doc/en/dri-howto.xml

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<guide link="/doc/en/dri-howto.xml">
<title>Hardware 3D Acceleration Guide</title>
<author title="Author">
<mail link="spyderous@gentoo.org">Donnie Berkholz</mail>
</author>
<author title="Editor">
<mail link="peesh@gentoo.org">Jorge Paulo</mail>
</author>

<abstract>
This document is a guide to getting 3D acceleration working using XFree-DRM 
with XFree86 in Gentoo Linux.
</abstract>

<license/>

<version>1.0.3</version>
<date>June 21st, 2004</date>

<chapter>
<title>Introduction</title>
<section>
<title>What is hardware 3D acceleration and why do I want it?</title>
<body>

<p>
With hardware 3D acceleration, three-dimensional rendering uses the graphics 
processor on your video card instead of taking up valuable CPU resources 
drawing 3D images. It's also referred to as "hardware acceleration" instead of 
"software acceleration" because without this 3D acceleration your CPU is forced
to draw everything itself using the Mesa software rendering libraries, which 
takes up quite a bit of processing power. While XFree86 typically supports 2D
hardware acceleration, it often lacks hardware 3D acceleration. 
Three-dimensional hardware acceleration is valuable in situations requiring 
rendering of 3D objects such as games, 3D CAD and modeling.
</p>

</body>
</section>
<section>
<title>How do I get hardware 3D acceleration?</title>
<body>

<p>
In many cases, both binary and open-source drivers exist. Open-source drivers 
are preferable since we're using Linux and open source is one of its underlying
principles. Sometimes, binary drivers are the only option, like with nVidia's 
cards. Binary drivers include media-video/nvidia-kernel and 
media-video/nvidia-glx for nVidia cards, media-video/mgavideo for Matrox cards 
and media-video/ati-drivers for ATI cards. Other open-source drivers include 
media-video/kyro-kernel for KyroII cards and media-video/ati-gatos for ATI 
cards, which aim to support ATI's video capabilities more fully.
</p>

</body>
</section>
<section>
<title>What is DRI?</title>
<body>

<p>
The Direct Rendering Infrastructure (<uri 
link="http://dri.sourceforge.net">dri.sourceforge.net</uri>), also known as the 
DRI, is a framework for allowing direct access to graphics hardware in a safe 
and efficient manner. It includes changes to the X server, to several client 
libraries and to the kernel. The first major use for the DRI is to create fast 
OpenGL implementations.
</p>

</body>
</section>
<section>
<title>What is XFree-DRM and how does it relate to regular XFree86?</title>
<body>

<p>
XFree-DRM is an <e>enhancement</e> to XFree86 that adds 3D acceleration for 
cards by adding the kernel module necessary for direct rendering.
</p>

</body>
</section>
<section>
<title>Purpose</title>
<body>

<p>
This guide is for people who can't get direct rendering working with just 
XFree. XFree-DRM works for 3dfx, gamma, i8x0, matrox, rage128, radeon, mach64 
(as of xfree-drm-4.3.0-r7) and sis300 series drivers.  Since the 2.4 kernels' 
Direct Rendering Manager (DRM) doesn't support XFree 4.3, the xfree-drm package
is needed. If you're using a 2.6 kernel, its DRM supports XFree 4.3; Gentoo's 
XFree-DRM package is not yet working on 2.6 kernels. See the <uri 
link="http://dri.sourceforge.net">DRI homepage</uri> for more info and 
documentation.
</p>

</body>
</section>
<section>
<title>Feedback</title>
<body>

<p>
With suggestions, questions, etc., e-mail <mail 
link="spyderous@gentoo.org">Donnie Berkholz</mail>.
</p>

</body>
</section>
</chapter>

<chapter>
<title>Install XFree86 and configure your kernel</title>
<section>
<title>Install XFree86</title>
<body>

<pre caption="Installing XFree86">
# <i>emerge x11-base/xfree</i>
</pre>

</body>
</section>
<section>
<title>Configure your kernel</title>
<body>

<p>
Probe for your chipset and enable just that one.
</p>

<pre caption="Checking your AGP chipset">
# <i>emerge pciutils; lspci | grep AGP</i>
# <i>00:01.0 PCI bridge: Intel Corp. 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 03)</i>
<codenote>Your output may not match the above due to different hardware.</codenote>
</pre>

<p>
Most, if not all, kernels should have these options. This was configured using 
gentoo-sources-2.4.20-r5.
</p>

<pre caption="Configuring the kernel">
# <i>ls -l /usr/src/linux </i>
lrwxrwxrwx    1 root     root           22 May 29 18:20 /usr/src/linux -> linux-2.4.20-gentoo-r5
<codenote>Make sure /usr/src/linux links to your current kernel.</codenote>
# <i>cd /usr/src/linux</i>
# <i>make menuconfig</i>
</pre>

<pre caption="make menuconfig options">
Processor type and features ---&gt;
&lt;*&gt; MTRR (Memory Type Range Register) support
Character devices ---&gt;
&lt;M&gt; /dev/agpgart (AGP Support)
[*] Intel 440LX/BX/GX and I815/I820/I830M/I830MP/I840/I845/I850/I860 support
<codenote>Enable your chipset instead of the above.</codenote>
[ ] Direct Rendering Manager (XFree86 DRI support)
</pre>

<p>
Make sure the Direct Rendering Manager (DRM) is <e>off</e>. The XFree-DRM 
package will provide its own. The 2.4 kernel's version is for XFree 4.2.
</p>

</body>
</section>
<section>
<title>Compile and install your kernel</title>
<body>

<pre caption="Compiling and installing kernel">
# <i>make dep &amp;&amp; make clean bzImage modules modules_install</i>
# <i>mount /boot</i>
# <i>cp arch/i386/boot/bzImage /boot</i>
</pre>

<p>
If you want your kernel to be named something other than bzImage, be sure to 
copy to /boot/yourname instead. Don't forget to set up grub.conf or lilo.conf 
and run /sbin/lilo if you use LILO.
</p>

</body>
</section>
</chapter>

<chapter>
<title>Install XFree-DRM and configure direct rendering</title>
<section>
<title>Install XFree-DRM</title>
<body>

<pre caption="Installing XFree-DRM">
# <i>ACCEPT_KEYWORDS="~x86" emerge xfree-drm</i>
</pre>

</body>
</section>
<section>
<title>Configure XF86Config</title>
<body>

<p>
Open <path>/etc/X11/XF86Config</path> with your favorite text editor and edit 
it to enable DRI and GLX.
</p>

<pre caption="XF86Config">
...
Section "Module"
  Load "dri"
  Load "glx"
  ...
EndSection
...
Section "Device"
  Driver "radeon"
  ...
EndSection
...
Section "dri"
  Mode 0666
EndSection
</pre>

<p>
If you are using a different driver, replace "radeon" with yours.
</p>

</body>
</section>
</chapter>

<chapter>
<title>Test 3D acceleration</title>
<section>
<title>Reboot to the new kernel</title>
<body>

<p>
Reboot your computer to your new kernel. It's time to see if you have direct 
rendering and how good it is.
</p>

<pre caption="Testing rendering">
# <i>startx</i>
<codenote>No need to load modules for your driver or agpgart, if you compiled agpgart as a module.</codenote>
<codenote>They will be loaded automatically.</codenote>
# <i>glxinfo | grep rendering</i>
direct rendering: Yes
<codenote>If it says "No," you don't have 3D acceleration.</codenote>
# <i>glxgears</i>
<codenote>Test your frames per second (FPS) at the default size. The number should be </codenote>
<codenote>significantly higher than before installing xfree-drm. Do this while the CPU is as idle as possible.</codenote>
</pre>

</body>
</section>
</chapter>

<chapter>
<title>Using the CVS sources</title>
<section>
<body>

<warn>
Don't do this if the package worked.
</warn>

<note>
By their nature, CVS sources are always changing.  Your configuration may not 
look exactly like the one below.
</note>

</body>
</section>
<section>
<title>Do you need the CVS?</title>
<body>

<p>
First you have to check whether the xfree-drm package works. If it doesn't and 
you have checked your logs to verify it's not a configuration error, you might 
want to consider the CVS sources. There are also daily driver snapshots 
available if you do not wish to build the full CVS.
</p>

</body>
</section>
<section>
<title>Do the CVS sources support your card?</title>
<body>

<p>
Check the DRI <uri
link="http://dri.sourceforge.net/cgi-bin/moin.cgi/Status">supported cards
list</uri> to see if the CVS supports your card. Even if it doesn't, but it
supports a similar card, try it.
</p>

<warn>
"Linux 2.4 doesn't support agp 8x, so I had to go find a backport. The backport 
works .... it doesn't patch quite properly, and it requires 2.4.21 (I've only 
gotten it to work with vanilla, straight from the tarball (not ebuild)). First 
go get the 2.4.20-2.4.21 patch from kernel.org .... (then get the patch,) It 
was on a mailing list somewhere. It doesn't patch cleanly -- one file fails, 
the pci_ids.h file, but if you actually read the file and the reject list, it's
very easy to fix. But it does load, and it gives me 1600x1200 with video 
(although a bit slow b/c of lack of dga) with xfree-drm." (SanityInAnarchy on 
#gentoo)
</warn>

<impo>
The patch is a little tricky to work with but <uri 
link="http://www.ussg.iu.edu/hypermail/linux/kernel/0302.2/att-1618/01-agp3.diff.bz2">here's 
the link</uri>. If you can disable 8X AGP in your BIOS, change it to 4X and you 
may not need the patch.
</impo>

</body>
</section>
<section>
<title>Install the CVS sources</title>
<body>

<p>
Follow this guide through "Compile and install your kernel." Then continue with
this guide, which tracks step 6 of the <uri
link="http://dri.sourceforge.net/cgi-bin/moin.cgi/Building">DRI compilation
guide</uri> and follows it through step 8.3.
</p>

</body>
</section>
<section>
<title>Anonymous CVS download</title>
<body>

<p>
Create a directory to store the CVS files:
</p>

<pre caption="Create a directory for CVS">
# <i>cd ~</i>
# <i>mkdir DRI-CVS</i>
</pre>

<p>
Check out the CVS sources:
</p>

<pre caption="Check out CVS sources">
# <i>cd ~/DRI-CVS</i>
# <i>cvs -d:pserver:anonymous@cvs.dri.sourceforge.net:/cvsroot/dri login</i>
<codenote>(hit ENTER when prompted for a password)</codenote>
# <i>cvs -z3 -d:pserver:anonymous@cvs.dri.sourceforge.net:/cvsroot/dri co xc</i>
<codenote>The -z3 flag causes compression to be used to reduce the download time.</codenote>
</pre>

</body>
</section>
<section>
<title>Updating your CVS sources</title>
<body>

<p>
In the future you'll want to occasionally update your local copy of the DRI 
source code to get the latest changes. This can be done with:
</p>

<pre caption="Update local copy">
# <i>cd ~/DRI-CVS</i>
# <i>cvs -z3 update -dA xc</i>
<codenote>The -d flag causes any new subdirectories to be created.</codenote>
<codenote>The -A flag causes most recent trunk sources to be fetched, not branch sources.</codenote>
</pre>

</body>
</section>
<section>
<title>Make a build tree</title>
<body>

<p>
Rather than placing object files and library files right in the source tree, 
they're instead put into a parallel <e>build</e> tree. The build tree is made 
with the <c>lndir</c> command:
</p>

<pre caption="Creating a parallel build tree">
# <i>cd ~/DRI-CVS</i>
# <i>ln -s xc XFree40</i>
# <i>mkdir build; cd build</i>
# <i>lndir -silent -ignorelinks ../XFree40</i>
</pre>

<p>
The build tree will be populated with symbolic links which point back into the 
CVS source tree. Advanced users may have several build trees for compiling and 
testing with different options.
</p>

</body>
</section>
<section>
<title>Edit the host.def file</title>
<body>

<p>
The <path>~/DRI-CVS/build/xc/config/cf/host.def</path> file is used to 
configure the XFree86 build process. You can change it to customize your build 
options or make adjustments for your particular system configuration. The 
default host.def file will look something like this:
</p>

<pre caption="host.def">
#define DefaultCCOptions -Wall
<codenote>For i386:</codenote>
#define DefaultGcc2i386Opt -O2
<codenote>For Alpha:</codenote>
#define DefaultGcc2AxpOpt -O2 -mcpu=ev6 (or similar)
<codenote>For all architectures</codenote>
#define LibraryCDebugFlags -O2
#define BuildServersOnly YES
#define XF86CardDrivers vga tdfx mga ati i810
#define LinuxDistribution LinuxRedHat
#define DefaultCCOptions -ansi GccWarningOptions -pipe
#define BuildXF86DRI YES
/* Optionally turn these on for debugging */
/* #define GlxBuiltInTdfx YES */
/* #define GlxBuiltInMga YES */
/* #define GlxBuiltInR128 YES */
/* #define GlxBuiltInRadeon YES */
/* #define DoLoadableServer NO */
#define SharedLibFont NO
</pre>

<pre caption="host.def continued">
<codenote>Note the XF86CardDrivers line to be sure your card's driver is listed.</codenote>
<codenote>If you want to enable 3DNow! optimizations in Mesa and the DRI drivers, you should add the following:</codenote>
#define MesaUse3DNow YES
<codenote>You don't have to be using an AMD processor to enable this option.</codenote>
<codenote>The DRI will look for 3DNow! support at runtime and only enable it if applicable.</codenote>
</pre>

<p>
If you want to enable SSE optimizations in Mesa and the DRI drivers, you must 
upgrade to a Linux 2.4.x kernel. Mesa will verify that SSE is supported by both
your processor and your operating system, but to build Mesa inside the DRI you 
need to have the Linux 2.4.x kernel headers in <path>/usr/src/linux</path>. If 
you enable SSE optimizations with an earlier version of the Linux kernel in 
<path>/usr/src/linux</path>, Mesa will not compile. You have been warned. If
you do have a 2.4.x kernel, you should add the following:
</p>

<pre caption="Update on host.def">
#define MesaUseKatmai YES
</pre>

</body>
</section>
<section>
<title>Compile the XFree86/DRI tree</title>
<body>

<p>
To compile the complete DRI tree:
</p>

<pre caption="Compile the DRI tree">
# <i>cd ~/DRI-CVS/build/xc/</i>
# <i>make World &gt;&amp; world.log</i>
</pre>

<p>
It may also be necessary to do the following, depending on what you placed in 
host.def:
</p>

<pre caption="Further compiling steps">
# <i>cd ~/DRI-CVS/build/xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel</i>
# <i>make -f Makefile.linux radeon.o</i>
<codenote>Replace radeon with your driver.</codenote>
</pre>

<p>
With the default compilation flags it's normal to get a lot of warnings during 
compilation. Building will take some time so you may want to go check your 
email or visit slashdot.
</p>

<warn>
Do not use the -j option with make (i.e., do not use distcc). It's reported that
it does not work with XFree86/DRI.
</warn>

<p>
Using your text editor, examine world.log for errors by searching for the 
pattern ***.
</p>

</body>
</section>
<section>
<title>Install the CVS</title>
<body>

<p>
Verify that the DRI kernel module(s) for your system were built:
</p>

<pre caption="Verification">
# <i>cd ~/DRI-CVS/build/xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel; ls</i>
</pre>

<p>
For the 3dfx Voodoo, you should see <path>tdfx.o</path>. For the Matrox 
G200/G400, you should see <path>mga.o</path>. For the ATI Rage 128, you should 
see <path>r128.o</path>. For the ATI Radeon, you should see 
<path>radeon.o</path>. For the Intel i810, you should see <path>i810.o</path>. 
If the DRI kernel module(s) failed to build, you should verify that you're 
using the right version of the Linux kernel. The most recent kernels are not 
always supported.
</p>

<p>
Install over your XFree86 installation. You may wish to back up xfree.
</p>

<pre caption="Backing up XFree">
# <i>quickpkg xfree</i>
<codenote>This backs up your XFree86 package.</codenote>
# <i>make install</i>
</pre>

<p>
Follow the "Configure XF86Config" section above.
</p>

<p>
To load the appropriate DRM module in your running kernel, copy the kernel 
module to <path>/lib/modules/`uname -r`/kernel/drivers/char/drm/</path> then 
run <c>modules-update</c> and restart your X server. If you're not running the 
kernel you'll be using it in, instead of <c>`uname -r`,</c> use that kernel's 
name.
</p>

<warn>
Make sure you first unload any older DRI kernel modules that might be already 
loaded. Note that some DRM modules require that the agpgart module be loaded 
first.
</warn>

</body>
</section>
</chapter>

<chapter>
<title>Tweak your performance</title>
<section>
<title>Get the most out of direct rendering</title>
<body>

<p>
A few options may increase performance by up to 30 percent (or more) over the 
default. Set them in <path>/etc/X11/XF86Config</path>.
</p>

<pre caption="XF86Config">
Section "Device"
  Option     "AGPMode" "4"
  <codenote>This increased FPS from 609 to 618.</codenote>
  Option     "AGPFastWrite" "True"
  <codenote>This had no measurable effect, but it may increase instability of your computer.</codenote>
  <codenote>You may also need to set it in your BIOS.</codenote>
  Option     "EnablePageFlip" "True"
  <codenote>This improved FPS from 618 to 702. It also is "risky" but few people have reported problems.</codenote>
  ...
EndSection
</pre>

<p>
If you want to set even more features, check out the <uri 
link="http://dri.sourceforge.net/doc/dri_driver_features.phtml">features 
listing</uri> on the DRI Web site.
</p>

</body>
</section>
</chapter>

<chapter>
<title>Troubleshooting</title>
<section>
<title>It doesn't work. I just recompiled my kernel or switched to a new one.</title>
<body>

<p>
Whenever you rebuild your kernel or switch to another kernel, you'll have to 
rebuild the kernel module.  Note that you don't need to remerge xfree, but you 
will need to remerge xfree-drm.
</p>

</body>
</section>

<section>
<title>It doesn't work. I don't have rendering, and I can't tell why.</title>
<body>

<p>
Try <c>insmod radeon</c> before you start the X server. Also, try building 
agpgart into the kernel instead of as a module.
</p>

</body>
</section>
<section>
<title>When I startx, I get this error: "[drm] failed to load kernel module agpgart"</title>
<body>

<p>
That's because you compiled agpgart into the kernel instead of as a module. 
Ignore it unless you're having problems.
</p>

</body>
</section>
<section>
<title>Direct rendering doesn't work, and in /var/log/XFree86.0.log I have an error about driver version too low.</title>
<body>

<p>
You aren't using the xfree-drm driver. Check if you compiled DRM and the driver 
into the kernel; you shouldn't have.
</p>

</body>
</section>
<section>
<title>I have a Radeon, and I want TV-Out.</title>
<body>

<p>
Check out ati-gatos drivers. <c>emerge -s gatos</c>.
</p>

</body>
</section>
<section>
<title>It doesn't work. My card is so incredibly new and cool that it isn't supported at all.</title>
<body>

<p>
Try out the binary drivers. For ati-drivers, a listing is at 
<uri>http://www.schneider-digital.de/html/download_ati.html</uri>. If those 
don't support it, use fbdev. It's slow, but it works.
</p>

</body>
</section>
<section>
<title>I have a PCI card and it doesn't work.  Help!</title>
<body>

<p>
In section "Device" enable ForcePCIMode. 
</p>

<pre caption="Enabling ForcePCIMode">
Option "ForcePCIMode" "True"
</pre>

</body>
</section>
</chapter>

<chapter>
<title>Acknowledgments</title>
<section>
<body>

<ol>
  <li>
    Christopher Webber for suggesting a troubleshooting question about changing 
    or recompiling kernels
  </li>
  <li>
    Steve, for suggesting consistency between the cases of dri and DRI in 
    XF86Config
  </li>
</ol>

</body>
</section>
</chapter>

<chapter>
<title>References</title>
<section>
<body>

<ol>
  <li>http://forums.gentoo.org/viewtopic.php?t=46681</li>
  <li>http://forums.gentoo.org/viewtopic.php?t=29264</li>
  <li>http://dri.sourceforge.net/</li>
  <li>http://www.retinalburn.net/linux/dri_status.html</li>
</ol>

</body>
</section>
</chapter>
</guide>