Update vt(4) for UEFI defaults and special keys

vt(4) is the default console for UEFI boot [1], and the bitmapped
kern.vt.spclkeys sysctl has been replaced with individual kern.vt.kbd_*
enable sysctls.

PR:		193710
Submitted by:	wblock [1]
Reviewed by:	wblock
MFC after:	3 days
Relnotes:	Yes
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D953

1 files changed, 42 insertions, 23 deletions

diff --git a/share/man/man4/vt.4 b/share/man/man4/vt.4
index 889c75c..9929b2d 100644
--- a/share/man/man4/vt.4
+++ b/share/man/man4/vt.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 2, 2014
+.Dd October 16, 2014
 .Dt "VIRTUAL TERMINALS" 4
 .Os
 .Sh NAME
@@ -45,7 +45,15 @@ In
 .Xr loader.conf 5 :
 .Cd hw.vga.textmode=1
 .Cd kern.vty=vt
-.Cd kern.vt.spclkeys=15
+.Pp
+In
+.Xr loader.conf 5 or
+.Xr sysctl.conf 5 :
+.Cd kern.vt.kbd_halt=1
+.Cd kern.vt.kbd_poweroff=1
+.Cd kern.vt.kbd_reboot=1
+.Cd kern.vt.kbd_debug=1
+.Cd kern.vt.kbd_panic=0
 .Sh DESCRIPTION
 The
 .Nm
@@ -185,30 +193,41 @@ Set to 1 to use virtual terminals in text mode instead of graphics mode.
 Features that require graphics mode, like loadable fonts, will be
 disabled.
 .It Va kern.vty
-When both
-.Nm
-and
-.Xr sc 4 have been compiled into the kernel, the one to use for the
-system console can be selected by setting this value to
+Set this value to
 .Ql vt
 or
-.Ql sc .
-If this value is not set,
+.Ql sc
+to override the default driver used for the system console.
+By default,
 .Xr sc 4
-is used.
-.It Va kern.vt.spclkeys
-bitmap of allowed special keys. 1 is enabled, 0 is disabled. Encoded as:
-.Bl -tag -compact -width 0x000000
-.It 0x0001
-Debug request key combination. (Ctrl+Alt+Esc)
-.It 0x0002
-Reboot. (Ctrl+Alt+Del)
-.It 0x0004
-Halt.
-.It 0x0008
-Power down.
-.El
-Default is 15, all enabled.
+is used on computers that boot from BIOS, and
+.Nm
+is used on computers that boot from UEFI.
+.Sh KEYBOARD SYSCTL TUNABLES
+These settings control whether certain special key combinations are enabled or
+ignored.
+The specific key combinations can be configured by using a
+.Xr keymap 5
+file.
+.Pp
+These settings can be entered at the
+.Xr loader 8
+prompt or in
+.Xr loader.conf 5
+and can also be changed at runtime with the
+.Xr sysctl 8
+command.
+.Bl -tag -width indent
+.It Va kern.vt.kbd_halt
+Enable halt keyboard combination.
+.It Va kern.vt.kbd_poweroff
+Enable power off key combination.
+.It Va kern.vt.kbd_reboot.
+Enable reboot key combination, usually Ctrl+Alt+Del.
+.It Va kern.vt.kbd_debug
+Enable debug request key combination, usually Ctrl+Alt+Esc.
+.It Va kern.vt.kbd_panic
+Enable panic key combination.
 .El
 .Sh FILES
 .Bl -tag -width /usr/share/vt/keymaps/* -compact