ps2.7 (2010 09)

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ps2(7) ps2(7)

NAME

ps2, ps2kbd, ps2mouse - PS/2 keyboard/mouse device driver and ﬁles

SYNOPSIS

#include <sys/ps2io.h>

DESCRIPTION

The ps2 driver allows the use of IBM Personal System/2 (PS/2) compatible keyboards and mouse devices

on Hewlett-Packard workstations equipped with PS/2 interface hardware.

On systems with a single interface, PS/2 device ﬁle names use the following format:

/dev/ps2_n

where n represents the interface port number, ranging from 0 to 15. For example, the device ﬁle

/dev/ps2_1 is used to access port one.

On systems with more than one interface, PS/2 device ﬁle names use the following format:

/dev/ps2_m.n

where m represents the interface number, and n represents the port number. For example, the device ﬁle

/dev/ps2_1.2 is used to access port two on interface one.

At boot time, the

ps2 driver scans all interface ports from port zero to the maximum number of ports

implemented and attempts to identify attached PS/2 devices. The /dev/ps2mouse

device ﬁle accesses

the ﬁrst mouse detected by

ps2. The /dev/ps2kbd device ﬁle accesses the ﬁrst keyboard detected by

ps2.

PS/2 devices are classiﬁed as "slow" devices. This means that system calls to

ps2 can be interrupted by

caught signals (see signal (5)).

The mouse may be placed in one of two output modes. In stream mode, the mouse generates a three-byte

report packet in response to mouse movement and/or button presses. These reports can be obtained with

the

read() system call (see read (2)). In prompt mode, an ioctl() request polls the mouse, returning

a three-byte report packet in a buffer whose address is passed as an argument to the

ioctl() call.

PS/2 keyboards return keycodes that represent key-press and key-release events. Use the Internal Ter-

minal Emulator (ITE) to read ASCII characters from PS/2 keyboards. The ASCII terminal interface used

by the ITE is described in termio (7).

The

ps2 driver provides a low-level programming interface to PS/2 keyboards and mice. To access these

devices in a hardware independent way, use the X Window programming environment.

System Calls

The

open() system call gives exclusive access to the speciﬁed PS/2 device (see open(2)). If a port is

open, all

open() calls made on that port will fail with errno set to [EBUSY] (see errno(2)).

If an open is attempted on a nonexistent port, the

open() call fails with errno set to [ENXIO].

If no keyboard is detected at system boot and an

open() is attempted on /dev/ps2kbd, or if no mouse

is detected at system boot and an open() is attempted on /dev/ps2mouse, the open() call fails with

errno set to [ENXIO].

Attempts to open an existing

ps2 port with no device connected will succeed.

Upon a successful open, any previously queued input from the device is discarded. Keystrokes are routed

to the ITE by default. While a keyboard is open, ITE does not receive keystrokes from that keyboard;

until the keyboard device is closed, it has exclusive access to keyboard input.

The ﬁle status ﬂags

O_NDELAY and O_NONBLOCK can be set to enable nonblocking reads (see open(2)).

read() returns bytes from a PS/2 device. HP-UX maintains a 512-byte buffer for each port. When this

buffer is full, additional bytes received from the device are discarded.

If enough buffered data is available to satisfy the entire number of bytes requested, the

read() call com-

pletes successfully, having read all of the data requested and returning the number of bytes read.

If there is not enough buffered data available to satisfy the entire request, but at least one byte is avail-

able, the

read() call completes successfully, having read all available data and returning the number of

bytes actually read.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (8 pages)

PAGE 1
ps2(7) ps2(7) NAME ps2, ps2kbd, ps2mouse - PS/2 keyboard/mouse device driver and files SYNOPSIS #include DESCRIPTION The ps2 driver allows the use of IBM Personal System/2 (PS/2) compatible keyboards and mouse devices on Hewlett-Packard workstations equipped with PS/2 interface hardware. On systems with a single interface, PS/2 device file names use the following format: /dev/ps2_n where n represents the interface port number, ranging from 0 to 15.
PAGE 2
ps2(7) ps2(7) If both file status flags O_NDELAY and O_NONBLOCK are clear and no data is available, the read() call blocks until data becomes available or a signal is received. If the file status flag O_NDELAY is set and no data is available, the read() call returns zero instead of blocking. If the file status flag O_NONBLOCK is set and no data is available, the read() call returns -1 with errno set to [EAGAIN] (see errno (2)). The write() system call is not supported by ps2.
PAGE 3
ps2(7) PS2_ENABLE ps2(7) Enable a PS/2 device Transmissions from the device are enabled. This request does not use arg. PS2_IDENT Identify a PS/2 device. A value identifying the type of device is returned in the 4-byte buffer addressed by arg. The keyboard returns two bytes (arg[0]=0xAB and arg[1]=0x83). The mouse returns one byte (arg[0]=0x00). PS2_SETDEFAULT Set the device to its default (power-up) state. The device is returned to its default internal state. This request does not use arg.
PAGE 4
ps2(7) PS2_KEY_MAKE ps2(7) Set make-only behavior for an individual key. The key code from scancode set 3 for the individual key is passed as the first byte in the character buffer addressed by arg. This request can be made when the keyboard is using any scancode set; however, it affects only the operation of scancode set 3. Because keyboards might be left in a disabled state after this request, the PS2_ENABLE request should be performed after PS2_KEY_MAKE.
PAGE 5
ps2(7) ps2(7) ioctl() request. The arg parameter is not used. PS2_REPORT Obtain a prompt mode mouse report. This request polls the mouse, obtaining a three-byte report returned in the character buffer addressed by the arg parameter.
PAGE 6
ps2(7) ps2(7) RES_1 RES_2 RES_3 RES_4 PS2_2TO1_SCALING 1 count/mm 1 count/mm 2 count/mm 3 count/mm 4 count/mm 6 count/mm 8 count/mm 12 count/mm Set mouse scaling at 2 to 1. The X and Y coordinate values returned in stream-mode reports are doubled, except for absolute values less than six, which are converted to new values in a nonlinear fashion.
PAGE 7
ps2(7) ps2(7) printf("Indicators off\n"); /* use scancode set 3 */ kbdbuf[0] = SCANCODE_3; if( ioctl( fildes, PS2_SCANCODE, &kbdbuf) < 0){ perror("ioctl PS2_SCANCODE failed"); exit(1); } /* identify our scancode set */ kbdbuf[0] = GET_SCANCODE; if( ioctl( fildes, PS2_SCANCODE, &kbdbuf) < 0){ perror("ioctl PS2_SCANCODE failed"); exit(1); } printf("Keyboard reports it is using scancode set %d\n", (unsigned int) kbdbuf[0]); /* now, loop forever while printing keycodes */ while( 1){ read( fildes, &inchar, 1);
PAGE 8
ps2(7) ps2(7) if (read(fildes, &buf[0], perror("Read of report return 1; } if (read(fildes, &buf[1], perror("Read of report return 1; } if (read(fildes, &buf[3], perror("Read of report return 1; } printf("mouse: 0x%02x, %d 1) != 1){ byte 1 failed"); 1) != 1){ byte 2 failed"); 1) != 1){ byte 3 failed"); %d\n", buf[0], buf[1], buf[2]); } AUTHOR ps2 was developed by the Hewlett-Packard Company. PS/2 and Personal System/2 are registered trademarks of International Business Machines, Incorporated, in the U.