Touchpad Synaptics

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Introduction

synaptics is a driver for the Synaptics TouchPad which is manufactured in most laptops. This article will help install and configure the driver according to your needs.

Installation

You can install the synaptics modules via pacman from the extra repository:

# pacman -S synaptics

Edit /etc/X11/xorg.conf as root and add InputDevice "Touchpad" "AlwaysCore" to the ServerLayout:

Section "ServerLayout"
	...
	InputDevice    "USB Mouse" "CorePointer"
	InputDevice    "Touchpad"  "AlwaysCore"
EndSection

Add Load "synaptics" to the Module section, for example:

Section "Module"
	...
	Load  "freetype"
	Load  "record"
	Load "synaptics"
	...
EndSection

Lastly, add a new InputDevice section for the touchpad itself:

Section "InputDevice"
	Identifier      "Touchpad"
       Driver          "synaptics"
       Option  "Device"        "/dev/input/mouse0"
	Option  "Protocol"      "auto-dev"
	Option  "LeftEdge"      "1700"
	Option  "RightEdge"     "5300"
	Option  "TopEdge"       "1700"
	Option  "BottomEdge"    "4200"
	Option  "FingerLow"     "25"
	Option  "FingerHigh"    "30"
	Option  "MaxTapTime"    "180"
	Option  "MaxTapMove"    "220"
	Option  "VertScrollDelta" "100"
	Option  "MinSpeed"      "0.06"
	Option  "MaxSpeed"      "0.12"
	Option  "AccelFactor" "0.0010"
	Option  "SHMConfig"     "on"
EndSection

Save, exit and restart X. The touchpad should now have working scroll zones. You can further tweak the InputDevice settings if desired. See Advanced Configuration for more information.

Note that your newly modified Xorg config will automatically load the evdev and psmouse kernel modules required by synaptics, however if desired you may add them explicitly to the MODULES array in the /etc/rc.conf file:

MODULES=( ... evdev psmouse ... )

Configurations using GUI applications

Gsynaptics

Once the synaptics driver has been installed, GNOME users can also install the gsynaptics package to enable a GUI-based control panel:

# pacman -S gsynaptics

To save and load the settings from gsynaptics automatically, add gsynaptics-init to the list of Startup Programs found in System -> Preferences -> Sessions.

Note: Non-GNOME users can also use gsynaptics by instead adding gsynaptics-init to their .xinitrc or .xsession startup scripts.

Advanced Configuration

The synaptics driver offers a number of options that can be customized. The following list describes the InputDevice options we declared in the Xorg config:

Identifier is the name of this input device you've specified in the server layout section above.

Device defines where your synaptic device is located. See Troubleshooting to find your device handler if it isn't /dev/input/mouse0 for you.

LeftEdge, RightEdge, TopEdge and BottomEdge are integer values which indicate the dimensions of your touchpad as x or y coordinates.

FingerLow and FingerHigh are integer value which indicate the 'pressure value' at which the driver counts a touch (pressure value goes above FingerHigh) or a release (pressure value drops below FingerLow).

MaxTapTime is an integer value that defines the maximum time for detecting a tap (in milliseconds).

MaxTapMove is an integer value which defines the maximum movement of your finger for detecting a tap.

MinSpeed and MaxSpeed are set to determine the minimum and maximum speed factor. An floating point value is expected.

AccelFactor is the acceleration factor as well defined as a floating point value.

SHMConfig is a boolean value (on/off) for activating or deactivating shared memory. This needs to be enabled if you want to monitor or configure your synaptics device with clients as synclient, which will be using in this article.

More options are explained in the synaptics' manpage, accessible with:

man 5 synaptics

Fine tuning with synclient

The synclient monitor can display pressure and placement on the touchpad in real-time, allowing further refinement of the default synaptics settings. In order for synclient to work properly, the SHMConfig option must be set to on or true.

You can start the synaptics monitor with the following command:

$ synclient -m 100

Where -m activates the monitor and the following number specifies the update interval in milliseconds.

This monitor provides information about the current state of your touchpad. For example, if you move the mouse with the touchpad, the x and y values in the monitor will change. Therewith you can easy figure out your touchpad's dimension which is defined in the LeftEdge-, RightEdge-, BottomEdge- and TopEdge-Options.

The abbreviations are explained as following:

time

Time in seconds since the logging was started.

x, y

The x/y coordinates of the finger on the touchpad. The origin is in the upper left corner.

z

The pressure value. It represents the pressure you are using to navigate on your thouchpad.

f

Number of fingers currently touching the touchpad.

w

Value that represents the finger width.

l,r,u,d,m,multi

Those values represent the state of the left, right, up, down, middle and multi buttons pressed where zero means not pressed and one means pressed.

gl,gm,gr

For touchpads which have a guest device, this are the associated button states for guest left, guest middle and guest right pressed (1) and not pressed (0).

gdx, gdy

x/y coordinates of the guest device.

If a value constantly is zero, it means that this option is not supported by your device.

With this in mind you should be able to figure the proper values out for you.

Circular scrolling

Circular scrolling is a feature that synaptics offers which you probably know from the iPod. Instead of (or additional to) scrolling horizontally or vertically, you can scroll circularly. Some users find this faster and more precise. To enable circular scrolling, you have to add the following options to your input device section as defined above:

Section "InputDevice"
        ...
        Option      "CircularScrolling"          "on"
        Option      "CircScrollTrigger"          "0"
        ...
EndSection

As you've might guessed CircularScrolling enables or disables circular scrolling. The option CircScrollTrigger may be one of the following values, determining on which edge circular scrolling should start:

0    All Edges
1    Top Edge
2    Top Right Corner
3    Right Edge
4    Bottom Right Corner
5    Bottom Edge
6    Bottom Left Corner
7    Left Edge
8    Top Left Corner

Specifying something different from zero may be useful if you want to use circular scrolling in conjunction with horizontal and / or vertical scrolling. If you do so, the type of scrolling is determined by the edge you're starting.

To scroll fast, draw small circles in the center of your touchpad. To scroll slow and more precise, draw large circles.

Disabling touchpad on plugged in mouse

In assistance to udev, it is possible to automatically disable the touchpad if an external mouse has been plugged in.

To achieve this, you just have to add the following udev rule:

ACTION=="add", SUBSYSTEM=="input", ID_CLASS="mouse", RUN+="/usr/bin/synclient TouchpadOff=1"
ACTION=="remove", SUBSYSTEM=="input", ID_CLASS="mouse", RUN+="/usr/bin/synclient TouchpadOff=0"

Place this into /etc/udev/rules.d/01-touchpad.rules and make sure SharedMemory has been enabled and you should be fine.

Troubleshooting

My touchpad device isn't located at /dev/input/mouse0

If that's the case, you can use this command to display information about your all input devices:

cat /proc/bus/input/devices

Search for an input device which has the name "SynPS/2 Synaptics TouchPad". The Handler in this section will tell you which Device you have to specify in your xorg.conf.

Example output:

I: Bus=0011 Vendor=0002 Product=0007 Version=0000
N: Name="SynPS/2 Synaptics TouchPad"
P: Phys=isa0060/serio4/input0
S: Sysfs=/class/input/input1
H: Handlers=mouse0 event1 
B: EV=b
B: KEY=6420 0 7000f 0

As your Handlers are mouse0 and event1, you use /dev/input/mouse0.

Stopping the mouse from clicking while typing

This is a neat little trick incorporated with the synaptics driver, you can actually make sure that the touchpad is disabled while typing. It is a very simple procedure, so here is how it is done.

Just add the following line to your .xinitrc before you run your window manager:

syndaemon -i 2 &

The -i 2 switch sets the idle time to 2 seconds. The idle time specifies how many seconds to wait after the last key press before enabling the touchpad again.

Additionally you can add the -t switch that tells the daemon not to disable mouse movement when typing and only disable tapping and scrolling:

syndaemon -t -i 2 &

As usual you may find further information in the manpage:

$ man syndaemon

Firefox misinterprets horizontal scrolling

Even though this problem isn't concerning the synaptics drivers, you will probably look up here for a solution anyway. To prevent firefox from scrolling through the history and make it scroll the site, you have to set the following settings:

mousewheel.horizscroll.withnokey.action = 1
mousewheel.horizscroll.withnokey.sysnumlines = true

You can edit them by opening about:config. (Tip taken from gentoo wiki.)

Links

Synaptics TouchPad driver for XOrg/XFree86 : [1]