MOUSE(4) MidnightBSD Kernel Interfaces Manual MOUSE(4)
mouse — mouse and pointing device drivers
The mouse drivers mse(4), psm(4), ums(4) and sysmouse(4) provide user programs with movement and button state information of the mouse. Currently there are specific device drivers for bus, InPort, PS/2, and USB mice. The serial mouse is not directly supported by a dedicated driver, but it is accessible via the serial device driver or via moused(8) and sysmouse(4).
The user program simply opens a mouse device with a open(2) call and reads mouse data from the device via read(2). Movement and button states are usually encoded in fixed-length data packets. Some mouse devices may send data in variable length of packets. Actual protocol (data format) used by each driver differs widely.
The mouse drivers may have ‘‘non-blocking’’ attribute which will make the driver return immediately if mouse data is not available.
Mouse device drivers often offer several levels of operation. The current operation level can be examined and changed via ioctl(2) commands. The level zero is the lowest level at which the driver offers the basic service to user programs. Most drivers provide horizontal and vertical movement of the mouse and state of up to three buttons at this level. At the level one, if supported by the driver, mouse data is encoded in the standard format MOUSE_PROTO_SYSMOUSE as follows:
Left button status; cleared if pressed, otherwise set.
Middle button status; cleared if pressed, otherwise set. Always one, if the device does not have the middle button.
Right button status; cleared if pressed, otherwise set.
The first half of horizontal movement count in two’s complement; -128 through 127.
The first half of vertical movement count in two’s complement; -128 through 127.
The second half of the horizontal movement count in two’s complement; -128 through 127. To obtain the full horizontal movement count, add the byte 2 and 4.
The second half of the vertical movement count in two’s complement; -128 through 127. To obtain the full vertical movement count, add the byte 3 and 5.
The bit 7 is always zero. The lower 7 bits encode the first half of Z axis movement count in two’s complement; -64 through 63.
The bit 7 is always zero. The lower 7 bits encode the second half of the Z axis movement count in two’s complement; -64 through 63. To obtain the full Z axis movement count, add the byte 6 and 7.
The bit 7 is always zero. The bits 0 through 6 reflect the state of the buttons 4 through 10. If a button is pressed, the corresponding bit is cleared. Otherwise the bit is set.
The first 5 bytes of this format is compatible with the MouseSystems format. The additional 3 bytes have their MSBs always set to zero. Thus, if the user program can interpret the MouseSystems data format and tries to find the first byte of the format by detecting the bit pattern 10000xxxb, it will discard the additional bytes, thus, be able to decode x, y and states of 3 buttons correctly.
Device drivers may offer operation levels higher than one. Refer to manual pages of individual drivers for details.
The following ioctl(2) commands are defined for the mouse drivers. The degree of support varies from one driver to another. This section gives general description of the commands. Refer to manual pages of individual drivers for specific details.
MOUSE_SETLEVEL int *level
These commands manipulate the operation level of the mouse driver.
MOUSE_GETHWINFO mousehw_t *hw
Returns the hardware information of the attached device in the following Except for the iftype field, the device driver may not always fill the structure with correct values. Consult manual pages of individual drivers for details of support.
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 */
The buttons field holds the number of buttons detected by the driver. The driver may put an arbitrary value, such as two, in this field, if it cannot determine the exact number.
The iftype is the type of interface: MOUSE_IF_SERIAL, MOUSE_IF_BUS, MOUSE_IF_INPORT, MOUSE_IF_PS2, MOUSE_IF_USB, MOUSE_IF_SYSMOUSE or MOUSE_IF_UNKNOWN.
The type tells the device type: MOUSE_MOUSE, MOUSE_TRACKBALL, MOUSE_STICK, MOUSE_PAD, or MOUSE_UNKNOWN.
The model may be MOUSE_MODEL_GENERIC or one of MOUSE_MODEL_XXX constants.
The hwid is the ID value returned by the pointing device. It depend on the interface type; refer to the manual page of specific mouse drivers for possible values.
MOUSE_GETMODE mousemode_t *mode
The command reports the current operation parameters of the mouse driver.
int protocol; /* MOUSE_PROTO_XXX */
int rate; /* report rate (per sec) */
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; /* sync. bits */
The protocol field tells the format in which the device status is returned when the mouse data is read by the user program. It is one of MOUSE_PROTO_XXX constants.
The rate field is the status report rate (reports/sec) at which the device will send movement reports to the host computer. -1 if unknown or not applicable.
The resolution field holds a value specifying resolution of the pointing device. It is a positive value or one of MOUSE_RES_XXX constants.
The accelfactor field holds a value to control acceleration feature. It must be zero or greater. If it is zero, acceleration is disabled.
The packetsize field tells the length of the fixed-size data packet or the length of the fixed part of the variable-length packet. The size depends on the interface type, the device type and model, the protocol and the operation level of the driver.
The array syncmask holds a bit mask and pattern to detect the first byte of the data packet. syncmask is the bit mask to be ANDed with a byte. If the result is equal to syncmask, the byte is likely to be the first byte of the data packet. Note that this method of detecting the first byte 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
The command reads the raw data from the device.
int len; /* # of data in the buffer */
int buf; /* data buffer */
The calling process must fill the len field with the number of bytes to be read into the buffer. This command may not be supported by all drivers.
MOUSE_READSTATE mousedata_t *state
The command reads the raw state data from the device. It uses the same structure as above. This command may not be supported by all drivers.
MOUSE_GETSTATUS mousestatus_t *status
The command returns the current state of buttons and movement counts in the following structure.
int flags; /* state change flags */
int button; /* button status */
int obutton; /* previous button status */
int dx; /* x movement */
int dy; /* y movement */
int dz; /* z movement */
The button and obutton fields hold the current and the previous state of the mouse buttons. When a button is pressed, the corresponding bit is set. The mouse drivers may support up to 31 buttons with the bit 0 through 31. Few button bits are defined as MOUSE_BUTTON1DOWN through MOUSE_BUTTON8DOWN. The first three buttons correspond to left, middle and right buttons.
If the state of the button has changed since the last MOUSE_GETSTATUS call, the corresponding bit in the flags field will be set. If the mouse has moved since the last call, the MOUSE_POSCHANGED bit in the flags field will also be set.
The other fields hold movement counts since the last MOUSE_GETSTATUS call. The internal counters will be reset after every call to this command.
bus and InPort mouse device
PS/2 mouse device
virtual mouse device
USB mouse device
ioctl(2), mse(4), psm(4), sysmouse(4), ums(4), moused(8)
This manual page was written by Kazutaka Yokota 〈yokota@FreeBSD.org〉.
MidnightBSD 0.3 December 3, 1997 MidnightBSD 0.3