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Diffstat (limited to 'lkm/ap/ap.4')
| -rw-r--r-- | lkm/ap/ap.4 | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/lkm/ap/ap.4 b/lkm/ap/ap.4 new file mode 100644 index 00000000000..db3d22800f1 --- /dev/null +++ b/lkm/ap/ap.4 @@ -0,0 +1,75 @@ +.\" $OpenBSD: ap.4,v 1.1 1997/01/19 12:29:25 mickey Exp $ +.\" +.\" Copyright (c) 1991 The Regents of the University of California. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" 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). + |