From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1C71C43219 for ; Sat, 27 Apr 2019 18:11:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39620206BF for ; Sat, 27 Apr 2019 18:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556388662; bh=r3FVGaD3L41wZjI2fGUNH6AR0ct4t5AZ3+2vTKvwYHA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=xdTHE5zgU4fREO2iDtgDy3CRGFibEM45pMaq1hh3i3lxECsxlbOiCjmPH+J+xIuHq YBfnGt+RSzVE+GgxzklO6mGm0YuAw/57XuoOIdxuTUH+tTgfRQ5wbdhI3na/dL7uTN gDvUNBhN2C0bdZigwRWcDV+a1V33/+6oX/ZHBIdk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726218AbfD0SLB (ORCPT ); Sat, 27 Apr 2019 14:11:01 -0400 Received: from casper.infradead.org ([85.118.1.10]:51026 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725950AbfD0SLB (ORCPT ); Sat, 27 Apr 2019 14:11:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:Content-Type: MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Iq++5oY7JlBDr2ngOMm/nqDvH6g/yS7QPprVJh4aB3Y=; b=HmaJJgyhoEHxjKaM5jaSOZGNci Ai2gCbmIY1CuvoaCVe8gZqw+eeBwCKsnhrByOCYWWL4ruo+BGaAlxM+gcpPETLP8pc4lJM2zNTqxC 0nQ7AsY+OVBIEs6OZIuj6iGz6WNEkC87CUp1EFf7Vo1OlLJ/tEgZxa1w9latsfGwl5bJ23mJ+FuzS ISenGzCCJemxWxVO8qFGBQLzFAHhg7wX86f8jS9KSSrOFsrSyu3vUXmyNpoBOoCmZFoGTZcEqVQwF 81e6zKqXnxg/LIpSZj5h/KDNgCacuvIV7e6Uwvv7G8hzmD1bcYbTx7d1tcWPMiryqDBiZh2LCtznU kA49I/Ow==; Received: from 177.17.250.151.dynamic.adsl.gvt.net.br ([177.17.250.151] helo=coco.lan) by casper.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hKRmn-0003u0-1k; Sat, 27 Apr 2019 18:10:53 +0000 Date: Sat, 27 Apr 2019 15:10:48 -0300 From: Mauro Carvalho Chehab To: Changbin Du Cc: Jonathan Corbet , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/27] Documentation: x86: convert mtrr.txt to reST Message-ID: <20190427151048.285af7aa@coco.lan> In-Reply-To: <20190427143213.3c0d2286@coco.lan> References: <20190426153150.21228-1-changbin.du@gmail.com> <20190426153150.21228-11-changbin.du@gmail.com> <20190427143213.3c0d2286@coco.lan> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Sat, 27 Apr 2019 14:32:13 -0300 Mauro Carvalho Chehab escreveu: > Em Fri, 26 Apr 2019 23:31:33 +0800 > Changbin Du escreveu: > > > This converts the plain text documentation to reStructuredText format and > > add it to Sphinx TOC tree. No essential content change. > > > > Signed-off-by: Changbin Du > > --- > > Documentation/x86/index.rst | 1 + > > Documentation/x86/mtrr.rst | 350 ++++++++++++++++++++++++++++++++++++ > > Documentation/x86/mtrr.txt | 329 --------------------------------- > > 3 files changed, 351 insertions(+), 329 deletions(-) > > create mode 100644 Documentation/x86/mtrr.rst > > delete mode 100644 Documentation/x86/mtrr.txt > > > > diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst > > index fd54b859db9b..d805962a7238 100644 > > --- a/Documentation/x86/index.rst > > +++ b/Documentation/x86/index.rst > > @@ -16,3 +16,4 @@ Linux x86 Support > > earlyprintk > > zero-page > > tlb > > + mtrr > > diff --git a/Documentation/x86/mtrr.rst b/Documentation/x86/mtrr.rst > > new file mode 100644 > > index 000000000000..72da61022861 > > --- /dev/null > > +++ b/Documentation/x86/mtrr.rst > > @@ -0,0 +1,350 @@ > > +.. SPDX-License-Identifier: GPL-2.0 > > + > > +========================================= > > +MTRR (Memory Type Range Register) control > > +========================================= > > + > > +:Ahthors: - Richard Gooch - 3 Jun 1999 > > + - Luis R. Rodriguez - April 9, 2015 > > Typo: Authors > > > + > > + > > +Phasing out MTRR use > > +==================== > > + > > +MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by > > +drivers on Linux is now completely phased out, device drivers should use > > +arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on > > +non-PAT systems while a no-op but equally effective on PAT enabled systems. > > + > > +Even if Linux does not use MTRRs directly, some x86 platform firmware may still > > +set up MTRRs early before booting the OS. They do this as some platform > > +firmware may still have implemented access to MTRRs which would be controlled > > +and handled by the platform firmware directly. An example of platform use of > > +MTRRs is through the use of SMI handlers, one case could be for fan control, > > +the platform code would need uncachable access to some of its fan control > > +registers. Such platform access does not need any Operating System MTRR code in > > +place other than mtrr_type_lookup() to ensure any OS specific mapping requests > > +are aligned with platform MTRR setup. If MTRRs are only set up by the platform > > +firmware code though and the OS does not make any specific MTRR mapping > > +requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID. > > + > > +For details refer to :doc:`x86/pat`. In time: the reference above is broken: Documentation/x86/mtrr.rst:31: WARNING: unknown document: x86/pat It should be, instead: :doc:`pat` > > I'm in doubt about the block below: > > > + > > +On Intel P6 family processors (Pentium Pro, Pentium II and later) > > +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 Cyrix 6x86, 6x86MX and M II processors have Address Range > > +Registers (ARRs) which provide a similar functionality to MTRRs. For > > +these, the ARRs are used to emulate the MTRRs. > > + > > +The AMD K6-2 (stepping 8 and above) and K6-3 processors have two > > +MTRRs. These are supported. The AMD Athlon family provide 8 Intel > > +style MTRRs. > > + > > +The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These > > +are supported. > > + > > +The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs. > > + > > +The CONFIG_MTRR option creates a /proc/mtrr file which may be used > > +to manipulate your MTRRs. Typically the X server should use > > +this. This should have a reasonably generic interface so that > > +similar control registers on other processors can be easily > > +supported. > > All the above were originally indented, and marked by an horizontal > bar (together with the next paragraph). > > Perhaps the intention there were to mark them as some sort of per-CPU > type notes. > > Anyway, I would preserve the original indentation - possibly > replacing the horizontal bar using non-ReST standard: > > =============================================================================== > > By the ReST equivalent: > > ------------------------------------------------------------------------------- > > Later, if x86 maintainers thing it is worth, they could add a note markup > before the block. > > > + > > +There are two interfaces to /proc/mtrr: one is an ASCII interface > > +which allows you to read and write. The other is an ioctl() > > +interface. The ASCII interface is meant for administration. The > > +ioctl() interface is meant for C programs (i.e. the X server). The > > +interfaces are described below, with sample commands and C code. > > + > > +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 > > + > > +Creating MTRRs from the C-shell:: > > + > > + # echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr > > + > > +or if you use bash:: > > + > > + # 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 video RAM at base address 0xf8000000 and size 4 megabytes. 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 megabytes, 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. > > + > > + > > +Creating overlapping MTRRs > > +========================== > > +:: > > + > > + %echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr > > + %echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr > > + > > +And the results:: > > + > > + % cat /proc/mtrr > > + reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 > > + reg01: base=0xfb000000 (4016MB), size= 16MB: write-combining, count=1 > > + reg02: base=0xfb000000 (4016MB), size= 4kB: uncachable, count=1 > > + > > +Some cards (especially Voodoo Graphics boards) need this 4 kB area > > +excluded from the beginning of the region because it is used for > > +registers. > > + > > +NOTE: You can only create type=uncachable region, if the first > > +region that you created is type=write-combining. > > If you don't want to use a note markup, I would, at least, do: > > Note: > You can only create type=uncachable region, if the first > region that you created is type=write-combining. > > > + > > + > > +Removing MTRRs from the C-shel > > +============================== > > There's also a typo above: C-shel -> C-shell... > > > +:: > > + > > + % echo "disable=2" >! /proc/mtrr > > + > > +or using bash:: > > + > > + % echo "disable=2" >| /proc/mtrr > > > Yet, I would, instead rewrite this block as: > > > Removing MTRRs > ============== > > Using C-shell:: > > % echo "disable=2" >! /proc/mtrr > > or using bash:: > > % echo "disable=2" >| /proc/mtrr > > > As it contains both csh and bash instructions there. > > > + > > + > > +Reading MTRRs from a C program using ioctl()'s > > +============================================== > > +:: > > + > > + /* mtrr-show.c > > + > > + Source file for mtrr-show (example program to show MTRRs using ioctl()'s) > > + > > + 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 > > + the Free Software Foundation; either version 2 of the License, or > > + (at your option) any later version. > > + > > + 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. > > + > > + 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., 675 Mass Ave, Cambridge, MA 02139, USA. > > + > > + Richard Gooch may be reached by email at rgooch@atnf.csiro.au > > + The postal address is: > > + Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > > + */ > > + > > + /* > > + This program will use an ioctl() on /proc/mtrr to show the current MTRR > > + settings. This is an alternative to reading /proc/mtrr. > > + > > + > > + Written by Richard Gooch 17-DEC-1997 > > + > > + Last updated by Richard Gooch 2-MAY-1998 > > + > > + > > + */ > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + > > + #define TRUE 1 > > + #define FALSE 0 > > + #define ERRSTRING strerror (errno) > > + > > + static char *mtrr_strings[MTRR_NUM_TYPES] = > > + { > > + "uncachable", /* 0 */ > > + "write-combining", /* 1 */ > > + "?", /* 2 */ > > + "?", /* 3 */ > > + "write-through", /* 4 */ > > + "write-protect", /* 5 */ > > + "write-back", /* 6 */ > > + }; > > + > > + int main () > > + { > > + int fd; > > + struct mtrr_gentry gentry; > > + > > + if ( ( fd = open ("/proc/mtrr", O_RDONLY, 0) ) == -1 ) > > + { > > + if (errno == ENOENT) > > + { > > + fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > > + stderr); > > + exit (1); > > + } > > + fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > > + exit (2); > > + } > > + for (gentry.regnum = 0; ioctl (fd, MTRRIOC_GET_ENTRY, &gentry) == 0; > > + ++gentry.regnum) > > + { > > + if (gentry.size < 1) > > + { > > + fprintf (stderr, "Register: %u disabled\n", gentry.regnum); > > + continue; > > + } > > + fprintf (stderr, "Register: %u base: 0x%lx size: 0x%lx type: %s\n", > > + gentry.regnum, gentry.base, gentry.size, > > + mtrr_strings[gentry.type]); > > + } > > + if (errno == EINVAL) exit (0); > > + fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > > + exit (3); > > + } /* End Function main */ > > + > > + > > +Creating MTRRs from a C programme using ioctl()'s > > +================================================= > > +:: > > + > > + /* mtrr-add.c > > + > > + Source file for mtrr-add (example programme to add an MTRRs using ioctl()) > > + > > + 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 > > + the Free Software Foundation; either version 2 of the License, or > > + (at your option) any later version. > > + > > + 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. > > + > > + 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., 675 Mass Ave, Cambridge, MA 02139, USA. > > + > > + Richard Gooch may be reached by email at rgooch@atnf.csiro.au > > + The postal address is: > > + Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > > + */ > > + > > + /* > > + This programme will use an ioctl() on /proc/mtrr to add an entry. The first > > + available mtrr is used. This is an alternative to writing /proc/mtrr. > > + > > + > > + Written by Richard Gooch 17-DEC-1997 > > + > > + Last updated by Richard Gooch 2-MAY-1998 > > + > > + > > + */ > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + #include > > + > > + #define TRUE 1 > > + #define FALSE 0 > > + #define ERRSTRING strerror (errno) > > + > > + static char *mtrr_strings[MTRR_NUM_TYPES] = > > + { > > + "uncachable", /* 0 */ > > + "write-combining", /* 1 */ > > + "?", /* 2 */ > > + "?", /* 3 */ > > + "write-through", /* 4 */ > > + "write-protect", /* 5 */ > > + "write-back", /* 6 */ > > + }; > > + > > + int main (int argc, char **argv) > > + { > > + int fd; > > + struct mtrr_sentry sentry; > > + > > + if (argc != 4) > > + { > > + fprintf (stderr, "Usage:\tmtrr-add base size type\n"); > > + exit (1); > > + } > > + sentry.base = strtoul (argv[1], NULL, 0); > > + sentry.size = strtoul (argv[2], NULL, 0); > > + for (sentry.type = 0; sentry.type < MTRR_NUM_TYPES; ++sentry.type) > > + { > > + if (strcmp (argv[3], mtrr_strings[sentry.type]) == 0) break; > > + } > > + if (sentry.type >= MTRR_NUM_TYPES) > > + { > > + fprintf (stderr, "Illegal type: \"%s\"\n", argv[3]); > > + exit (2); > > + } > > + if ( ( fd = open ("/proc/mtrr", O_WRONLY, 0) ) == -1 ) > > + { > > + if (errno == ENOENT) > > + { > > + fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > > + stderr); > > + exit (3); > > + } > > + fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > > + exit (4); > > + } > > + if (ioctl (fd, MTRRIOC_ADD_ENTRY, &sentry) == -1) > > + { > > + fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > > + exit (5); > > + } > > + fprintf (stderr, "Sleeping for 5 seconds so you can see the new entry\n"); > > + sleep (5); > > + close (fd); > > + fputs ("I've just closed /proc/mtrr so now the new entry should be gone\n", > > + stderr); > > + } /* End Function main */ > > diff --git a/Documentation/x86/mtrr.txt b/Documentation/x86/mtrr.txt > > deleted file mode 100644 > > index dc3e703913ac..000000000000 > > --- a/Documentation/x86/mtrr.txt > > +++ /dev/null > > @@ -1,329 +0,0 @@ > > -MTRR (Memory Type Range Register) control > > - > > -Richard Gooch - 3 Jun 1999 > > -Luis R. Rodriguez - April 9, 2015 > > - > > -=============================================================================== > > -Phasing out MTRR use > > - > > -MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by > > -drivers on Linux is now completely phased out, device drivers should use > > -arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on > > -non-PAT systems while a no-op but equally effective on PAT enabled systems. > > - > > -Even if Linux does not use MTRRs directly, some x86 platform firmware may still > > -set up MTRRs early before booting the OS. They do this as some platform > > -firmware may still have implemented access to MTRRs which would be controlled > > -and handled by the platform firmware directly. An example of platform use of > > -MTRRs is through the use of SMI handlers, one case could be for fan control, > > -the platform code would need uncachable access to some of its fan control > > -registers. Such platform access does not need any Operating System MTRR code in > > -place other than mtrr_type_lookup() to ensure any OS specific mapping requests > > -are aligned with platform MTRR setup. If MTRRs are only set up by the platform > > -firmware code though and the OS does not make any specific MTRR mapping > > -requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID. > > - > > -For details refer to Documentation/x86/pat.txt. > > - > > -=============================================================================== > > - > > - On Intel P6 family processors (Pentium Pro, Pentium II and later) > > - 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 Cyrix 6x86, 6x86MX and M II processors have Address Range > > - Registers (ARRs) which provide a similar functionality to MTRRs. For > > - these, the ARRs are used to emulate the MTRRs. > > - > > - The AMD K6-2 (stepping 8 and above) and K6-3 processors have two > > - MTRRs. These are supported. The AMD Athlon family provide 8 Intel > > - style MTRRs. > > - > > - The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These > > - are supported. > > - > > - The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs. > > - > > - The CONFIG_MTRR option creates a /proc/mtrr file which may be used > > - to manipulate your MTRRs. Typically the X server should use > > - this. This should have a reasonably generic interface so that > > - similar control registers on other processors can be easily > > - supported. > > - > > - > > -There are two interfaces to /proc/mtrr: one is an ASCII interface > > -which allows you to read and write. The other is an ioctl() > > -interface. The ASCII interface is meant for administration. The > > -ioctl() interface is meant for C programs (i.e. the X server). The > > -interfaces are described below, with sample commands and C code. > > - > > -=============================================================================== > > -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 > > -=============================================================================== > > -Creating MTRRs from the C-shell: > > -# echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr > > -or if you use bash: > > -# 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 video RAM at base address 0xf8000000 and size 4 megabytes. 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 megabytes, 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. > > -=============================================================================== > > -Creating overlapping MTRRs: > > - > > -%echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr > > -%echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr > > - > > -And the results: cat /proc/mtrr > > -reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 > > -reg01: base=0xfb000000 (4016MB), size= 16MB: write-combining, count=1 > > -reg02: base=0xfb000000 (4016MB), size= 4kB: uncachable, count=1 > > - > > -Some cards (especially Voodoo Graphics boards) need this 4 kB area > > -excluded from the beginning of the region because it is used for > > -registers. > > - > > -NOTE: You can only create type=uncachable region, if the first > > -region that you created is type=write-combining. > > -=============================================================================== > > -Removing MTRRs from the C-shell: > > -% echo "disable=2" >! /proc/mtrr > > -or using bash: > > -% echo "disable=2" >| /proc/mtrr > > -=============================================================================== > > -Reading MTRRs from a C program using ioctl()'s: > > - > > -/* mtrr-show.c > > - > > - Source file for mtrr-show (example program to show MTRRs using ioctl()'s) > > - > > - 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 > > - the Free Software Foundation; either version 2 of the License, or > > - (at your option) any later version. > > - > > - 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. > > - > > - 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., 675 Mass Ave, Cambridge, MA 02139, USA. > > - > > - Richard Gooch may be reached by email at rgooch@atnf.csiro.au > > - The postal address is: > > - Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > > -*/ > > - > > -/* > > - This program will use an ioctl() on /proc/mtrr to show the current MTRR > > - settings. This is an alternative to reading /proc/mtrr. > > - > > - > > - Written by Richard Gooch 17-DEC-1997 > > - > > - Last updated by Richard Gooch 2-MAY-1998 > > - > > - > > -*/ > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > - > > -#define TRUE 1 > > -#define FALSE 0 > > -#define ERRSTRING strerror (errno) > > - > > -static char *mtrr_strings[MTRR_NUM_TYPES] = > > -{ > > - "uncachable", /* 0 */ > > - "write-combining", /* 1 */ > > - "?", /* 2 */ > > - "?", /* 3 */ > > - "write-through", /* 4 */ > > - "write-protect", /* 5 */ > > - "write-back", /* 6 */ > > -}; > > - > > -int main () > > -{ > > - int fd; > > - struct mtrr_gentry gentry; > > - > > - if ( ( fd = open ("/proc/mtrr", O_RDONLY, 0) ) == -1 ) > > - { > > - if (errno == ENOENT) > > - { > > - fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > > - stderr); > > - exit (1); > > - } > > - fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > > - exit (2); > > - } > > - for (gentry.regnum = 0; ioctl (fd, MTRRIOC_GET_ENTRY, &gentry) == 0; > > - ++gentry.regnum) > > - { > > - if (gentry.size < 1) > > - { > > - fprintf (stderr, "Register: %u disabled\n", gentry.regnum); > > - continue; > > - } > > - fprintf (stderr, "Register: %u base: 0x%lx size: 0x%lx type: %s\n", > > - gentry.regnum, gentry.base, gentry.size, > > - mtrr_strings[gentry.type]); > > - } > > - if (errno == EINVAL) exit (0); > > - fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > > - exit (3); > > -} /* End Function main */ > > -=============================================================================== > > -Creating MTRRs from a C programme using ioctl()'s: > > - > > -/* mtrr-add.c > > - > > - Source file for mtrr-add (example programme to add an MTRRs using ioctl()) > > - > > - 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 > > - the Free Software Foundation; either version 2 of the License, or > > - (at your option) any later version. > > - > > - 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. > > - > > - 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., 675 Mass Ave, Cambridge, MA 02139, USA. > > - > > - Richard Gooch may be reached by email at rgooch@atnf.csiro.au > > - The postal address is: > > - Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > > -*/ > > - > > -/* > > - This programme will use an ioctl() on /proc/mtrr to add an entry. The first > > - available mtrr is used. This is an alternative to writing /proc/mtrr. > > - > > - > > - Written by Richard Gooch 17-DEC-1997 > > - > > - Last updated by Richard Gooch 2-MAY-1998 > > - > > - > > -*/ > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > -#include > > - > > -#define TRUE 1 > > -#define FALSE 0 > > -#define ERRSTRING strerror (errno) > > - > > -static char *mtrr_strings[MTRR_NUM_TYPES] = > > -{ > > - "uncachable", /* 0 */ > > - "write-combining", /* 1 */ > > - "?", /* 2 */ > > - "?", /* 3 */ > > - "write-through", /* 4 */ > > - "write-protect", /* 5 */ > > - "write-back", /* 6 */ > > -}; > > - > > -int main (int argc, char **argv) > > -{ > > - int fd; > > - struct mtrr_sentry sentry; > > - > > - if (argc != 4) > > - { > > - fprintf (stderr, "Usage:\tmtrr-add base size type\n"); > > - exit (1); > > - } > > - sentry.base = strtoul (argv[1], NULL, 0); > > - sentry.size = strtoul (argv[2], NULL, 0); > > - for (sentry.type = 0; sentry.type < MTRR_NUM_TYPES; ++sentry.type) > > - { > > - if (strcmp (argv[3], mtrr_strings[sentry.type]) == 0) break; > > - } > > - if (sentry.type >= MTRR_NUM_TYPES) > > - { > > - fprintf (stderr, "Illegal type: \"%s\"\n", argv[3]); > > - exit (2); > > - } > > - if ( ( fd = open ("/proc/mtrr", O_WRONLY, 0) ) == -1 ) > > - { > > - if (errno == ENOENT) > > - { > > - fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > > - stderr); > > - exit (3); > > - } > > - fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > > - exit (4); > > - } > > - if (ioctl (fd, MTRRIOC_ADD_ENTRY, &sentry) == -1) > > - { > > - fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > > - exit (5); > > - } > > - fprintf (stderr, "Sleeping for 5 seconds so you can see the new entry\n"); > > - sleep (5); > > - close (fd); > > - fputs ("I've just closed /proc/mtrr so now the new entry should be gone\n", > > - stderr); > > -} /* End Function main */ > > -=============================================================================== > > > > Thanks, > Mauro Thanks, Mauro