to your user id, and this assumes your user script is called mybin/afterwakeup. In case you're curious or are looking for inspriation what to put into such a wakeup script, here's mine (hoping I won't acidentally put something confidential in there:):

#!/bin/sh
cd
killall dclock
export DISPLAY=:0 
if [ -f ~/.afterwakeup ]; then
	LC_ALL=de_DE.UTF-8 /usr/games/xcowsay `cat ~/.afterwakeup` &
else
	LC_ALL=de_DE.UTF-8 /usr/games/xcowfortune&
fi

dclock&
xplanet -tmpdir ~/.xplanet/images -config overlay_clouds -projection rectangular -num_times 1&
(sleep 1; python ~/mybin/adjust_backlight.py)&
(sleep 6; ~/mybin/display-phone-status.sh)&
(sleep 10; sudo rfkill block bluetooth)&
~/mybin/ifdocked &

File: /home/msdemlei/mybin/afterwakeup

Sound

I run alsa natively, i.e., without pulse or any similar cruft in between. Unfortunately, the X240's sound hardware is a bit sucky in that:

To solve all this, I'm using a special /etc/asound.conf:

pcm.!default {
	type plug
	slave.pcm {
		@func getenv
			vars [ ALSA_SLAVE ]
			default share
		}
}

pcm.share {
	type plug
	slave {
		pcm boosted
	}
}

pcm.boosted {
	type softvol
	slave {
		pcm mixed
	}
	control {
		name "Playback Boost"
		card 1
	}
	min_dB -15.0
	max_dB 15.0
}

pcm.mixed {
	type dmix
	ipc_key 1024
	ipc_key_add_uid false
	ipc_perm 0666
	slave spkr
	bindings {
		0 0
		1 1
	}
}

pcm_slave.spkr {
	pcm "hw:1,0"
	period_time 0
	period_size 735
	buffer_size 11025
	channels 2
	rate 44100
	format S16_LE
}

ctl.!default {
	type hw
	card 1
}

pcm.glotze {
	type hw
	card 0
	device 3
}

File: /etc/asound.conf

This does the sample rate adaption (via the plughw slave), puts the HDMI control in the background and allows for some pre-amplification for sources that have a bit of extra dynamic range. To quickly switch between pre-amping and not (to avoid overmodulation), I've also added

(bind-keys global-keymap "M-F1" '(system "amixer set 'Playback Boost' 128"))
(bind-keys global-keymap "S-M-F1" '(system "amixer set 'Playback Boost' 256"))

to my .sawfishrc (note the icon on F1...).

There's an extra issue when you have a dock; at least for the Ultradock and with recent kernels up to 4.5, the audio jack (or headphone jack, if you want) will be mute, and there's no mixer control to fix this.

Fixing this is pure voodo; in case you want to understand a bit of what's going on, peruse Documentation/sound/hd-audio/notes.rst (the "Early Patching" chapter). If not, to get sound out of the ultradock's audio jack, you'll need to do two things:

  1. Drop a this into /lib/firmware/x240.alsa.fw:
    [codec]
    0x10ec0292 0x17aa2214 0
    
    [pincfg]
    0x16 0x21211010
    0x19 0x21a11010
    

    File: /lib/firmware/x240-alsa.fw

  2. Arrange for this "patch" to be loaded. For that, you need a line like options snd-hda-intel patch=x240-alsa.fw,x240-alsa.fw,x240-alsa.fw in somewhere in modprobe.d. The above modprobe.d/local.conf already contains this. The "firmware" file name is given three times since at least kernel 4.5 recognises three different hardware outputs (try aplay -L | grep "^hw:").

In case this doesn't help (after reloading the snd-hda-intel), make sure your kernel is compiled with CONFIG_SND_HDA_PATCH_LOADER.

Phone hardware

Somewhat to my surprise my X240 had an LTE modem built in. I still got myself a SIM card, but just so the carrier doesn't necessarily know where I am and when I switch my computer on and off, the first thing I tried was figure out how to keep it from registering with the network. It turns out that's a bit tricky across wakeups, and so I ended up using rfkill. You'll need the thinkpad_acpi module, after which you should see something like

$ rfkill list
0: tpacpi_bluetooth_sw: Bluetooth
	Soft blocked: no
	Hard blocked: no
1: tpacpi_wwan_sw: Wireless WAN
	Soft blocked: no
	Hard blocked: no
172: phy170: Wireless LAN
	Soft blocked: no
	Hard blocked: no

The high number on the wifi is because I keep removing the module when the thing is not in use. To be independent of the enumeration of the blocks, you can use rfkill's symbolic names to define two aliases:

alias fon="sudo rfkill unblock wwan"
alias keinfon="sudo rfkill block wwan"

together with accompanying entries in sudoers (like user NOPASSWD:/usr/sbin/rfkill).

In case you're curious, I use common ifupdown to manage this; currently, I'm still going through pppd, where /etc/network/interfaces has

iface o2 inet ppp
  provider o2

This refers to a file in /etc/ppp/peers that probably would work pretty much like this for you, too:

/dev/ttyACM0
115200
debug
noauth
usepeerdns
ipcp-accept-remote
ipcp-accept-local
remotename any
user thing
local
nocrtscts
defaultroute
noipdefault
connect "/usr/sbin/chat -v -f /etc/ppp/chat-o2"

which in turn uses /etc/ppp/chat-o2; unless you happen to use their infrastructure, you'll need to fix the APN; you may need further authentication, but these days I suspect you don't.

TIMEOUT 5
ECHO ON
ABORT 'BUSY'
ABORT 'ERROR'
ABORT 'NO ANSWER'
ABORT 'NO CARRIER'
ABORT 'NO DIALTONE'
ABORT 'RINGING\r\n\r\nRINGING'
TIMEOUT 12
'' "ATZ"
OK 'ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0'
OK 'AT+CGDCONT=1, "IP", "pinternet.interkom.de"'
OK "\d\dATD*99#"
CONNECT ""

File: /etc/ppp/chat-o2

I plan to move all this to mbim at some point, but as the PPP hack works ok, there's not terribly much incentive. If you send me recipes, I'll certainly study them, though.

The modem (it's a Sierra EM7354, USB-id 1199:a001) sometimes (and I've not figured out why) switches itself to some other mode ("cfun"). Also, it turns out that it's advantageous to control the access technology (GSM, UMTS, LTE) manually, as sometimes some of them are unavailable or temporarily broken, and autoselection doesn't appear to work particularly well.

To solve both problems (and help figure out what the modem thinks it's doing), I wrote modemconfig.py. Try modemconfig.py --help to figure out how to use it. It doesn't need to run as root if you add yourself to the dialout group.

Power Connector

Ok, this has nothing to do with Linux, but in all likelihood you have 19 V power supplies that you might want to re-use with your X240. Well, trouble is, the power connector is some proprietary crap roughly in USB format with a single pin in the center. You can get adapters from eBay and various places (keywords like "thinkpad power charger cable adapter"; the X1 carbon has the same thing).

The adapters I had stank, in particular because with the plug and the connector you have several centimeters of mess sticking out of your machine while charging. I hence took my Dremel and cut off most of the junk. If you want to do the same thing, here's how the connector on the thinkpad side needs to be wired:

	____________________________
	|                          | 3
	|1           o 2          1|
	|__________________________|

On the inside of the plug (1), there is roughly +19 V (note that when running and charging, the X240 may pull quite a bit of juice; the power adapters for the 2.5 Amp XP731 sometimes shut down due to overload; then again, I've not tried putting in a smaller resistor yet). The pin in the center (2) is pulled down to ground with a resistor that encodes the output of the power supply. There's a table of known values over on the ThinkpadWiki's power connector page. Finally, the outside of the plug (3) is ground.

Here's some photos of my conversion of an adapter to a usable plug that doesn't add 10 cm to the width of the machine (the images' titles contain a bit of explanation):

Looks awful (though perhaps not quite as awful once you take away excess cork and smooth the whole thing a bit, but the three plugs I made have survived quite a bit of travel and other abuse in the past two years.


Last update: 2020-07-06, 20:07 UTC.

Markus Demleitner