diff options
author | Ralf Baechle <ralf@linux-mips.org> | 1998-06-30 00:21:34 +0000 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 1998-06-30 00:21:34 +0000 |
commit | 3917ac5846dd0f9ad1238166f90caab9912052e6 (patch) | |
tree | 1c298935def4f29edb39192365a65d73de999155 /Documentation/mtrr.txt | |
parent | af2f803c8b2d469fe38e4a7ce952658dfcb6681a (diff) |
o Merge with Linux 2.1.100.
o Cleanup the machine dependencies of floppy and rtc. The driver for
the Dallas thingy in the Indy is still missing.
o Handle allocation of zero'd pages correct for R4000SC / R4400SC.
o Page colouring shit to match the virtual and physical colour of all
mapped pages. This tends to produce extreme fragmentation problems,
so it's deactivated for now. Users of R4000SC / R4400SC may re-enable
the code in arch/mips/mm/init.c by removing the definition of
CONF_GIVE_A_SHIT_ABOUT_COLOURS. Should get them somewhat further -
but don't shake to hard ...
o Fixed ptrace(2)-ing of syscalls, strace is now working again.
o Fix the interrupt forwarding from the keyboard driver to the psaux
driver, PS/2 mice are now working on the Indy. The fix is somewhat
broken as it prevents generic kernels for Indy and machines which handle
things different.
o Things I can't remember.
Diffstat (limited to 'Documentation/mtrr.txt')
-rw-r--r-- | Documentation/mtrr.txt | 61 |
1 files changed, 44 insertions, 17 deletions
diff --git a/Documentation/mtrr.txt b/Documentation/mtrr.txt index 4236cff13..4b6264bcd 100644 --- a/Documentation/mtrr.txt +++ b/Documentation/mtrr.txt @@ -1,15 +1,15 @@ MTRR (Memory Type Range Register) control -17 Dec 1997 +2 May 1998 Richard Gooch <rgooch@atnf.csiro.au> - On Intel Pentium Pro systems the Memory Type Range Registers (MTRRs) - may be used to control processor access to memory ranges. This is - most useful when you have a video (VGA) card on the PCI - bus. Enabling write-combining allows PCI write transfers to be - combined into a larger transfer before bursting over the PCI - bus. This can increase performance of image write operations 2.5 - times or more. + On Intel Pentium Pro/Pentium II systems the Memory Type Range + Registers (MTRRs) may be used to control processor access to memory + ranges. This is most useful when you have a video (VGA) card on a + PCI or AGP bus. Enabling write-combining allows bus write transfers + to be combined into a larger transfer before bursting over the + PCI/AGP bus. This can increase performance of image write operations + 2.5 times or more. The CONFIG_MTRR option creates a /proc/mtrr file which may be used to manipulate your MTRRs. Typically the X server should use @@ -30,13 +30,40 @@ Reading MTRRs from the shell: % cat /proc/mtrr reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 -reg05: base=0x80000000 (2048MB), size= 4MB: write-combining, count=1 =============================================================================== Creating MTRRs from the shell: -% echo "base=0x80000000 size=0x400000 type=write-combining" >! /proc/mtrr +# echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr + +And the result thereof: +% cat /proc/mtrr +reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 +reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 +reg02: base=0xf8000000 (3968MB), size= 4MB: write-combining, count=1 + +This is for videoram at base address 0xf8000000 and size 4 MBytes. To +find out your base address, you need to look at the output of your X +server, which tells you where the linear framebuffer address is. A +typical line that you may get is: + +(--) S3: PCI: 968 rev 0, Linear FB @ 0xf8000000 + +Note that you should only use the value from the X server, as it may +move the framebuffer base address, so the only value you can trust is +that reported by the X server. + +To find out the size of your framebuffer (what, you don't actually +know?), the following line will tell you: + +(--) S3: videoram: 4096k + +That's 4 MBytes, which is 0x400000 bytes (in hexadecimal). +A patch is being written for XFree86 which will make this automatic: +in other words the X server will manipulate /proc/mtrr using the +ioctl() interface, so users won't have to do anything. If you use a +commercial X server, lobby your vendor to add support for MTRRs. =============================================================================== Removing MTRRs from the shell: -% echo "disable=5" >! /proc/mtrr +% echo "disable=2" >! /proc/mtrr =============================================================================== Reading MTRRs from a C programme using ioctl()'s: @@ -44,7 +71,7 @@ Reading MTRRs from a C programme using ioctl()'s: Source file for mtrr-show (example programme to show MTRRs using ioctl()'s) - Copyright (C) 1997 Richard Gooch + Copyright (C) 1997-1998 Richard Gooch This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -72,7 +99,7 @@ Reading MTRRs from a C programme using ioctl()'s: Written by Richard Gooch 17-DEC-1997 - Last updated by Richard Gooch 17-DEC-1997 + Last updated by Richard Gooch 2-MAY-1998 */ @@ -84,7 +111,7 @@ Reading MTRRs from a C programme using ioctl()'s: #include <sys/ioctl.h> #include <errno.h> #define MTRR_NEED_STRINGS -#include <linux/mtrr.h> +#include <asm/mtrr.h> #define TRUE 1 #define FALSE 0 @@ -130,7 +157,7 @@ Creating MTRRs from a C programme using ioctl()'s: Source file for mtrr-add (example programme to add an MTRRs using ioctl()) - Copyright (C) 1997 Richard Gooch + Copyright (C) 1997-1998 Richard Gooch This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -158,7 +185,7 @@ Creating MTRRs from a C programme using ioctl()'s: Written by Richard Gooch 17-DEC-1997 - Last updated by Richard Gooch 17-DEC-1997 + Last updated by Richard Gooch 2-MAY-1998 */ @@ -172,7 +199,7 @@ Creating MTRRs from a C programme using ioctl()'s: #include <sys/ioctl.h> #include <errno.h> #define MTRR_NEED_STRINGS -#include <linux/mtrr.h> +#include <asm/mtrr.h> #define TRUE 1 #define FALSE 0 |