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VT(4)			    Kernel Interfaces Manual			 VT(4)

NAME
       vt -- virtual terminal system video console driver

SYNOPSIS
       options TERMINAL_KERN_ATTR=<attribute>
       options TERMINAL_NORM_ATTR=<attribute>
       options VT_MAXWINDOWS=<N>
       options VT_ALT_TO_ESC_HACK=1
       options VT_TWOBUTTON_MOUSE
       options VT_FB_MAX_WIDTH=<X>
       options VT_FB_MAX_HEIGHT=<Y>
       options SC_NO_CUTPASTE
       device vt

       In loader.conf(5):
       hw.vga.textmode=1
       hw.vga.acpi_ignore_no_vga=1
       kern.vty=vt
       kern.vt.color.<colornum>.rgb=<colorspec>
       kern.vt.fb.default_mode=<X>x<Y>
       kern.vt.fb.modes.<connector>=<X>x<Y>
       kern.vt.slow_down=<delay>
       screen.font=<X>x<Y>

       In loader.conf(5) or sysctl.conf(5):
       kern.consmute=1
       kern.vt.kbd_halt=1
       kern.vt.kbd_poweroff=1
       kern.vt.kbd_reboot=1
       kern.vt.kbd_debug=1
       kern.vt.kbd_panic=0
       kern.vt.enable_altgr=0
       kern.vt.enable_bell=1

DESCRIPTION
       The  vt	device	provides  multiple virtual terminals with an extensive
       feature set:

	     Unicode UTF-8 text	with double-width characters.

	     Large font	maps in	graphics mode,	including  support  for	 Asian
	     character sets.

	     Graphics-mode consoles.

	     Integration  with	KMS  (Kernel  Mode  Setting) video drivers for
	     switching between the X Window System and virtual terminals.

   Virtual Terminals
       Multiple	virtual	terminals are provided on a single  computer.	Up  to
       sixteen virtual terminals can be	defined.  A single virtual terminal is
       connected  to  the screen and keyboard at a time.  Key combinations are
       used to select a	virtual	terminal.  Alt-F1 through  Alt-F12  correspond
       to  the	first  twelve  virtual terminals.  If more than	twelve virtual
       terminals are created, Shift-Alt-F1 through Shift-Alt-F4	 are  used  to
       switch to the additional	terminals.

   Copying and Pasting Text with a Mouse
       Copying	and  pasting  text  from the screen with a mouse is supported.
       Press and hold down mouse button	1, usually the left button, while mov-
       ing the mouse to	select text.  Selected text is	highlighted  with  re-
       versed foreground and background	colors.	 To select more	text after re-
       leasing mouse button 1, press mouse button 3, usually the right button.
       To paste	text that has been selected, press mouse button	2, usually the
       middle  button.	 The  text  is entered as if it	were typed at the key-
       board.  The VT_TWOBUTTON_MOUSE kernel option can	be used	with mice that
       only have two buttons.  Setting this option makes the second mouse but-
       ton into	the paste button.  See moused(8) for more information.

   Scrolling Back
       Output that has scrolled	off the	screen can be reviewed by pressing the
       Scroll Lock key,	then scrolling up and down with	the arrow  keys.   The
       Page  Up	 and Page Down keys scroll up or down a	full screen at a time.
       The Home	and End	keys jump to the beginning or end  of  the  scrollback
       buffer.	 When  finished	 reviewing, press the Scroll Lock key again to
       return to normal	use.  Some laptop keyboards lack a  Scroll  Lock  key,
       and  use	 a  special  function  key sequence (such as Fn	+ K) to	access
       Scroll Lock.

DRIVER CONFIGURATION
   Kernel Configuration	Options
       These kernel options control the	vt driver.

       TERMINAL_NORM_ATTR=<attribute>

       TERMINAL_KERN_ATTR=<attribute>
		These options change the default colors	used  for  normal  and
		kernel	  text.	    Available	 colors	   are	  defined   in
		<sys/terminal.h>.  See "EXAMPLES" below.

       VT_MAXWINDOWS=<N>
		Set the	number of virtual terminals to be created to  N.   The
		value defaults to 12.

       VT_ALT_TO_ESC_HACK=1
		When the Alt key is held down while pressing another key, send
		an ESC sequence	instead	of the Alt key.

       VT_TWOBUTTON_MOUSE
		If  defined,  swap the functions of mouse buttons 2 and	3.  In
		effect,	this makes  the	 right-hand  mouse  button  perform  a
		paste.	These options are checked in the order shown.

       SC_NO_CUTPASTE
		Disable	mouse support.

       VT_FB_MAX_WIDTH=<X>
		Set the	maximum	width to X.

       VT_FB_MAX_HEIGHT=<Y>
		Set the	maximum	height to Y.

BACKWARDS COMPATIBILITY
       Several	options	 are provided for compatibility	with the previous con-
       sole device, sc(4).  These options will be removed in a future  FreeBSD
       version.

	     vt	Option Name	   sc Option Name
	     TERMINAL_KERN_ATTR	   SC_KERNEL_CONS_ATTR
	     TERMINAL_NORM_ATTR	   SC_NORM_ATTR
	     VT_TWOBUTTON_MOUSE	   SC_TWOBUTTON_MOUSE
	     VT_MAXWINDOWS	   MAXCONS
	     none		   SC_NO_CUTPASTE

START-UP OPERATION WITH	X86 BIOS SYSTEMS
       The  computer BIOS starts in text mode, and the FreeBSD loader(8) runs,
       loading the kernel.  If hw.vga.textmode is set, the system  remains  in
       text mode.  Otherwise, vt switches to 640x480x16	VGA mode using vt_vga.
       If  a  KMS (Kernel Mode Setting)	video driver is	available, the display
       is switched to high resolution and the KMS driver takes over.   When  a
       KMS driver is not available, vt_vga remains active.

LOADER TUNABLES
       These   settings	  can  be  entered  at	the  loader(8)	prompt	or  in
       loader.conf(5).

       hw.vga.textmode
	       Set to 1	to use virtual	terminals  in  text  mode  instead  of
	       graphics	mode.  Features	that require graphics mode, like load-
	       able fonts, will	be disabled.

	       If  a  KMS driver is loaded the console will switch to (and re-
	       main in)	graphics mode.

       hw.vga.acpi_ignore_no_vga
	       Set to 1	to force the usage of the  VGA	driver	regardless  of
	       whether	ACPI  IAPC_BOOT_ARCH  signals  no VGA support.	Can be
	       used to workaround firmware bugs	in the ACPI tables.   Note  no
	       VGA  support  is	 only  acknowledged  when running virtualized.
	       There is	too many broken	firmware that wrongly reports  no  VGA
	       support on physical hardware.

       kern.vty
	       Set this	value to `vt' or `sc' to choose	a specific system con-
	       sole,  overriding the default.  The GENERIC kernel uses vt when
	       this value is not set.  Note that `sc' is not  compatible  with
	       UEFI(8) boot.

       kern.vt.color.colornum.rgb
	       Set  this  value	 to  override  default palette entry for color
	       colornum	which should be	in a range from	 0  to	15  inclusive.
	       The  value  should  be either a comma-separated triplet of red,
	       green, and blue values in a range from 0	to  255	 or  HTML-like
	       hex triplet.  See "EXAMPLES" below.

	       Note:  The vt VGA hardware driver does not support palette con-
	       figuration.

       kern.vt.fb.default_mode
	       Set this	value to a graphic mode	to override the	default	picked
	       by the vt backend.  The mode is applied to all  output  connec-
	       tors.   This  is	 currently only	supported by the vt_fb backend
	       when it is paired with a	KMS video driver.

       kern.vt.fb.modes.<connector_name>
	       Set this	value to a graphic mode	to override the	default	picked
	       by the vt backend.  This	mode is	applied	to the output  connec-
	       tor    connector_name	only.	  It   has   precedence	  over
	       kern.vt.fb.default_mode.	  The  names  of  available  connector
	       names  can  be  found in	dmesg(8) after loading the KMS driver.
	       It will contain a list of connectors and	their associated  tun-
	       ables.	This  is currently only	supported by the vt_fb backend
	       when it is paired with a	KMS video driver.

       kern.vt.slow_down
	       When debugging the kernel on modern laptops, the	screen is  of-
	       ten  the	 only available	console, and relevant information will
	       scroll out of view before it can	be captured by eye or camera.

	       Setting kern.vt.slow_down to a non-zero number will  make  con-
	       sole output synchronous (ie: not	dependent on timers and	inter-
	       rupts) and slow it down in proportion to	the number.

       screen.font
	       Set  this  value	 to the	base name of the desired font file lo-
	       cated in	/boot/fonts.  Fonts can	 be  converted	for  use  with
	       vtfontcvt(8).

KEYBOARD SYSCTL	TUNABLES
       These settings control whether certain special key combinations are en-
       abled  or  ignored.  The	specific key combinations can be configured by
       using a keymap(5) file.

       These  settings	can  be	 entered  at  the  loader(8)  prompt   or   in
       loader.conf(5)  and  can	 also be changed at runtime with the sysctl(8)
       command.

       kern.vt.enable_altgr
	       Enable AltGr key	(do not	assume right Alt key as	Alt).

       kern.vt.kbd_halt
	       Enable halt keyboard combination.

       kern.vt.kbd_poweroff
	       Enable power off	key combination.

       kern.vt.kbd_reboot
	       Enable reboot key combination, usually Ctrl+Alt+Del.

       kern.vt.kbd_debug
	       Enable debug request key	combination, usually Ctrl+Alt+Esc.

       kern.vt.kbd_panic
	       Enable panic key	combination.

OTHER SYSCTL TUNABLES
       These  settings	can  be	 entered  at  the  loader(8)  prompt,  set  in
       loader.conf(5), or changed at runtime with sysctl(8).

       kern.consmute
	       Disable printing	kernel messages	to the system console.

       kern.vt.enable_bell
	       Enable the terminal bell.

FILES
       /dev/console
       /dev/consolectl
       /dev/ttyv*		    virtual terminals
       /etc/ttys		    terminal initialization information
       /usr/share/vt/fonts/*.fnt    console fonts
       /usr/share/vt/keymaps/*.kbd  keyboard layouts

DEVCTL MESSAGES
       System	 Subsystem    Type    Description
       VT	 BELL	      RING    Notification  that  the console bell has
						     rung.

       Variable	      Meaning
       duration_ms    Length of	 time  the  bell  was  requested  to  ring  in
				 milliseconds.
       enabled	      true  or	false  indicating  whether or not the bell was
				 administratively enabled when rung.
       hushed	      true or false indicating whether or  not	the  bell  was
				 quieted by the	user when rung.
       hz	      Tone that	was requested in Hz.

EXAMPLES
       This  example  changes  the  default color of normal text to green on a
       black background, or black on a green background	when  reversed.	  Note
       that  white space cannot	be used	inside the attribute string because of
       the current implementation of config(8).

	     options TERMINAL_NORM_ATTR=(FG_GREEN|BG_BLACK)

       This line changes the default color of kernel messages to be bright red
       on a black background, or black on a bright  red	 background  when  re-
       versed.

	     options TERMINAL_KERN_ATTR=(FG_LIGHTRED|BG_BLACK)

       To set a	1024x768 mode on all output connectors,	put the	following line
       in /boot/loader.conf:

	     kern.vt.fb.default_mode="1024x768"

       To  set	a  800x600  only on a laptop builtin screen, use the following
       line instead:

	     kern.vt.fb.modes.LVDS-1="800x600"

       The connector name was found in dmesg(8):

	     info: [drm] Connector LVDS-1: get mode from tunables:
	     info: [drm] - kern.vt.fb.modes.LVDS-1
	     info: [drm] - kern.vt.fb.default_mode

       To set black and	white colors of	console	palette

	     kern.vt.color.0.rgb="10,10,10"
	     kern.vt.color.15.rgb="#f0f0f0"

       Load the	8x16 font in  loader.conf(5)  from  /boot/fonts/*.fnt[.gz]  at
       boot:

	     screen.font="8x16"

SEE ALSO
       kbdcontrol(1), login(1),	vidcontrol(1), atkbd(4), atkbdc(4), kbdmux(4),
       keyboard(4),  screen(4),	 splash(4),  syscons(4),  ukbd(4),  kbdmap(5),
       loader.conf(5), rc.conf(5), ttys(5), config(8),	getty(8),  kldload(8),
       moused(8), vtfontcvt(8)

HISTORY
       The vt driver first appeared in FreeBSD 9.3.

AUTHORS
       The  vt device driver was developed by Ed Schouten <ed@FreeBSD.org>, Ed
       Maste <emaste@FreeBSD.org>, and	Aleksandr  Rybalko  <ray@FreeBSD.org>,
       with  sponsorship provided by the FreeBSD Foundation.  This manual page
       was written by Warren Block <wblock@FreeBSD.org>.

CAVEATS
       Paste buffer size is limited by the system value	{MAX_INPUT}, the  num-
       ber  of	bytes  that can	be stored in the terminal input	queue, usually
       1024 bytes (see termios(4)).

FreeBSD	16.0-CURRENT		 July 7, 2024				 VT(4)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=vt&sektion=4&manpath=FreeBSD+16.0-CURRENT>

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