glfs/x/installing/xorg-config.xml
Pierre Labastie 6039a3956f Remove PRIME patch, augment Hybrid graphics instructions
+ one unrelated tag

git-svn-id: svn://svn.linuxfromscratch.org/BLFS/trunk/BOOK@19111 af4574ff-66df-0310-9fd7-8a98e5e911e0
2017-08-27 11:41:00 +00:00

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<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY % general-entities SYSTEM "../../general.ent">
%general-entities;
]>
<sect1 id="xorg-config">
<?dbhtml filename="xorg-config.html"?>
<sect1info>
<othername>$LastChangedBy$</othername>
<date>$Date$</date>
</sect1info>
<title>Xorg-&xorg-version; Testing and Configuration</title>
<indexterm zone="xorg-config">
<primary sortas="g-configuring-xorg">Configuring Xorg</primary>
</indexterm>
<sect2 id='X11-testing' xreflabel="Testing Xorg">
<title>Testing Xorg</title>
<note>
<para>
Before starting Xorg for the first time, is is useful to
rebuild the library cache by running <userinput>ldconfig</userinput>
as the <systemitem class="username">root</systemitem> user.
</para>
</note>
<para>
To test the <application>Xorg</application> installation, issue
<command>startx</command>. This command brings up a rudimentary window
manager called <emphasis>twm</emphasis> with three xterm windows and one
xclock window. The xterm window in the upper left is a login terminal and
running <emphasis>exit</emphasis> from this terminal will exit the
<application>X Window</application> session. The third xterm window may
be obscured on your system by the other two xterms.
</para>
<note>
<para>
When testing <application>Xorg</application> with the
<application>twm</application> window manager, there will be several
warnings in the Xorg log file, <filename revision="sysv">
/var/log/Xorg.0.log</filename><filename revision="systemd">
$HOME/.local/share/xorg/Xorg.0.log</filename>, about missing font
files. In addition, there will be several warnings on the text mode
terminal (usually tty1) about missing fonts. These warnings do not
affect functionality, but can be removed if desired by installing
the <xref linkend="xorg7-legacy"/>.
</para>
</note>
<para>
Generally, there is no specific configuration required for
<application>Xorg</application>, but customization is possible. For
details, see <xref linkend='xconfig'/> below.
</para>
</sect2>
<sect2 role="configuration" id="checking-dri" xreflabel="Checking the DRI
installation">
<title>Checking the Direct Rendering Infrastructure (DRI)
Installation</title>
<para>
DRI is a framework for allowing software to access graphics hardware in
a safe and efficient manner. It is installed in
<application>X</application> by default (using
<application>Mesa</application>) if you have a supported video card.
</para>
<para>
To check if DRI drivers are installed properly, check the log file
<filename revision="sysv">/var/log/Xorg.0.log</filename><filename
revision="systemd">$HOME/.local/share/xorg/Xorg.0.log</filename> for
statements such as:
</para>
<screen><literal>(II) intel(0): direct rendering: DRI2 Enabled</literal></screen>
<para>or</para>
<screen><literal>(II) NOUVEAU(0): Loaded DRI module</literal></screen>
<note>
<para>
DRI configuration may differ if you are using alternate drivers, such
as those from
<ulink url="http://www.nvidia.com/page/home.html">NVIDIA</ulink> or
<ulink url="http://www.amd.com/">AMD</ulink>.
</para>
</note>
<para>
Although all users can use software acceleration, any hardware
acceleration (DRI2) is only available to <systemitem
class="username">root</systemitem> and members of the <systemitem
class="groupname">video</systemitem> group, but
<phrase revision="sysv"><emphasis>ConsoleKit2</emphasis></phrase>
<phrase revision="systemd"><emphasis>systemd-logind</emphasis></phrase>
takes care of adding any logged in user to the user ACL's of
<filename>/dev/dri/card*</filename>, the special file(s) allowing access
to hardware acceleration.<phrase revision="systemd"> So, no further
configuration is needed.</phrase>
</para>
<para revision="sysv">
If your driver is supported and <emphasis>ConsoleKit2</emphasis> is not
installed, add any users that might use X to the <systemitem
class="groupname">video</systemitem> group:
</para>
<screen role="root" revision="sysv"><userinput>usermod -a -G video <replaceable>&lt;username&gt;</replaceable></userinput></screen>
<para>
Another way to determine if DRI is working properly is to use one of the
two optionally installed OpenGL demo programs in <xref
linkend="mesa"/>. From an X terminal, run <command>glxinfo</command>
and look for the phrase:
</para>
<screen><computeroutput>name of display: :0
display: :0 screen: 0
direct rendering: Yes</computeroutput></screen>
<para>
If direct rendering is enabled, you can add verbosity by running
<command>LIBGL_DEBUG=verbose glxinfo</command>. This will show the
drivers, device nodes and files used by the DRI system.
</para>
<para>
To confirm that DRI2 hardware acceleration is working, you can (still in
the X terminal) run the command <command>glxinfo | egrep "(OpenGL
vendor|OpenGL renderer|OpenGL version)"</command>.
If that reports something <emphasis>other than</emphasis>
<literal>Software Rasterizer</literal> then you have working
acceleration for the user who ran the command.
</para>
<para>
If your hardware does not have any DRI2 driver available, it will use a
Software Rasterizer for Direct Rendering. In such cases, you can use a
new, LLVM-accelerated, Software Rasterizer called LLVMPipe. In order to
build LLVMPipe just make sure that <xref linkend="llvm"/> is present at
Mesa build time. Note that all decoding is done on the CPU instead of
the GPU, so the display will run slower than with hardware acceleration.
To check if you are using LLVMpipe, review the output of the glxinfo
command above. An example of the output using the Software Rasterizer
is shown below:
</para>
<screen><computeroutput>OpenGL vendor string: VMware, Inc.
OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.5, 256 bits)
OpenGL version string: 3.0 Mesa 10.4.5</computeroutput></screen>
<para>
You can also force LLVMPipe by exporting the
<envar>LIBGL_ALWAYS_SOFTWARE=1</envar> environment variable when
starting Xorg.
</para>
<para>
Again, if you have built the Mesa OpenGL demos, you can also run the test
program <command>glxgears</command>. This program brings up a window with
three gears turning. The X terminal will display how many frames were
drawn every five seconds, so this will give a rough benchmark. The window
is scalable, and the frames drawn per second is highly dependent on the
size of the window. On some hardware, <command>glxgears</command> will
run synchronized with the vertical refresh signal and the frame rate will
be approximately the same as the monitor refresh rate.
</para>
</sect2>
<sect2 role="configuration" id="hybrid-graphics" xreflabel="Hybrid Graphics">
<title>Hybrid Graphics</title>
<para>
Hybrid Graphics is still in experimental state for Linux. Xorg Developers
have developed a technology called PRIME that can be used for switching
between integrated and muxless discrete GPU at will. Automatic switching
is not possible at the moment.
</para>
<para>
In order to use PRIME for GPU switching, make sure that you are using
Linux Kernel 3.4 or later (recommended). You will need latest DRI and
DDX drivers for your hardware and <application>Xorg Server</application>
1.13 or later.
</para>
<para>
<application>Xorg Server</application> should load both GPU drivers
automaticaly. You can check that by running:
</para>
<screen><userinput>xrandr --listproviders</userinput></screen>
<para>
There should be two (or more) providers listed, for example:
</para>
<screen><computeroutput>Providers: number : 2
Provider 0: id: 0x7d cap: 0xb, Source Output, Sink Output, Sink Offload crtcs: 3 outputs: 4 associated providers: 1 name:Intel
Provider 1: id: 0x56 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 6 outputs: 1 associated providers: 1 name:radeon</computeroutput></screen>
<para>
In order to be able to run a GLX application on a discrete GPU, you will
need to run the following command, where &lt;provider&gt; is the more
powerful discrete card, and &lt;sink&gt; is the card which has a display
connected:
</para>
<screen><userinput>xrandr --setprovideroffloadsink <replaceable>&lt;provider&gt; &lt;sink&gt;</replaceable></userinput></screen>
<note>
<para>
With newer <application>Xorg</application> drivers, such as modesetting
or intel, which are DRI3 capable, the above command is no longer
necessary. It does no harm however.
</para>
</note>
<para>
Then, you will need to export the <envar>DRI_PRIME=1</envar> environment
variable each time you want the powerful GPU to be used. For example,
<screen><userinput>DRI_PRIME=1 glxinfo | egrep "(OpenGL vendor|OpenGL renderer|OpenGL version)"</userinput></screen>
will show OpenGL vendor, renderer and version for the discrete GPU.
</para>
<para>
If the last command reports same OpenGL renderer with and without
<envar>DRI_PRIME=1</envar>, you will need to check your installation.
</para>
</sect2>
<sect2 role="configuration" id='xconfig'>
<title>Setting up Xorg Devices</title>
<para>
For most hardware configurations, modern Xorg will automatically
get the server configuration correct without any user intervention. There
are, however, some cases where auto-configuration will be incorrect.
Following are some example manual configuration items that may be of use
in these instances.
</para>
<sect3 id="xinput">
<title>Setting up X Input Devices</title>
<para>
For most input devices, no additional configuration will be
necessary. This section is provided for informational purposes only.
</para>
<para>
A sample default XKB setup could look like the following (executed as
the <systemitem class="username">root</systemitem> user):
</para>
<screen role="root"><userinput>cat &gt; /etc/X11/xorg.conf.d/xkb-defaults.conf &lt;&lt; "EOF"
Section "InputClass"
Identifier "XKB Defaults"
MatchIsKeyboard "yes"
Option "XkbLayout" "fr"
Option "XkbOptions" "terminate:ctrl_alt_bksp"
EndSection
EOF</userinput></screen>
<para>
The <quote>XkbLayout</quote> line is an example for a French (AZERTY)
keyboard. Change it to your keyboard model. That line is not needed for
a QWERTY (US) keyboard.
</para>
</sect3>
<sect3 id="xdisplay">
<title>Fine Tuning Display Settings</title>
<para>
Again, with modern Xorg, little or no additional configuration is
necessary. If you should need extra options passed to your video driver,
for instance, you could use something like the following (again,
executed as the <systemitem class="username">root</systemitem> user):
</para>
<screen role="root"><userinput>cat &gt; /etc/X11/xorg.conf.d/videocard-0.conf &lt;&lt; "EOF"
Section "Device"
Identifier "Videocard0"
Driver "radeon"
VendorName "Videocard vendor"
BoardName "ATI Radeon 7500"
Option "NoAccel" "true"
EndSection
EOF</userinput></screen>
<para>
Another common setup is having multiple server layouts for use in
different environments. Though the server will automatically detect the
presence of another monitor, it may get the order incorrect:
</para>
<screen role="root"><userinput>cat &gt; /etc/X11/xorg.conf.d/server-layout.conf &lt;&lt; "EOF"
Section "ServerLayout"
Identifier "DefaultLayout"
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" LeftOf "Screen0"
Option "Xinerama"
EndSection
EOF</userinput></screen>
</sect3>
</sect2>
</sect1>