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.TH "MTRR_ADD" "9" "17 July 2003" "" ""

.SH NAME
mtrr_add \- Add a memory type region
.SH SYNOPSIS
.sp
\fB
.sp
int mtrr_add  (unsigned long \fIbase\fB, unsigned long \fIsize\fB, unsigned int \fItype\fB, char \fIincrement\fB);
\fR
.SH "ARGUMENTS"
.TP
\fB\fIbase\fB\fR
Physical base address of region
.TP
\fB\fIsize\fB\fR
Physical size of region
.TP
\fB\fItype\fB\fR
Type of MTRR desired
.TP
\fB\fIincrement\fB\fR
If this is true do usage counting on the region
.SH "DESCRIPTION"
.PP
Memory type region registers control the caching on newer Intel and
non Intel processors. This function allows drivers to request an
MTRR is added. The details and hardware specifics of each processor's
implementation are hidden from the caller, but nevertheless the 
caller should expect to need to provide a power of two size on an
equivalent power of two boundary.
.PP
If the region cannot be added either because all regions are in use
or the CPU cannot support it a negative value is returned. On success
the register number for this entry is returned, but should be treated
as a cookie only.
.PP
On a multiprocessor machine the changes are made to all processors.
This is required on x86 by the Intel processors.
.PP
The available types are
.PP
MTRR_TYPE_UNCACHABLE - No caching
.PP
MTRR_TYPE_WRBACK - Write data back in bursts whenever
.PP
MTRR_TYPE_WRCOMB - Write data back soon but allow bursts
.PP
MTRR_TYPE_WRTHROUGH - Cache reads but not writes
.SH "BUGS"
.PP
Needs a quiet flag for the cases where drivers do not mind
failures and do not wish system log messages to be sent.
.SH "ABOUT THIS DOCUMENT"
.PP
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later
version.
.PP
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
.PP
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
.PP
For more details see the file COPYING in the source
distribution of Linux.
.PP
If you have comments on the formatting of this manpage, then please contact
Michael Still (mikal@stillhq.com).
.PP
This documentation was generated with kernel version 2.5.71.