synaptics(5) - Linux man page
synaptics - Synaptics touchpad driver for XOrg/XFree86.
This is a driver for the Synaptics TouchPad for XOrg/XFree86 4.x. A Synaptics touchpad by default operates in compatibility mode by emulating a standard mouse. However, by using a dedicated driver, more advanced features of the touchpad becomes available, such as:
- Movement with adjustable, non-linear acceleration and speed.
- Button events through short touching of the touchpad.
- Double-Button events through double short touching of the touchpad.
- Dragging through short touching and holding down the finger on the touchpad.
- Middle and right button events on the upper and lower corner of the touchpad.
- Vertical scrolling (button four and five events) through moving the finger on the right side of the touchpad.
- The up/down button sends button four/five events.
- Horizontal scrolling (button six and seven events) through moving the finger on the lower side of the touchpad.
- The multi-buttons send button four/five events, and six/seven events for horizontal scrolling.
- Adjustable finger detection.
- Multifinger taps: two finger for middle button and three finger for right button events. (Needs hardware support. Not all models implement this feature.)
- Run-time configuration using shared memory. This means you can change parameter settings without restarting the X server.
Note that depending on the touchpad firmware, some of these features might be available even without using the synaptics driver. Note also that some functions are not available on all touchpad models, because they need support from the touchpad hardware/firmware. (Multifinger taps for example.)
The driver behavior can be configured with parameters. These parameters are options in the InputDevice section in the XOrg/XFree86 config file. See the INSTALL file for a working example. If you have the SHMConfig parameter enabled, these parameters can also be changed at runtime with the synclient(1) program. The following parameters are available:
- Device (String)
- Synaptics device.
- Protocol (String)
auto-dev automatic, default psaux raw event linux 2.6 kernel events psm FreeBSD psm driver
- SHMConfig (Bool)
- Switch on/off shared memory for configuration.
- LeftEdge (Integer)
- X coordinate for left edge.
- RightEdge (Integer)
- X coordinate for right edge.
- TopEdge (Integer)
- Y coordinate for top edge.
- BottomEdge (Integer)
- Y coordinate for bottom edge.
- FingerLow (Integer)
- When finger pressure drops below this value, the driver counts it as a release.
- FingerHigh (Integer)
- When finger pressure goes above this value, the driver counts it as a touch.
- MaxTapTime (Integer)
- Maximum time (in milliseconds) for detecting a tap.
- MaxTapMove (Integer)
- Maximum movement of the finger for detecting a tap.
- MaxDoubleTapTime (Integer)
- Maximum time (in milliseconds) for detecting a double tap.
- ClickTime (Integer)
- The duration of the mouse click generated by tapping.
- FastTaps (Bool)
- Makes the driver react faster to a single tap, but also makes double clicks caused by double tapping slower.
- VertScrollDelta (Integer)
- Move distance of the finger for a scroll event.
- HorizScrollDelta (Integer)
- Move distance of the finger for a scroll event.
- EdgeMotionMinZ (Integer)
- Finger pressure at which minimum edge motion speed is set.
- EdgeMotionMaxZ (Integer)
- Finger pressure at which maximum edge motion speed is set.
- EdgeMotionMinSpeed (Integer)
- Slowest setting for edge motion speed.
- EdgeMotionMaxSpeed (Integer)
- Fastest setting for edge motion speed.
- EdgeMotionUseAlways (Bool)
- If on, edge motion is also used for normal movements. If off, egde motion is used only when dragging.
- Repeater (String)
- Repeater device.
- MinSpeed (Float)
- Minimum speed factor.
- MaxSpeed (Float)
- Maximum speed factor.
- AccelFactor (Float)
- Acceleration factor.
- UpDownScrolling (Bool)
- If on, the up/down buttons generate button 4/5 events. If off, the up button generates a double click and the down button generates a button 2 event.
- LeftRightScrolling (Bool)
- If on, the left/right buttons generate button 6/7 events. If off, the left/right buttons both generate button 2 events.
- UpDownRepeat (Bool)
- If on, and the up/down buttons are used for scrolling (UpDownScrolling), these buttons will send auto-repeating 4/5 events, with the delay between repeats determined by ScrollButtonRepeat.
- LeftRightRepeat (Bool)
- If on, and the left/right buttons are used for scrolling (LeftRightScrolling), these buttons will send auto-repeating 6/7 events, with the delay between repeats determined by ScrollButtonRepeat.
- ScrollButtonRepeat (Integer)
- The number of milliseconds between repeats of button events 4-7 from the up/down/left/right scroll buttons.
- EmulateMidButtonTime (Integer)
- Maximum time (in milliseconds) for middle button emulation.
- TouchpadOff (Integer)
- Switch off the touchpad. Valid values are:
0 Touchpad is enabled 1 Touchpad is switched off 2 Only tapping and scrolling is switched off
- GuestMouseOff (Bool)
- Switch on/off guest mouse (often a stick).
- LockedDrags (Bool)
- If off, a tap and drag gesture ends when you release the finger. If on, the gesture is active until you tap a second time.
- RTCornerButton (Integer)
- Which mouse button is reported on a right top corner tap. Set to 0 to disable.
- RBCornerButton (Integer)
- Which mouse button is reported on a right bottom corner tap. Set to 0 to disable.
- LTCornerButton (Integer)
- Which mouse button is reported on a left top corner tap. Set to 0 to disable.
- LBCornerButton (Integer)
- Which mouse button is reported on a left bottom corner tap. Set to 0 to disable.
- TapButton1 (Integer)
- Which mouse button is reported on a non-corner one-finger tap. Set to 0 to disable.
- TapButton2 (Integer)
- Which mouse button is reported on a non-corner two-finger tap. Set to 0 to disable.
- TapButton3 (Integer)
- Which mouse button is reported on a non-corner three-finger tap. Set to 0 to disable.
- CircularScrolling (Bool)
- If on, circular scrolling is used.
- CircScrollDelta (Float)
- Move angle (radians) of finger to generate a scroll event.
- CircScrollTrigger (Integer)
- Trigger region on the touchpad to start circular scrolling
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
- CircularPad (Bool)
- Instead of being a rectangle, the edge is the ellipse enclosed by the Left/Right/Top/BottomEdge parameters. For circular touchpads.
- PalmDetect (Bool)
- If palm detection should be enabled. Note that this also requires hardware/firmware support from the touchpad.
- PalmMinWidth (Integer)
- Minimum finger width at which touch is considered a palm.
- PalmMinZ (Integer)
- Minimum finger pressure at which touch is considered a palm.
- CoastingSpeed (Float)
- Coasting threshold scrolling speed. 0 disables coasting.
The LeftEdge, RightEdge, TopEdge and BottomEdge parameters are used to define the edge and corner areas of the touchpad. The parameters split the touchpad area in 9 pieces, like this:
|Physical top edge|
|Physical left edge|
Coordinates to the left of LeftEdge are part of the left edge (areas 1, 4 and 7), coordinates to the left of LeftEdge and above TopEdge (area 1) are part of the upper left corner, etc. A good way to find appropriate edge parameters is to enable the SHMConfig option and run "synclient -m 1" to see the x/y coordinates corresponding to different positions on the touchpad.
A tap event happens when the finger is touched and released in a time interval shorter than MaxTapTime, and the touch and release coordinates are less than MaxTapMove units apart. A "touch" event happens when the Z value goes above FingerHigh, and an "untouch" event happens when the Z value goes below FingerLow.
The MaxDoubleTapTime parameter has the same function as the MaxTapTime parameter, but for the second, third, etc tap in a tap sequence. If you can't perform double clicks fast enough (for example, xmms depends on fast double clicks), try reducing this parameter. If you can't get word selection to work in xterm (ie button down, button up, button down, move mouse), try increasing this parameter.
The ClickTime parameter controls the delay between the button down and button up X events generated in response to a tap event. A too long value can cause undesirable autorepeat in scroll bars and a too small value means that visual feedback from the gui application you are interacting with is harder to see.
The MinSpeed, MaxSpeed and AccelFactor parameters control the pointer motion speed. The speed value defines the scaling between touchpad coordinates and screen coordinates. When moving the finger very slowly, the MinSpeed value is used, when moving very fast the MaxSpeed value is used. When moving the finger at moderate speed, you get a pointer motion speed somewhere between MinSpeed and MaxSpeed. If you don't want any acceleration, set MinSpeed and MaxSpeed to the same value.
The MinSpeed, MaxSpeed and AccelFactor parameters don't have any effect on scrolling speed. Scrolling speed is determined solely from the VertScrollDelta and HorizScrollDelta parameters. To disable vertical or horizontal scrolling, set VertScrollDelta or HorizScrollDelta to zero.
When hitting an egde, movement can be automatically continued. If EdgeMotionUseAlways is false, edge motion is only used when dragging. With EdgeMotionUseAlways set to true, it is also used for normal cursor movements.
Edge motion speed is calculated by taking into account the amount of pressure applied to the touchpad. The sensitivity can be adjusted using the EdgeMotion parameters. If the pressure is below EdgeMotionMinZ, EdgeMotionMinSpeed is used, and if the pressure is greater than EdgeMotionMaxZ, EdgeMotionMaxSpeed is used. For a pressure value between EdgeMotionMinZ and EdgeMotionMaxZ, the speed is increased linearly.
Since most synaptics touchpad models don't have a button that corresponds to the middle button on a mouse, the driver can emulate middle mouse button events. If you press both the left and right mouse buttons at almost the same time (no more than EmulateMidButtonTime milliseconds apart) the driver generates a middle mouse button event.
Circular scrolling acts like a scrolling wheel on the trackpad. Scrolling is engaged when a drag starts in the given CircScrollTrigger region, which can be all edges, a particular side, or a particular corner. Once scrolling is engaged, moving your finger in clockwise circles around the trackpad will generate scroll down events and counter clockwise scroll up events. Lifting your finger will disengage circular scrolling. Use tight circles near the center of the pad for fast scrolling and large circles for better control. When used together with vertical scrolling, hitting the upper or lower right corner will seamlessly switch over from vertical to circular scrolling.
Coasting is enabled by setting the CoastingSpeed parameter to a non-zero value. When coasting is enabled, horizontal/vertical scrolling can continue after the finger is released from the lower/right edge of the touchpad. The driver computes the scrolling speed corresponding to the finger speed immediately before the finger leaves the touchpad. If this scrolling speed is larger than the CoastingSpeed parameter (measured in scroll events per second), the scrolling will continue with the same speed in the same direction until the finger touches the touchpad again.
Peter Osterlund <email@example.com> and many others.