Provide ability to disable kbdmux(4) with the hint.kbdmux.0.disabled="1" hint.

Document hint in the kbdmux(4) man page.

Requested by:	scottl
MFC after:	1 day

share/man/man4/kbdmux.4

@@ -9,6 +9,10 @@
 .Nd "keyboard multiplexer"
 .Sh SYNOPSIS
 .Cd "device kbdmux"
+.Pp
+In
+.Pa /boot/device.hints :
+.Cd hint.kbdmux.0.disabled="1"
 .Sh DESCRIPTION
 The
 .Nm

sys/dev/kbdmux/kbdmux.c

@@ -34,6 +34,7 @@
 #include "opt_kbd.h"
 
 #include <sys/param.h>
+#include <sys/bus.h>
 #include <sys/conf.h>
 #include <sys/consio.h>
 #include <sys/fcntl.h>
@@ -368,6 +369,9 @@ kbdmux_configure(int flags)
 static int
 kbdmux_probe(int unit, void *arg, int flags)
 {
+	if (resource_disabled(KEYBOARD_NAME, unit))
+		return (ENXIO);
+
 	return (0);
 }
 

sys/modules/kbdmux/Makefile

@@ -4,7 +4,7 @@
 .PATH: ${.CURDIR}/../../dev/kbdmux
 
 KMOD=	kbdmux
-SRCS=	kbdmux.c opt_kbd.h
+SRCS=	kbdmux.c opt_kbd.h bus_if.h device_if.h
 
 .if !defined(KERNBUILDDIR)
 opt_kbd.h: