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PMS(4) Device Drivers Manual PMS(4)

pms — PS/2 auxiliary port mouse driver

pckbc* at isa?
pms* at pckbc?
wsmouse* at pms?


options PMS_DISABLE_POWERHOOK
options PMS_SYNAPTICS_TOUCHPAD
options PMS_ELANTECH_TOUCHPAD
options PMS_ALPS_TOUCHPAD

The pms driver provides an interface to PS/2 auxiliary port mice within the wscons(4) framework. Parent device in terms of the autoconfiguration framework is pckbc(4), the PC keyboard controller. “pms” is a generic driver which supports mice using common variants of the PS/2 protocol, including wheel mice of the “IntelliMouse” breed. Wheel movements are mapped to a third (z-) axis. The driver is believed to work with both 3-button and 5-button mice with scroll wheels. Mice which use other protocol extensions are not currently supported, but might be if protocol documentation could be found. Mouse related data are accessed by wsmouse(4) devices.

The pms driver has been updated to attempt to renegotiate mouse protocol after seeing suspicious or defective mouse protocol packets, or unusual delays in the middle of a packet; this should improve the chances that a mouse will recover after being switched away or reset (for instance, by a console switch).

The PMS_DISABLE_POWERHOOK kernel option disables PS/2 reset on resume.

In addition, the pms driver supports the “Synaptics”, “Elantech” and “ALPS” touchpads in native mode, enabled with the PMS_SYNAPTICS_TOUCHPAD, PMS_ELANTECH_TOUCHPAD and PMS_ALPS_TOUCHPAD kernel options. This allows the driver to take advantage of extra features available on Synaptics, Elantech and ALPS Touchpads.

The following sysctl(8) variables control behavior of Synaptics touchpads:

If the touchpad reports the existence of extra ("Up/Down") buttons, this value determines what kind of mouse events they should generate. On certain clickpads, the Up/Down buttons may be physical buttons that can be used instead of pressing the pad down, or used as additional buttons.
  • If set to 0, Up/Down events generate button 4 and 5 clicks.
  • If set to 1, Up/Down events generate middle button clicks.
  • If set to 2, the Up and Down buttons are used for Z-axis emulation, which more closely resembles how mouse wheels operate.
  • If set to 3 (default), Up/Down events generate left/right clicks.
When the Up/Down buttons are used for Z-axis emulation, this value specifies the emulated delta-Z value per click.
Gestures will not be recognised if the finger moves by more than this amount between taps.
Gestures will not be recognised if the number of packets (at 80 packets per second) between taps exceeds this value.
 
 
 
These values define a border around the touchpad which will be used for edge motion emulation during a drag gesture. If a drag gesture is in progress and the finger moves into this border, the driver will behave as if the finger continues to move in the same direction beyond the edge of the touchpad.
This specifies the pointer speed when edge motion is in effect.
The driver will ignore new finger events until the reported pressure exceeds this value.
The driver will assume a finger remains on the touchpad until the reported pressure drops below this value.
More recent touchpads can report the presence of more than one finger on the pad. This value determines how such events are used.
  • If set to 0 (default), two-finger events are ignored.
  • If set to 1, two-finger events generate a right button click.
  • If set to 2, two-finger events generate a middle button click.
 
 
Scale factor used to divide movement deltas derived from Synaptics coordinates (0-6143) to yield more reasonable values (default 16 for x and y, 1 for z).
 
 
Limits pointer rate of change (after scaling) per reported movement event (default 32 for x and y, 2 for z).
Movements of less than this value (in Synaptics coordinates) are ignored (default 4).
Sets the top edge of the button emulation region on a clickpad. Since a clickpad only reports left clicks this region is used to emulate two or three buttons by detecting the finger location and reporting either a button 2 or button 3 click iff the click occurs within the region bounded by button_boundary and the bottom of the clickpad.
This defines the left hand edge of the button 3 region. If a click occurs in the region bounded by button_boundary, button3_edge and the right hand edge of the click pad then the click will be reported as a button3 event. Button 3 emulation can be disabled by setting button3_edge to the right hand edge of the clickpad.
This defines the left hand edge of the button 2 region. The button 2 region is bounded by button2_edge, button3_edge and button_boundary. If a click occurs in this region then it will be reported as a button2 event. For completeness, the region between the left hand side of the clickpad, button2_edge and button_boundary will be reported as a button1 event as will any clicks that occur outside the button emulation region.
The minimum finger width at which the driver will start reporting vertical movements as Z axis events. Effectively, this emulates a mouse scroll wheel by the user using two fingers together on the click pad. The default value is 5, this value cannot be less than 5 due to the way the clickpad reports finger width.
The maximum finger width at which the driver will report finger movement as Z axis events. The default value is 12 and cannot be greater than 14.
This defines the number of packets to continue with the Z axis emulation. Due to the nature of the clickpad maintaining constant contact can be difficult. This hysteresis value prevents the driver flipping between two finger scroll and normal mouse movement erratically. Each time a valid finger scroll width is detected the packet count is reset. If this variable is set too high then mouse movements will be interpreted as Z-axis events after the two finger scoll has finished. If the variable is set too low then there will be mouse movements observed during the two finger scroll.
This causes Y-axis movement on the "passthrough device" (e.g. the TrackPoint on ThinkPads) to result in scrolling events instead of Y-axis movement when the middle button is held.

The following sysctl(8) variables control behavior of Elantech touchpads:

 
Increased values improve the accuracy of X, Y, and Z-axis reporting at the expense of slower mouse movement (default 2 for xy, and 3 for z).

For Elantech touchpads, the Z-axis is emulated using two-finger Y-axis reporting.

The following sysctl(8) variables control behavior of ALPS touchpads:

 
Decreased values improve the accuracy of X and Y-axis reporting at the expense of slower mouse movement (default 2 for touchpad and 1 for TrackStick).

pckbc(4), ums(4), wsmouse(4)

The pms driver was originally written by Christopher G. Demetriou. The changes to merge the “IntelliMouse” protocol in, and reset the mouse in the event of protocol problems, were contributed by Peter Seebach. Special thanks to Ray Trent, at Synaptics, who contributed valuable insight into how to identify bogus mouse data. The changes to add “Synaptics” pad support were by Ales Krenek, Kentaro A. Kurahone, and Steve C. Woodford. The changes to add “Elantech” pad support were by Jared D. McNeill.

It is possible for the driver to mistakenly negotiate the non-scroll-wheel protocol, after which it is unlikely to recover until the device is closed and reopened.

The “Elantech” pad code only supports trackpads with firmware version 2.48 or above.

October 1, 2020 NetBSD-9.2