PSM (4) | Special files and drivers | Unix Manual Pages

PSM (4) | Special files and drivers | Unix Manual Pages | :man▋

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 proprietary data format. Therefore, the user program is expected to have intimate knowledge about the format from a particular device when operating 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 format of the data packet.

Acceleration

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 immediately’’. 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.

DRIVER CONFIGURATION

Kernel Configuration Options

There are following kernel configuration options to control the psm driver. They may be set in the kernel configuration file (see config(8)).

KBD_RESETDELAY=X, KBD_MAXWAIT=Y
	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.
PSM_DEBUG=N, KBDIO_DEBUG=N
	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 disables 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 helps.
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 .Fx 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.
bit 12 IGNOREPORTERROR
	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.
bit 14 INITAFTERSUSPEND
	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.

LOADER TUNABLES

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

IOCTLS

There are a few ioctl(2) commands for mouse drivers. These commands and related structures and constants are defined in
.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 manufacturer 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 include:
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 driver. 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 feature (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 device.

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).

FILES

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

EXAMPLES

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 /boot/device.hints.

hint.atkbdc.0.at= "isa"

hint.atkbdc.0.port= "0x060"

hint.psm.0.at= "atkbdc"

hint.psm.0.irq= "12"

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

hint.psm.0.flags= "0x2000"

you will add the optional code to stimulate the pointing device after the ‘resume’ event.

hint.psm.0.flags= "0x24"

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

DIAGNOSTICS

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 controller 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 system, 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. Otherwise zero.
bit 4	0 - 1:1 scaling, 1 - 2:1 scaling. 1:1 scaling is the default.
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 another.

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.

CAVEATS

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 tapping 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. However, 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.

AUTHORS

BUGS

Created by Blin Media, 2008-2013

NAME

CONTENTS

SYNOPSIS

DESCRIPTION

Device Resolution

Report Rate

Operation Levels