.\"	$OpenBSD: ap.4,v 1.1 1997/01/19 12:29:25 mickey Exp $
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.\"	from: @(#)mem.4	5.3 (Berkeley) 5/2/91
.\"	from Id: mem.4,v 1.1.1.1 1995/10/18 08:44:29 deraadt Exp
.\"
.Dd Jan 19, 1997
.Dt AP 4
.Os
.Sh NAME
.Nm xf86
.Nd XFree86 Framebuffer aperture driver
.Sh DESCRIPTION
This module was written to help work around the security feature of
the OS that prevents read/write access to /dev/mem.
.Pp
XFree86 can take advantage of having direct access to video
memory (especially with VLB and PCI cards) and even requires it for
the P9000 server.
.Pp
This driver works like the standard
.Nm /dev/mem
driver. It just allows
mapping of the VGA framebuffer even if kernel security level is > 0.
The driver only implements the
.Xr open 2 ,
.Xr close 2 ,
.Xr mmap 2
calls. In
order not to defeat kernel security, only one open() at a time is
allowed and only a process with effective user id of 0 can perform
it. So while you're running XFree86, no other process will be allowed
to open
.Nm /dev/xf86
.Sh FILES
.Bl -tag -width Pa -compact
.It Pa /dev/xf86
.El
.Sh SEE ALSO
.Xr mem 4 ,
.Xr kmem 4
.Sh HISTORY
This work is heavily inspired from the Solaris x86 aperture driver by
Doug Anson (danson@lgc.com) and David Holland (davidh@use.com).