pcvt, vt -- VT220 virtual screen system console
device vt0
In /boot/device.hints:
hint.vt.0.at="isa"
Overview
The pcvt driver provides a virtual screen handling system. Probably most
important is an emulation of a wide range of DEC VT-220 functionality.
See Features for a detailed description.
The pcvt driver requires the keyboard driver atkbd to be also configured
in the kernel.
Features [Toc] [Back]
+o Almost full DEC VT220 functionality (moving towards VT320)
+o Completely independent virtual terminals for MDA/HGC/CGA/EGA and VGA
+o 25, 28, 35, 40, 43 or 50x80 screen resolution for each virtual screen
+o Fully remappable keyboard to support national keyboards
+o All VT220 character sets plus ISO Latin-1 and DEC technical supported
+o VT220 downloadable character set supported when run on EGA/VGA
+o VT220 user defined keys for each virtual terminal
+o Optional function key label support a la Hewlett-Packard terminals
+o Display function codes functionality
+o Support for MDA, CGA, EGA and VGA display adaptors
+o Support for 132 column operation on some VGA chipsets
+o X Window Support for XFree86 (requires XSERVER to be defined)
What it cannot:
+o No double wide/high characters
+o No softscroll
+o No inverse background
+o No VT220 printer output support
+o No VT52 support at all
+o No 8-bit controls
+o Only limited AT-keyboard (84 keys) support
Scrollback [Toc] [Back]
Each virtual pcvt virtual terminal has 8 pages of memory attached which
are used as a scrollback buffer. By using SHIFT-PageUp and
SHIFT-PageDown it is possible to scroll the screen back and forward.
Configuration [Toc] [Back]
The pcvt console driver is available for the Intel-based FreeBSD operating
system. It has been designed to be highly configurable in order to
satisfy everyone's needs. The preferred way for those configurations is
to provide appropriate options lines within the config file, possibly
overriding the built-in default values.
The following list gives a short overview of the available configuration
options. Refer to the file i386/isa/pcvt/pcvt_conf.h in the kernel
source tree for detailed documentation.
Note: the following conventions apply to all the Boolean options. If an
option is given with no value, a value of 1 (activated) is substituted.
If an option value is given as 0, this options is deactivated. Any other
value is substituted by 1, too. If an option is omitted, a built-in
default is assumed.
PCVT_NSCREENS
Defines the number of virtual screens.
Default: 8
PCVT_VT220KEYB
If activated, a keyboard layout resembling a DEC VT200 (TM) is
generated. If deactivated, a mixture between VT220 and HP is
used. See the files Keyboard.VT and Keyboard.HP in the pcvt documentation
directory for a full description.
Default: off
PCVT_SCREENSAVER
Enables the builtin screensaver feature.
Default: on
PCVT_PRETTYSCRNS
If enabled, a blinking-star screensaver is used. If disabled,
the screen is simply blanked (which might be useful for energysaving
monitors).
Default: on
PCVT_CTRL_ALT_DEL
If enabled, the key combination <Ctrl> <Alt> <Del> invokes a CPU
reset.
Default: off
PCVT_USEKBDSEC
Do NOT override a security lock for the keyboard.
Default: on
PCVT_24LINESDEF
If enabled, the 25-line modi (VT emulation with 25 lines, and HP
emulation with 28 lines) default to 24 lines only to provide a
better compatibility to the original DEV VT220 (TM). Thus it
should be possible to use the terminal information for those terminals
without further changes. Note that this is a startup
option; it is possible to toggle between the 24- and 25-lines'
display by the scon(1) utility.
Default: off
PCVT_META_ESC
If enabled, a sequence composed of <esc>, followed by the normal
key code is emitted if a key is pressed with the <Alt> key modifier.
If disabled, then normal key code with the value 0x80
added is sent.
Default: off
Note that there are further options available which are mainly used for
debugging purposes or as a workaround for hardware problems. They are
found in i386/isa/pcvt/pcvt_conf.h along with their documentation.
Internal Functions [Toc] [Back]
The functionality described below may be accessed via ioctl(2) system
calls with a file descriptor opened on a device node related to the pcvt
driver. To make use of them, a program should contain the following
line:
#include <machine/pcvt_ioctl.h>
Any parameter definitions cited below can be found in that file.
Keyboard related functions
Three functions are related to basic keyboard hardware:
KBDRESET reset keyboard, set defaults;
KBDGTPMAT get current typematic value, parameter is a
pointer to int where the values is stored to;
KBDSTPMAT set current typematic value, similar to above
command.
Symbolic values are available for the appropriate constants. To specify
the initial typematic delay time, they are KBD_TPD250 for 250 ms through
KBD_TPD1000 for 1000 ms, in steps of 250 ms. The typematic repeat rates
are KBD_TPM300, specifying 30.0 characters per second through KBD_TPM20
for 2.0 characters per second. The intermediate values are: 30.0, 26.7,
24.0, 21.8, 20.0, 18.5, 17.1, 16.0, 15.0, 13.3, 12.0, 10.9, 10.0, 9.2,
8.6, 8.0, 7.5, 6.7, 6.0, 5.5, 5.0, 4.6, 4.3, 4.0, 3.7, 3.3, 3.0, 2.7,
2.5, 2.3, 2.1, 2.0 characters per second.
KBDGREPSW get key repetition switch, and
KBDSREPSW set key repetition switch
again take a pointer to int as argument. They manipulate the drivers
internal keyboard repetition flag, possible values are: KBD_REPEATOFF or
KBD_REPEATON.
KBDGLEDS get LED state, and
KBDSLEDS set LED state manipulate the keyboard indicators,
but do not influence the drivers idea
of lock key state.
The int where the argument points to may have the values KBD_SCROLLLOCK,
KBD_NUMLOCK, KBD_CAPSLOCK, which may be used in any conjunction.
KBDGLOCK gets state of SCROLL,NUM,CAPS, and
KBDSLOCK sets state of SCROLL,NUM,CAPS + LEDs
should be used in a same manner to get/set the drivers internal LED
flags.
Keyboard remapping
One important feature of the pcvt driver is its ability to overload the
built in key definition.
KBDGCKEY get current key values,
KBDSCKEY set new key assignment values, and
KBDGOKEY get original key assignment values
arrange those functions. The take a pointer to a struct kbd_ovlkey as
argument as described below. In addition,
KBDRMKEY removes a key assignment, taking a pointer to
an int as argument which contains the
affected key number;
KBDDEFAULT removes all key assignments.
struct kbd_ovlkey /* complete definition of a key */
{
u_short keynum; /* the key itself */
u_short type; /* type of key, see below */
u_char subu; /* subtype, ignored on write */
char unshift[KBDMAXOVLKEYSIZE+1]; /* emitted string, unshifted */
u_char subs; /* subtype, ignored on write */
char shift[KBDMAXOVLKEYSIZE+1]; /* emitted string, shifted */
u_char subc; /* subtype, ignored on write */
char ctrl[KBDMAXOVLKEYSIZE+1]; /* emitted string, control */
u_char suba; /* subtype, ignored on write */
char altgr[KBDMAXOVLKEYSIZE+1]; /* emitted string, altgr */
};
The appropriate values for the type field are:
KBD_NONE no function, key is disabled,
KBD_SHIFT keyboard shift,
KBD_META alternate shift, sets bit8 to ASCII code,
KBD_NUM numeric shift, keypad numeric / application
mode,
KBD_CTL control code generation,
KBD_CAPS caps shift - swaps case of letter,
KBD_ASCII ASCII code generating key,
KBD_SCROLL stop output,
KBD_FUNC function key,
KBD_KP keypad keys,
KBD_BREAK ignored,
KBD_ALTGR AltGr translation feature,
KBD_SHFTLOCK shift lock,
KBD_CURSOR cursor keys, and
KBD_RETURN ``Return'' or ``Enter'' keys.
The subtype field contains one of the values
KBD_SUBT_STR key is bound to a string, or
KBD_SUBT_FNC key is bound to a function.
Downloadable character set interface
EGA and VGA video adaptors provide the capability of downloadable software
fonts. Since the `native character set' of any IBM-compatible PC
video board does not allow the full interpretation of DEC multinational
character set or ISO Latin-1 (ISO 8859-1), this might be very useful for
a U**X environment.
VGASETFONTATTR set font attr, and
VGAGETFONTATTR get font attr
are used to manipulate the drivers information about a downloaded font.
The take a pointer to a struct vgafontattr as argument:
struct vgafontattr {
int character_set; /* VGA character set */
int font_loaded; /* Mark font loaded or unloaded */
int screen_size; /* Character rows per screen */
int character_scanlines; /* Scanlines per character - 1 */
int screen_scanlines; /* Scanlines per screen - 1 byte */
};
Each character of each font is to be downloaded with
VGALOADCHAR load vga char,
taking a pointer to struct vgaloadchar as its argument:
struct vgaloadchar {
int character_set; /* VGA character set to load into */
int character; /* Character to load */
int character_scanlines; /* Scanlines per character */
u_char char_table[32]; /* VGA character shape table */
};
The field character_set takes the values CH_SET0, CH_SET1, CH_SET2,
CH_SET3 on EGA's or VGA's. Since VGA's might have up to eight simultaneously
loaded fonts, they can take CH_SET4, CH_SET5, CH_SET6, or CH_SET7,
too.
Note that there's a dependence between the font size and a possible
screen height (in character rows), depending on the video adaptor used:
Screen size (rows) on: EGA VGA
Font size
8 x 8 43 50
8 x 10 35 40
8 x 14 25 28
8 x 16 not 25
applicable
General screen manipulation commands
VGACURSOR sets cursor shape,
taking a pointer to the following structure as argument:
struct cursorshape {
int screen_no; /* screen number for which to set, */
/* or -1 to set on current active screen */
int start; /* top scanline, range 0... Character Height - 1 */
int end; /* end scanline, range 0... Character Height - 1 */
};
VGASETSCREEN set screen info, and
VGAGETSCREEN get screen info,
provide an interface to some general driver internal variables which
might modify the behaviour of the screens, or which might simply be used
to force the driver to switch to one certain screen. Their argument is a
pointer to the structure:
struct screeninfo {
int adaptor_type; /* type of video adaptor installed */
/* read only, ignored on write (yet!) */
int totalfonts; /* no of downloadable fonts */
/* read only, ignored on write */
int totalscreens; /* no of virtual screens */
/* read only, ignored on write */
int screen_no; /* screen number, this was got from */
/* on write, if -1, apply pure_vt_mode */
/* and/or screen_size to current screen*/
/* else to screen_no supplied */
int current_screen; /* screen number, which is displayed. */
/* on write, if -1, make this screen */
/* the current screen, else set current*/
/* displayed screen to parameter */
int pure_vt_mode; /* flag, pure VT mode or HP/VT mode */
/* on write, if -1, no change */
int screen_size; /* screen size */
/* on write, if -1, no change */
int force_24lines; /* force 24 lines if 25 lines VT mode */
/* or 28 lines HP mode to get pure */
/* VT220 screen size */
/* on write, if -1, no change */
int vga_family; /* if adaptor_type = VGA, this reflects*/
/* the chipset family after a read */
/* nothing happens on write ... */
int vga_type; /* if adaptor_type = VGA, this reflects*/
/* the chipset after a read */
/* nothing happens on write ... */
int vga_132; /* set to 1 if driver has support for */
/* 132 column operation for chipset */
/* currently ignored on write */
};
Its field pure_vt_mode may take the values M_HPVT for a mixed VTxxx and
HP Mode, with function key labels and a status line, or M_PUREVT for only
VTxxx sequences recognized, with no labels.
VGASETCOLMS sets the number of columns for the current
screen,
its parameter is a pointer to an integer containing either a value of 80,
or a value of 132. Note that setting the number of columns to 132 is
only supported on some VGA adaptors. Any unsupported numbers cause the
ioctl to fail with errno (see intro(2)) being set to EINVAL.
VGA color palette interface
Only on VGA adaptors, there's a color palette register at the output. It
is responsible for the red, green and blue output voltage provided for
each of the 256 internal color codes, each lying in the range of 0
through 63 (with 63 representing the brightest value for a base color).
Thus, these adaptors map each color code to a color of a ``palette'' out
of 262144 colors. The commands
VGAREADPEL read VGA palette entry, and
VGAWRITEPEL write VGA palette entry
establish an interface to these palette registers. Their argument is a
pointer to:
struct vgapel {
unsigned idx; /* index into palette, 0 .. 255 valid */
unsigned r, g, b; /* RGB values, masked by VGA_PMASK (63) */
};
Driver identification
VGAPCVTID returns information if the current compiled
in driver is pcvt and it's major and minor
revision numbers. the call is taking a
pointer to the following structure as argument:
struct pcvtid {
#define PCVTIDNAMELN 16 /* driver id - string length */
char name[PCVTIDNAMELN]; /* driver name, == PCVTIDSTR */
#define PCVTIDNAME "pcvt" /* driver id - string */
int rmajor; /* revision number, major */
#define PCVTIDMAJOR 3
int rminor; /* revision number, minor */
#define PCVTIDMINOR 00
};
VGAPCVTINFO returns information if the current compiled
in driver is pcvt and it's compile time
options. the call is taking a pointer to the
following structure as argument:
struct pcvtinfo {
u_int opsys; /* PCVT_xxx(x)BSD */
#define CONF_UNKNOWNOPSYS 0
#define CONF_386BSD 1 /* unsupported !!! */
#define CONF_NETBSD 2
#define CONF_FREEBSD 3
u_int opsysrel; /* Release for NetBSD/FreeBSD */
u_int nscreens; /* PCVT_NSCREENS */
u_int scanset; /* PCVT_SCANSET */
u_int updatefast; /* PCVT_UPDATEFAST */
u_int updateslow; /* PCVT_UPDATESLOW */
u_int sysbeepf; /* PCVT_SYSBEEPF */
u_int pcburst; /* PCVT_PCBURST */
u_int kbd_fifo_sz; /* PCVT_KBD_FIFO_SZ */
/* config booleans */
u_long compile_opts; /* PCVT_xxxxxxxxxxxxxxx */
};
Screen saver
Depending on the configuration of a pcvt driver, their might be a simple
screen saver available. It is controlled by the command
VGASCREENSAVER set timeout for screen saver in seconds; 0
turns it off,
taking a pointer to an integer as argument. Despite of its command name,
this is available on any kind of adaptor if configured in by the
config(8) option ``PCVT_SCREENSAVER''
Compatibility commands for USL-style VT's
pcvt supports a subset of the USL-style commands used to control the virtual
terminal interface. This feature is mainly intended to allow
XFree86 to switch between virtual screens even when running an X server.
They are ugly with respect to the implied semantics (i.e., they break
Berkeley semantics). See the file i386/include/pcvt_ioctl.h for their
documentation.
/usr/include/machine/pcvt_ioctl.h Definitions for ioctl(2) function
calls
/dev/ttyv?
/dev/console Device nodes to access the pcvt driver
i386/isa/pcvt/pcvt_conf.h (relative to the kernel source tree)
Documents the various compile-time
options to tailor pcvt.
The pcvt driver has been developed for and contributed to 386BSD 0.1.
Since then pcvt has become a standard part of FreeBSD, NetBSD and
OpenBSD. Since FreeBSD 5.0, pcvt is FreeBSD specific with support for
NetBSD and OpenBSD removed to ease further maintenance.
Written by Hellmuth Michaelis <[email protected]> with much help from Brian
Dunford-Shore <[email protected]> and Jorg Wunsch
<[email protected]>.
This driver is based on several people's previous work, notably the historic
pccons(4) implementation by William Jolitz
<[email protected]> and Don Ahn, and the keyboard mapping code from
Holger Veit <[email protected]>.
cursor(1), loadfont(1), scon(1), intro(2), ioctl(2), atkbd(4),
keyboard(4), config(8), ispcvt(8)
At least one left.
FreeBSD 5.2.1 March 26, 2000 FreeBSD 5.2.1 [ Back ] |
