.\"	$Id: psm.4,v 1.2 1996/12/26 16:16:15 wosch Exp $
.\"
.Dd Nov 8, 1996
.Dt PSM 4 i386
.Os
.Sh NAME
.Nm psm
.Nd
PS/2 mouse style pointing device driver
.Sh SYNOPSIS
.\".Cd "options PSM_NOCHECKSYNC"
.\".Cd "options PSM_NOEMULATION"
.\".Cd "options" \&"PSM_ACCEL=N\&"
.Cd "options" \&"PSM_RESETDELAY=N\&"
.Cd "options" \&"PSM_MAXWAIT=N\&"
.Cd "options" \&"PSM_DEBUG=N\&"
.Cd "device psm0 at isa? port" \&"IO_KBD\&" conflicts tty irq 12 vector psmintr
.Sh DESCRIPTION
The
.Nm
driver provides support for the PS/2 mouse style pointing device.

Note that 
.Nm port \&"IO_KBD\&"
and
.Nm conflicts
is required 
as the PS/2 mouse port is located
at the auxially port of the keyboard controller, thus, the 
.Nm
driver has to share the port with the keyboard driver.
Note also that there is currently no provision of changing the 
.Nm irq
number.
.Pp
A series of data packets is read from the
.Nm
driver. A data packet from the PS/2 mouse style pointing device
is three bytes long:
.Pp
.Bl -tag -width Byte_1
.It Byte 1 
.Bl -tag -width bit_7
.It bit 7
One indicates overflow in the vertical movement count.
.It bit 6
One indicates overflow in the horizontal movement count.
.It bit 5
Set if the vertical movement count is negative.
.It bit 4
Set if the horizontal movement count is negative.
.It bit 3
Always one?.
.It bit 2
Middle button status; set if pressed. For the device without the middle
button, this bit is always one?.
.It bit 1
Right button status; set if pressed.
.It bit 0
Left button status; set if pressed.
.El
.It Byte 2
Horizontal movement count in two's compliment;
-128 through 127.
.It Byte 3
Vertical movement count in two's compliment;
-128 through 127.
.El
.Pp
The minor device number of the
.Nm
is made up of:
.Bd -literal -offset indent
minor = (`unit' << 1) | `non-blocking'
.Ed
.Pp
where `unit' is the device number (usually 0) and the `non-blocking' bit
is set to indicate "don't block waiting for mouse input, return immediately".
The `non-blocking' bit should be set for \fIXFree86\fP, 
therefore the minor device number usually used for \fIXFree86\fP is 1.
.Sh KERNEL CONFIGURATION
There are following options to control the
.Nm
device.
.Bl -tag -width MOUSE
.\".It Em PSM_NOCHECKSYNC
.\"By default, the driver tries to detect the first byte of 
.\"the three-byte-long data packet. However, this may not always be 
.\"reliable. This feature will be turned off by specifying this option.
.\".It Em PSM_NOEMULATION
.\"The
.\".Nm
.\"driver can emulate the Microsoft Serial Mouse's three-byte
.\"data packet and the Mouse Systems Corp's five-byte data packet
.\"when data is read by user programs, if so specified by the
.\".Fn ioctl
.\"command
.\".Dv MOUSE_SETMODE .
.\"The emulation will be disabled with this option.
.\".It Em PSM_ACCEL=N
.\"The
.\".Nm
.\"driver somewhat `accelerates' the movement of the pointing device.
.\"That is, the faster you move the device, the longer the pointer 
.\"travels on the screen. This option controls the amount of acceleration.
.\"The smaller
.\".Fa N
.\"is, more sensitive the movement becomes. The default value is 2.
.\"The minimum value, thus the value for the most sensitive setting, allowed
.\"is 1. Setting this option to zero will completely disables the
.\"acceleration effect.
.It Em PSM_RESETDELAY=X, PSM_MAXWAIT=Y
The
.Nm
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
.Fa X
*
.Fa 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 
.Fa X
and 5
for
.Fa Y .
.It Em PSM_DEBUG=N
Sets the debug level to 
.Fa N .
The default debug level is zero. See
.Em DIAGNOSTICS
for debug logging.
.El
.\".Sh IOCTL
.\".Bl -tag -width MOUSE
.\".It Dv MOUSE_GETSTATE, MOUSECREAD
.\"The command returns the current mouse state in the following structure
.\"and remove the state information from the internal queue.
.\".Bd -literal
.\"struct mouseinfo {
.\"    unsigned char status;    /* button and motion status bits */
.\"    char xmotion;            /* horizontal motion count */
.\"    char ymotion;            /* vertical motion count */
.\"};
.\".Ed
.\".Pp
.\"The
.\".Dv status
.\"holds a ORed value of the following constants:
.\".Bl -tag -width BUTSTATMASK
.\".It Dv BUT1STAT
.\"The Button 1 (left button) is pressed.
.\".It Dv BUT2STAT
.\"The Button 2 (middle button) is pressed.
.\".It Dv BUT3STAT
.\"The Button 3 (right button) is pressed.
.\".It Dv BUT1CHNG
.\"The state of the button 1 has changed.
.\".It Dv BUT2CHNG
.\"The state of the button 2 has changed.
.\".It Dv BUT3CHNG
.\"The state of the button 3 has changed.
.\".It Dv MOVEMENT
.\"Either
.\".Dv xmotion
.\"or
.\".Dv ymotion
.\"is not zero.
.\".El
.\".Pp
.\"Note that these commands and
.\".Fn read
.\"operation on the 
.\".Nm
.\"driver uses the same internal queue. Therefore, interleaving
.\"these commands and 
.\".Fn read
.\"operation is not recommended.
.\".It Dv MOUSE_GETINFO
.\"Returns the hardware information in the following structure:
.\".Bd -literal
.\"typedef struct mousehw {
.\"    int buttons;    /* number of buttons */
.\"    int iftype;     /* I/F type */
.\"    int type;       /* mouse/track ball/pad... */
.\"    int hwid;       /* I/F dependent hardware ID */
.\"} mousehw_t;
.\".Ed
.\".Pp
.\"The
.\".Dv iftype
.\"is 
.\".Dv MOUSE_IF_PS2
.\"for the 
.\".Nm
.\"driver. The
.\".Dv type
.\"tells the device type:
.\".Dv MOUSE_MOUSE ,
.\".Dv MOUSE_TRACKBALL ,
.\".Dv MOUSE_STICK ,
.\".Dv MOUSE_PAD ,
.\"or
.\".Dv MOUSE_UNKNOWN .
.\"The user should not heavily rely on this field, as the
.\".Nm
.\"driver may not always, in fact it is very rarely able to, identify
.\"the device type.
.\"The
.\".Dv hwid
.\"is the ID value returned by the pointing device. See below for possible
.\"values.
.\".It Dv MOUSE_GETMODE, MOUSE_SETMODE
.\"The commands get and set operation mode of the 
.\".Nm
.\"driver.
.\".Bd -literal
.\"typedef struct mousemode {
.\"    int protocol;    /* MOUSE_PROTO_XXX */
.\"    int rate;        /* report rate (per sec), -1 if unknown */
.\"    int resolution;  /* ppi, -1 if unknown */
.\"    int accelfactor; /* acceleration factor (must be 1 or greater) */
.\"} mousemode_t;
.\".Ed
.\".Pp
.\"The
.\".Dv protocol
.\"selects the format with which the device status is returned by
.\".Fn read .
.\"The default is 
.\".Dv MOUSE_PROTO_PS2 ,
.\"that is, the data byte from the pointing device is returned as is.
.\"Other possible values are:
.\".Dv MOUSE_PROTO_MSS
.\"and
.\".Dv MOUSE_PROTO_MSC ,
.\"which specifies Microsoft Serial Mouse three-byte format and
.\"Mouse Systems Corp.'s five-byte format respectively.
.\"The
.\".Dv rate
.\"is the status report rate (reports/sec) at which the device will send 
.\"movement report to the host computer.
.\"The
.\".Dv resolution
.\"of the pointing device is expressed in pulse-per-inch. Setting
.\"this field to an arbitrary value may not always work.
.\"The
.\".Dv accelfactor
.\"holds a value to control acceleration feature (see description on
.\".Em PSM_ACCEL
.\"above). It must be one or greater.
.\"If acceleration is disabled by the kernel configuration, 
.\"setting this field has no effect.
.\".El
.Sh DIAGNOSTICS
.Pp
At debug level 0, little information is logged except for the following
line during boot process:
.Bd -literal -offset indent
psm0: device ID X, N buttons?
.Ed
.Pp
where
.Fa X
the device ID code returned by the found pointing device.
Known IDs include:
.Bl -tag -width 0__
.It Em 0
Mouse (Microsoft, Logitech and many other manufacturers)
.It Em 2
Microsoft Ballpoint mouse
.El
.Pp
Currently the
.Nm
driver can detect the 3 button mouse from Logitech and report
accordingly.
The 3 button mouse from the other manufacturer may or may not be 
reported correctly. However, it will not affect the operation of
the driver.
.Pp
At debug level 1 more information will be logged
while the driver probes the auxially (mouse) port.
Messages are logged with the LOG_KERN facility at the LOG_DEBUG level.
(See 
.Xr syslogd 8 . )
.Bd -literal -offset indent
psm0: current command byte:xxxx
psm: TEST_AUX_PORT status:0000
psm: RESET_AUX return code:00fa
psm: RESET_AUX status:00aa
psm: RESET_AUX ID:0000
psm: status xx yy zz (get_mouse_buttons)
psm0: status 00 03 64
.Ed
.Pp
The first line shows the command byte value of the keyboard
controller just before the auxially port is probed.
It usually is 4D, 45, 47 or 65, depending on the keyboard device
driver.
.Pp
The second line shows the result of the keyboard controller's
test on the auxially port interface, with zero indicating
no error; note that some controllers report no error even if
the port does not exist in the system, however.
.Pp
The third to 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.
.Pp
The seventh line show the current hardware settings; it consists 
of three bytes:
.Bl -tag -width Byte_1
.It Byte 1
.Bl -tag -width bit_6
.It bit 6
0: stream mode (default after reset), 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.
.It bit 5
Set if the pointing device is currently enabled. Otherwise zero.
.It bit 4
0 - 1:1 scaling, 1 - 2:1 scaling.
.It bit 2
Left button status; set if pressed.
.It bit 1
Middle button status; set if pressed.
.It bit 0
Right button status; set if pressed.
.El
.It Byte 2
Resolution.
.Bl -tag -width 100
.It 0
25 pulse per inch (ppi)
.It 1
50 ppi
.It 2
100 ppi
.It 3
200 ppi
.El
.It Byte 3
The status report rate (reports/sec) at which the device will send 
movement report to the host computer.
.El
.Pp
Note that the pointing device will not be enabled until the 
.Nm
device is opened by the user programs.
.Pp
At debug level 2, much more detailed information is logged.
.Sh CAVEATS
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, because there is not a unique bit pattern to identify
the first byte with.
.Sh BUGS
The driver includes the code for the 
.Dv MOUSECREAD
command of
.Fn ioctl
function, which fills a 
.Fa mouseinfo
structure (see 
.Ao Pa machine/mouse.h Ac ).
However, it currently is not functioning properly, and may be removed
in the future.
.Sh SEE ALSO
.Xr syslog 3 ,
.Xr mse 4 ,
.Xr syslogd 8
.\" .Sh HISTORY
.\" .Sh AUTHOR