.\"	$Id$
.\"
.Dd January 13, 1997
.Dt PSM 4 i386
.Os FreeBSD
.Sh NAME
.Nm psm
.Nd
PS/2 mouse style pointing device driver
.Sh SYNOPSIS
.Cd "options PSM_CHECKSYNC"
.\".Cd "options PSM_EMULATION"
.Cd "options" \&"PSM_ACCEL=N\&"
.Cd "options" \&"KBD_RESETDELAY=N\&"
.Cd "options" \&"KBD_MAXWAIT=N\&"
.Cd "options" \&"PSM_DEBUG=N\&"
.Cd "options" \&"KBDIO_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.

.Em port \&"IO_KBD\&"
and
.Em conflicts
are required, 
as the PS/2 mouse port is located
at the auxiliary port of the keyboard controller, thus, the 
.Nm
driver has to share the same I/O ports with the keyboard driver.
Note also that there is currently no provision of changing the 
.Em 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 -compact
.It Byte 1 
.Bl -tag -width bit_7 -compact
.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
The ALPS GlidePoint clears this bit when the user `taps' the surface of 
the pad, otherwise the bit is set.
Most, if not all, other devices always sets this bit.
.It bit 2
Middle button status; set if pressed. For devices without the middle
button, this bit seems to be always zero.
.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; 
-256 through 255.
Note that the sign bit is in the first byte.
.It Byte 3
Vertical movement count in two's compliment; 
-256 through 255.
Note that the sign bit is in the first byte.
.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.
See
.Sx FILES
for device node names.
.Sh KERNEL CONFIGURATION
There are following options to control the
.Nm
driver.
.Bl -tag -width MOUSE
.It Em PSM_CHECKSYNC
If this option is defined, the driver tries to detect the first byte of 
the three-byte data packet, by checking the bit pattern of that byte. 
This may be useful if you often experience wierd mouse movement
cased by unsynchronization between the application program and the mouse.
However, the
.Em PSM_CHECKSYNC
code may not always work; some systems, mostly notebooks, set the bit 
pattern differently from the others.
Note also that the `tapping' feature of the ALPS GlidePoint will be
lost when this option is used.
.\".It Em PSM_EMULATION
.\"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 .
.\"To enable the emulation feature, define this option.
.It Em PSM_ACCEL=N
The
.Nm
driver can somewhat `accelerate' the movement of the pointing device.
That is, the faster you move the device, the further the pointer 
travels on the screen. This option controls the amount of acceleration.
The smaller
.Fa N
is, more sensitive the movement becomes. 
The minimum value allowed, thus the value for the most sensitive setting, 
is 1. Setting this option to zero will completely disables the
acceleration effect. The default value is 0 (acceleration disabled).
The acceleration effect can also be controlled via the
.Fn ioctl
command
.Dv MOUSE_SETMODE .
.It Em KBD_RESETDELAY=X, KBD_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, KBDIO_DEBUG=N
Sets the debug level to 
.Fa N .
The default debug level is zero. See
.Sx DIAGNOSTICS
for debug logging.
.El
.Sh IOCTL
There are only few ioctls for the
.Nm
driver. These are defined in
.Ao Pa machine/mouse.h Ac .
.Bl -tag -width MOUSE
.It Dv MOUSEIOCREAD
The 
.Dv MOUSEIOCREAD
command did NOT work before and does NOT work now. It is obsolete. 
Use the
.Dv MOUSE_GETSTATE
command instead.
.It Dv MOUSE_GETSTATE 
The command returns the current mouse state in the following structure
and remove the state information from the internal queue.
.Bd -literal
typedef struct mousestatus {
    int button;     /* button status */
    int obutton;    /* previous button status */
    int dx;         /* x movement */
    int dy;         /* y movement */
} mousestatus_t;
.Ed
.Pp
The
.Dv button
and the
.Dv obutton
fields hold the current and the previous state of the mouse buttons.
When a button is pressed, the corresponding bit is set.
These bits are defined as 
.Dv MOUSE_BUTTON1DOWN
through 
.Dv MOUSE_BUTTON8DOWN .
The first three buttons are left, middle and right buttons.
.Pp
Note that this command and
.Fn read
operation on the 
.Nm
driver uses the same internal queue. Therefore, interleaving the
.Dv MOUSE_GETSTATE
command 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. 
Known IDs include:
.Bl -tag -width 0__ -compact
.It Em 0
Mouse (Microsoft, Logitech and many other manufacturers)
.It Em 2
Microsoft Ballpoint mouse
.El
.It Dv MOUSE_GETMODE, MOUSE_SETMODE
The commands get and set the 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;  /* 1:low, 2:medium low, 3:medium high
                      * 4:high, 0: default, -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 read by user
programs as is. 
No other value is allowed at the moment.
.\"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.
.\"Note that the protocol cannot be set to anything other than
.\".Dv MOUSE_PROTO_PS2
.\"unless the
.\".Em PSM_EMULATION
.\"option is specified in the kernel configuration file.
.Pp
The
.Dv rate
is the status report rate (reports/sec) at which the device will send 
movement report to the host computer.
.Pp
The
.Dv resolution
of the pointing device must be zero through four. The higher the value
is, the finer resolution the mouse will select. Zero selects the
default resolution. 
.Pp
The
.Dv accelfactor
holds a value to control acceleration feature (see description on
.Em PSM_ACCEL
above). It must be zero or greater.
If it is zero, acceleration is disabled.
.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
.Ed
.Pp
where
.Fa X
the device ID code returned by the found pointing device.
See
.Dv MOUSE_GETINFO
for known IDs.
.Pp
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 
.Xr syslogd 8 . )
.Bd -literal -offset indent
psm0: current command byte:xxxx
kbdio: new command byte:yyyy (set_controller...)
kbdio: TEST_AUX_PORT status:0000
kbdio: RESET_AUX return code:00fa
kbdio: RESET_AUX status:00aa
kbdio: RESET_AUX ID:0000
psm0: status after reset 00 02 64
psm: device ID: X
psm: status xx yy zz (get_mouse_buttons)
psm0: status 00 02 64
kbdio: new command byte:zzzz (set_controller...)
psm0 at 0x60-0x64 irq 12 on motherboard
psm0: device ID X, N buttons
.Ed
.Pp
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 controller upon power-up.
.Pp
The third 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 system, however.
.Pp
The forth to sixth 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 tenth line shows the current hardware settings; it consists 
of three bytes:
.Pp
.Bl -tag -width Byte_1 -compact
.It Byte 1
.Bl -tag -width bit_6 -compact
.It bit 7
Reserved.
.It 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.
.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 3
Reserved.
.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
.Bl -tag -width bit_6_0 -compact
.It bit 7
Reserved.
.It bit 6-0
Resolution code: zero through three. The higher the number is, 
the finer resolution the device has. Actual resolution for
the resolution code varies from one device to another.
The typical values are:
.Bl -tag -width 100 -compact
.It 0
25 pulse per inch (ppi)
.It 1
50 ppi
.It 2
100 ppi
.It 3
200 ppi
.El
.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
driver is opened by the user programs.
.Pp
The last line shows the device ID code and the number of detected
buttons. 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 2, much more detailed information is logged.
.Sh FILES
.Bl -tag -width /dev/npsm0 -compact
.It Pa /dev/psm0
`non-blocking' device node in the system without
.Em devfs ,
`blocking' under
.Em devfs .
.It Pa /dev/npsm0
`non-blocking' device node under
.Em devfs .
.El
.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. However, if you are using the \fIXFree86\fP 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
.Xr moused 1 .
If you have specified the
.Em PSM_CHECKSYNC
option, clicking any button without moving the mouse may also work.
.Sh BUGS
The 
.Fn ioctl 
command
.Dv MOUSEIOCREAD
(see
.Sx IOCTL
above) was never functional and will not be. The command name
still remains for compatibility reasons but may be removed in the future.
.Sh SEE ALSO
.Xr moused 1 ,
.Xr syslog 3 ,
.Xr mse 4 ,
.Xr syslogd 8
.\" .Sh HISTORY
.\" .Sh AUTHOR