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PSM(4)                 FreeBSD Kernel Interfaces Manual                 PSM(4)

     psm -- PS/2 mouse style pointing device driver

     options KBD_RESETDELAY=N
     options KBD_MAXWAIT=N
     options PSM_DEBUG=N
     options KBDIO_DEBUG=N
     device psm

     In /boot/device.hints:"atkbdc"

     The psm driver provides support for the PS/2 mouse style pointing device.
     Currently there can be only one psm device node in the system.  As the
     PS/2 mouse port is located at the auxiliary port of the keyboard con-
     troller, the keyboard controller driver, atkbdc, must also be configured
     in the kernel.  Note that there is currently no provision of changing the
     irq number.

     Basic PS/2 style pointing device has two or three buttons.  Some devices
     may have a roller or a wheel and/or additional buttons.

   Device Resolution
     The PS/2 style pointing device usually has several grades of resolution,
     that is, sensitivity of movement.  They are typically 25, 50, 100 and 200
     pulse per inch.  Some devices may have finer resolution.  The current
     resolution can be changed at runtime.  The psm driver allows the user to
     initially set the resolution via the driver flag (see DRIVER
     CONFIGURATION) or change it later via the ioctl(2) command MOUSE_SETMODE
     (see IOCTLS).

   Report Rate
     Frequency, or report rate, at which the device sends movement and button
     state reports to the host system is also configurable.  The PS/2 style
     pointing device typically supports 10, 20, 40, 60, 80, 100 and 200
     reports per second.  60 or 100 appears to be the default value for many
     devices.  Note that when there is no movement and no button has changed
     its state, the device will not send anything to the host system.  The
     report rate can be changed via an ioctl call.

   Operation Levels
     The psm driver has three levels of operation.  The current operation
     level can be set via an ioctl call.

     At the level zero the basic support is provided; the device driver will
     report horizontal and vertical movement of the attached device and state
     of up to three buttons.  The movement and status are encoded in a series
     of fixed-length data packets (see Data Packet Format).  This is the
     default level of operation and the driver is initially at this level when
     opened by the user program.

     The operation level one, the `extended' level, supports a roller (or
     wheel), if any, and up to 11 buttons.  The movement of the roller is
     reported as movement along the Z axis.  8 byte data packets are sent to
     the user program at this level.

     At the operation level two, data from the pointing device is passed to
     the user program as is.  Modern PS/2 type pointing devices often use pro-
     prietary data format.  Therefore, the user program is expected to have
     intimate knowledge about the format from a particular device when operat-
     ing the driver at this level.  This level is called `native' level.

   Data Packet Format
     Data packets read from the psm driver are formatted differently at each
     operation level.

     A data packet from the PS/2 mouse style pointing device is three bytes
     long at the operation level zero:

     Byte 1
             bit 7  One indicates overflow in the vertical movement count.
             bit 6  One indicates overflow in the horizontal movement count.
             bit 5  Set if the vertical movement count is negative.
             bit 4  Set if the horizontal movement count is negative.
             bit 3  Always one.
             bit 2  Middle button status; set if pressed.  For devices without
                    the middle button, this bit is always zero.
             bit 1  Right button status; set if pressed.
             bit 0  Left button status; set if pressed.
     Byte 2  Horizontal movement count in two's complement; -256 through 255.
             Note that the sign bit is in the first byte.
     Byte 3  Vertical movement count in two's complement; -256 through 255.
             Note that the sign bit is in the first byte.

     At the level one, a data packet is encoded in the standard format
     MOUSE_PROTO_SYSMOUSE as defined in mouse(4).

     At the level two, native level, there is no standard on the size and for-
     mat of the data packet.

     The psm driver can somewhat `accelerate' the movement of the pointing
     device.  The faster you move the device, the further the pointer travels
     on the screen.  The driver has an internal variable which governs the
     effect of the acceleration.  Its value can be modified via the driver
     flag or via an ioctl call.

   Device Number
     The minor device number of the psm is made up of:

           minor = (`unit' << 1) | `non-blocking'

     where `unit' is the device number (usually 0) and the `non-blocking' bit
     is set to indicate ``do not block waiting for mouse input, return immedi-
     ately''.  The `non-blocking' bit should be set for XFree86, therefore the
     minor device number usually used for XFree86 is 1.  See FILES for device
     node names.

   Kernel Configuration Options
     There are following kernel configuration options to control the psm
     driver.  They may be set in the kernel configuration file (see

            The psm driver will attempt to reset the pointing device during
            the boot process.  It sometimes takes a long while before the
            device will respond after reset.  These options control how long
            the driver should wait before it eventually gives up waiting.  The
            driver will wait X * Y msecs at most.  If the driver seems unable
            to detect your pointing device, you may want to increase these
            values.  The default values are 200 msec for X and 5 for Y.

            Sets the debug level to N.  The default debug level is zero.  See
            DIAGNOSTICS for debug logging.

   Driver Flags
     The psm driver accepts the following driver flags.  Set them in
     /boot/device.hints (see EXAMPLES below).

     bit 0..3 RESOLUTION
            This flag specifies the resolution of the pointing device.  It
            must be zero through four.  The greater the value is, the finer
            resolution the device will select.  Actual resolution selected by
            this field varies according to the model of the device.  Typical
            resolutions are:

            1 (low)            25 pulse per inch (ppi)
            2 (medium low)     50 ppi
            3 (medium high)    100 ppi
            4 (high)           200 ppi

            Leaving this flag zero will selects the default resolution for the
            device (whatever it is).

     bit 4..7 ACCELERATION
            This flag controls the amount of acceleration effect.  The smaller
            the value of this flag is, more sensitive the movement becomes.
            The minimum value allowed, thus the value for the most sensitive
            setting, is one.  Setting this flag to zero will completely dis-
            ables the acceleration effect.

     bit 8 NOCHECKSYNC
            The psm driver tries to detect the first byte of the data packet
            by checking the bit pattern of that byte.  Although this method
            should work with most PS/2 pointing devices, it may interfere with
            some devices which are not so compatible with known devices.  If
            you think your pointing device is not functioning as expected, and
            the kernel frequently prints the following message to the console,

                  psmintr: out of sync (xxxx != yyyy).

            set this flag to disable synchronization check and see if it

     bit 9 NOIDPROBE
            The psm driver will not try to identify the model of the pointing
            device and will not carry out model-specific initialization.  The
            device should always act like a standard PS/2 mouse without such
            initialization.  Extra features, such as wheels and additional
            buttons, will not be recognized by the psm driver.

     bit 10 NORESET
            When this flag is set, the psm driver will not reset the pointing
            device when initializing the device.  If the FreeBSD kernel is
            started after another OS has run, the pointing device will inherit
            settings from the previous OS.  However, because there is no way
            for the psm driver to know the settings, the device and the driver
            may not work correctly.  The flag should never be necessary under
            normal circumstances.

     bit 11 FORCETAP
            Some pad devices report as if the fourth button is pressed when
            the user `taps' the surface of the device (see CAVEATS).  This
            flag will make the psm driver assume that the device behaves this
            way.  Without the flag, the driver will assume this behavior for
            ALPS GlidePoint models only.

            This flag makes psm driver ignore certain error conditions when
            probing the PS/2 mouse port.  It should never be necessary under
            normal circumstances.

     bit 13 HOOKRESUME
            The built-in PS/2 pointing device of some laptop computers is
            somehow not operable immediately after the system `resumes' from
            the power saving mode, though it will eventually become available.
            There are reports that stimulating the device by performing I/O
            will help waking up the device quickly.  This flag will enable a
            piece of code in the psm driver to hook the `resume' event and
            exercise some harmless I/O operations on the device.

            This flag adds more drastic action for the above problem.  It will
            cause the psm driver to reset and re-initialize the pointing
            device after the `resume' event.  It has no effect unless the
            HOOKRESUME flag is set as well.

     Extended support for Synaptics touchpads can be enabled by setting
     hw.psm.synaptics_support to 1 at boot-time.  This will enable psm to han-
     dle packets from guest devices (sticks) and extra buttons.

     There are a few ioctl(2) commands for mouse drivers.  These commands and
     related structures and constants are defined in <sys/mouse.h>.  General
     description of the commands is given in mouse(4).  This section explains
     the features specific to the psm driver.

     MOUSE_GETLEVEL int *level
     MOUSE_SETLEVEL int *level
            These commands manipulate the operation level of the psm driver.

     MOUSE_GETHWINFO mousehw_t *hw
            Returns the hardware information of the attached device in the
            following structure.

            typedef struct mousehw {
                int buttons;    /* number of buttons */
                int iftype;     /* I/F type */
                int type;       /* mouse/track ball/pad... */
                int model;      /* I/F dependent model ID */
                int hwid;       /* I/F dependent hardware ID */
            } mousehw_t;

            The buttons field holds the number of buttons on the device.  The
            psm driver currently can detect the 3 button mouse from Logitech
            and report accordingly.  The 3 button mouse from the other manu-
            facturer may or may not be reported correctly.  However, it will
            not affect the operation of the driver.

            The iftype is always MOUSE_IF_PS2.

            The type tells the device type: MOUSE_MOUSE, MOUSE_TRACKBALL,
            MOUSE_STICK, MOUSE_PAD, or MOUSE_UNKNOWN.  The user should not
            heavily rely on this field, as the driver may not always, in fact
            it is very rarely able to, identify the device type.

            The model is always MOUSE_MODEL_GENERIC at the operation level 0.
            It may be MOUSE_MODEL_GENERIC or one of MOUSE_MODEL_XXX constants
            at higher operation levels.  Again the psm driver may or may not
            set an appropriate value in this field.

            The hwid is the ID value returned by the device.  Known IDs

            0    Mouse (Microsoft, Logitech and many other manufacturers)
            2    Microsoft Ballpoint mouse
            3    Microsoft IntelliMouse

     MOUSE_SYN_GETHWINFO synapticshw_t *synhw
            Retrieves extra information associated with Synaptics Touchpads.
            Only available when hw.psm.synaptics_support has been enabled.

            typedef struct synapticshw {
                int infoMajor;      /* major hardware revision */
                int infoMinor;      /* minor hardware revision */
                int infoRot180;     /* touchpad is rotated */
                int infoPortrait;   /* touchpad is a portrait */
                int infoSensor;     /* sensor model */
                int infoHardware;   /* hardware model */
                int infoNewAbs;     /* supports the newabs format */
                int capPen;         /* can detect a pen */
                int infoSimpleC;    /* supports simple commands */
                int infoGeometry;   /* touchpad dimensions */
                int capExtended;    /* supports extended packets */
                int capSleep;       /* can be suspended/resumed */
                int capFourButtons; /* has four buttons */
                int capMultiFinger; /* can detect multiple fingers */
                int capPalmDetect;  /* can detect a palm */
                int capPassthrough; /* can passthrough guest packets */
            } synapticshw_t;

            See the Synaptics TouchPad Interfacing Guide for more information
            about the fields in this structure.

     MOUSE_GETMODE mousemode_t *mode
            The command gets the current operation parameters of the mouse

            typedef struct mousemode {
                int protocol;    /* MOUSE_PROTO_XXX */
                int rate;        /* report rate (per sec), -1 if unknown */
                int resolution;  /* MOUSE_RES_XXX, -1 if unknown */
                int accelfactor; /* acceleration factor */
                int level;       /* driver operation level */
                int packetsize;  /* the length of the data packet */
                unsigned char syncmask[2]; /* sync. bits */
            } mousemode_t;

            The protocol is MOUSE_PROTO_PS2 at the operation level zero and
            two.  MOUSE_PROTO_SYSMOUSE at the operation level one.

            The rate is the status report rate (reports/sec) at which the
            device will send movement report to the host computer.  Typical
            supported values are 10, 20, 40, 60, 80, 100 and 200.  Some mice
            may accept other arbitrary values too.

            The resolution of the pointing device must be one of MOUSE_RES_XXX
            constants or a positive value.  The greater the value is, the
            finer resolution the mouse will select.  Actual resolution
            selected by the MOUSE_RES_XXX constant varies according to the
            model of mouse.  Typical resolutions are:

            MOUSE_RES_LOW           25 ppi
            MOUSE_RES_MEDIUMLOW     50 ppi
            MOUSE_RES_MEDIUMHIGH    100 ppi
            MOUSE_RES_HIGH          200 ppi

            The accelfactor field holds a value to control acceleration fea-
            ture (see Acceleration).  It must be zero or greater.  If it is
            zero, acceleration is disabled.

            The packetsize field specifies the length of the data packet.  It
            depends on the operation level and the model of the pointing

            level 0    3 bytes
            level 1    8 bytes
            level 2    Depends on the model of the device

            The array syncmask holds a bit mask and pattern to detect the
            first byte of the data packet.  syncmask[0] is the bit mask to be
            ANDed with a byte.  If the result is equal to syncmask[1], the
            byte is likely to be the first byte of the data packet.  Note that
            this detection method is not 100% reliable, thus, should be taken
            only as an advisory measure.

     MOUSE_SETMODE mousemode_t *mode
            The command changes the current operation parameters of the mouse
            driver as specified in mode.  Only rate, resolution, level and
            accelfactor may be modifiable.  Setting values in the other field
            does not generate error and has no effect.

            If you do not want to change the current setting of a field, put
            -1 there.  You may also put zero in resolution and rate, and the
            default value for the fields will be selected.

     MOUSE_READDATA mousedata_t *data
     MOUSE_READSTATE mousedata_t *state
            These commands are not currently supported by the psm driver.

     MOUSE_GETSTATUS mousestatus_t *status
            The command returns the current state of buttons and movement
            counts as described in mouse(4).

     /dev/psm0   `non-blocking' device node
     /dev/bpsm0  `blocking' device node under devfs.

     In order to install the psm driver, you need to add

           device atkbdc
           device psm

     to your kernel configuration file, and put the following lines to


     If you add the following statement to /boot/device.hints,


     you will add the optional code to stimulate the pointing device after the
     `resume' event.


     The above line will set the device resolution high (4) and the accelera-
     tion factor to 2.

     At debug level 0, little information is logged except for the following
     line during boot process:

           psm0: device ID X

     where X the device ID code returned by the found pointing device.  See
     MOUSE_GETINFO for known IDs.

     At debug level 1 more information will be logged while the driver probes
     the auxiliary port (mouse port).  Messages are logged with the LOG_KERN
     facility at the LOG_DEBUG level (see syslogd(8)).

           psm0: current command byte:xxxx
           kbdio: TEST_AUX_PORT status:0000
           kbdio: RESET_AUX return code:00fa
           kbdio: RESET_AUX status:00aa
           kbdio: RESET_AUX ID:0000
           psm: status 00 02 64
           psm0 irq 12 on isa
           psm0: model AAAA, device ID X, N buttons
           psm0: config:00000www, flags:0000uuuu, packet size:M
           psm0: syncmask:xx, syncbits:yy

     The first line shows the command byte value of the keyboard controller
     just before the auxiliary port is probed.  It usually is 4D, 45, 47 or
     65, depending on how the motherboard BIOS initialized the keyboard con-
     troller upon power-up.

     The second line shows the result of the keyboard controller's test on the
     auxiliary port interface, with zero indicating no error; note that some
     controllers report no error even if the port does not exist in the sys-
     tem, however.

     The third through fifth lines show the reset status of the pointing
     device.  The functioning device should return the sequence of FA AA <ID>.
     The ID code is described above.

     The seventh line shows the current hardware settings.  These bytes are
     formatted as follows:

     Byte 1
             bit 7  Reserved.
             bit 6  0 - stream mode, 1 - remote mode.  In the stream mode, the
                    pointing device sends the device status whenever its state
                    changes.  In the remote mode, the host computer must
                    request the status to be sent.  The psm driver puts the
                    device in the stream mode.
             bit 5  Set if the pointing device is currently enabled.  Other-
                    wise zero.
             bit 4  0 - 1:1 scaling, 1 - 2:1 scaling.  1:1 scaling is the
             bit 3  Reserved.
             bit 2  Left button status; set if pressed.
             bit 1  Middle button status; set if pressed.
             bit 0  Right button status; set if pressed.
     Byte 2
             bit 7    Reserved.
             bit 6..0
                      Resolution code: zero through three.  Actual resolution
                      for the resolution code varies from one device to
     Byte 3  The status report rate (reports/sec) at which the device will
             send movement report to the host computer.

     Note that the pointing device will not be enabled until the psm driver is
     opened by the user program.

     The rest of the lines show the device ID code, the number of detected
     buttons and internal variables.

     At debug level 2, much more detailed information is logged.

     Many pad devices behave as if the first (left) button were pressed if the
     user `taps' the surface of the pad.  In contrast, some pad products, e.g.
     some versions of ALPS GlidePoint and Interlink VersaPad, treat the tap-
     ping action as fourth button events.

     It is reported that Interlink VersaPad requires both HOOKRESUME and
     INITAFTERSUSPEND flags in order to recover from suspended state.  These
     flags are automatically set when VersaPad is detected by the psm driver.

     Some PS/2 mouse models from MouseSystems require to be put in the high
     resolution mode to work properly.  Use the driver flag to set resolution.

     There is not a guaranteed way to re-synchronize with the first byte of
     the packet once we are out of synchronization with the data stream.  How-
     ever, if you are using the XFree86 server and experiencing the problem,
     you may be able to make the X server synchronize with the mouse by
     switching away to a virtual terminal and getting back to the X server,
     unless the X server is accessing the mouse via moused(8).  Clicking any
     button without moving the mouse may also work.

     ioctl(2), syslog(3), atkbdc(4), mouse(4), mse(4), sysmouse(4), moused(8),

     Synaptics TouchPad Interfacing Guide,

     The psm driver is based on the work done by quite a number of people,
     including Eric Forsberg, Sandi Donno, Rick Macklem, Andrew Herbert,
     Charles Hannum, Shoji Yuen and Kazutaka Yokota to name the few.

     This manual page was written by Kazutaka Yokota <>.

     The ioctl command MOUSEIOCREAD has been removed.  It was never functional

     Enabling the extended support for Synaptics touchpads has been reported
     to cause problems with responsivity on some (newer) models of Synaptics
     hardware, particularly those with guest devices.

FreeBSD 6.2                   September 29, 2004                   FreeBSD 6.2


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