Handbook update: HorizSync and VertRefresh

Warren Block wblock at wonkity.com
Mon Jul 2 23:08:00 UTC 2012


The X11 configuration chapter of the Handbook has some very old 
information which is confusing users.  Manually setting HorizSync and 
VertRefresh has been mostly useless for many years, and should be 
deemphasized.

This patch does that.  Instead of saying the sync frequencies must 
always be entered, it adds some information about autodetection and 
points out that almost all monitors support it.  Also added is a note 
not to guess about sync frequencies.  On the CRT monitors where it 
matters, it can matter a lot.  Some of those monitors might still be 
functional.

Feedback welcome.  If there aren't any loud screams of outrage, squawks 
of offense, or mere bacaws of disgust, I'll commit it in a couple of 
days.
-------------- next part --------------
Index: doc/en_US.ISO8859-1/books/handbook/x11/chapter.sgml
===================================================================
--- doc/en_US.ISO8859-1/books/handbook/x11/chapter.sgml	(revision 39167)
+++ doc/en_US.ISO8859-1/books/handbook/x11/chapter.sgml	(working copy)
@@ -364,36 +364,47 @@
     <sect2>
       <title>Before Starting</title>
 
-      <para>Before configuration of X11
-	the following information about the target system is needed:</para>
+      <para>In most cases, X11 is self-configuring.  Those with older
+	or unusual equipment may find it helpful to gather some
+	hardware information before beginning configuration.</para>
 
       <itemizedlist>
-	<listitem><para>Monitor specifications</para></listitem>
-	<listitem><para>Video Adapter chipset</para></listitem>
-	<listitem><para>Video Adapter memory</para></listitem>
+	<listitem><para>Monitor sync frequencies</para></listitem>
+	<listitem><para>Video card chipset</para></listitem>
+	<listitem><para>Video card memory</para></listitem>
       </itemizedlist>
 
-      <indexterm><primary>horizontal scan rate</primary></indexterm>
-      <indexterm><primary>vertical scan rate</primary></indexterm>
+      <indexterm>
+	<primary>horizontal sync frequency</primary>
+      </indexterm>
+      <indexterm>
+	<primary>horizontal scan rate</primary>
+	<see>horizontal sync frequency</see>
+      </indexterm>
+      <indexterm><primary>refresh rate</primary></indexterm>
+      <indexterm>
+	<primary>vertical sync frequency</primary>
+	<see>refresh rate</see>
+      </indexterm>
+      <indexterm>
+	<primary>vertical scan rate</primary>
+	<see>refresh rate</see>
+      </indexterm>
 
-      <para>The specifications for the monitor are used by
-	X11 to determine the resolution and
-	refresh rate to run at.  These specifications can usually be
-	obtained from the documentation that came with the monitor or from
-	the manufacturer's website.  There are two ranges of numbers that
-	are needed, the horizontal scan rate and the vertical synchronization
-	rate.</para>
+      <para>Screen resolution and refresh rate are determined by the
+	monitor's horizontal sync and vertical sync frequencies.
+	Almost all monitors support autodetection of these values
+	electronically.  A few monitors do not provide these values,
+	and the specifications must be determined from the printed
+	documentation or manufacturer web site.</para>
 
-      <para>The video adapter's chipset defines what driver module
-	X11 uses to talk to the graphics
-	hardware.  With most chipsets, this can be automatically
-	determined, but it is still useful to know in case the automatic
-	detection does not work correctly.</para>
+      <para>The video card's chipset is also autodetected, and used
+	to select the proper video driver.  It is beneficial for the
+	user to be aware of which chipset is installed for when
+	autodetection does not provide the desired result.</para>
 
-      <para>Video memory on the graphic adapter determines the
-	resolution and color depth which the system can run at.  This is
-	important to know so the user knows the limitations of the
-	system.</para>
+      <para>Memory available on the video card determines the maximum
+	resolution and color depth which can be displayed.</para>
     </sect2>
 
     <sect2>
@@ -584,12 +595,12 @@
 
       <indexterm><primary>X11 tuning</primary></indexterm>
 
-      <para>Next, tune the <filename>xorg.conf.new</filename>
-	configuration file to taste.  Open the file in a text editor such
-	as &man.emacs.1; or &man.ee.1;.  First, add the
-	frequencies for the target system's monitor.  These are usually
-	expressed as a horizontal and vertical synchronization rate.  These
-	values are added to the <filename>xorg.conf.new</filename> file
+      <para>The <filename>xorg.conf.new</filename>
+	configuration file may now be tuned to taste.  Open the file in a text editor such
+	as &man.emacs.1; or &man.ee.1;.  If the monitor is an older
+	or unusual model that does not support autodetection of
+	sync frequencies, those settings can
+	be added to <filename>xorg.conf.new</filename>
 	under the <literal>"Monitor"</literal> section:</para>
 
       <programlisting>Section "Monitor"
@@ -600,14 +611,11 @@
 	VertRefresh  48-120
 EndSection</programlisting>
 
-      <para>The <literal>HorizSync</literal> and
-	<literal>VertRefresh</literal> keywords may be missing in the
-	configuration file.  If they are, they need to be added, with
-	the correct horizontal synchronization rate placed after the
-	<literal>HorizSync</literal> keyword and the vertical
-	synchronization rate after the <literal>VertRefresh</literal>
-	keyword.  In the example above the target monitor's rates were
-	entered.</para>
+      <para>Most monitors support sync frequency autodetection, making
+	manual entry of these values unnecessary.  When a monitor does
+	not support autodetection, it is important to set these
+	frequencies only to the values provided by the manufacturer.
+	Do not guess.</para>
 
       <para>X allows DPMS (Energy Star) features to be used with capable
 	monitors. The &man.xset.1; program controls the time-outs and can force
@@ -684,7 +692,7 @@
       <title>Advanced Configuration Topics</title>
 
       <sect3>
-	<title>Configuration with &intel; i810 Graphics Chipsets</title>
+	<title>Configuration with &intel; <literal>i810</literal> Graphics Chipsets</title>
 
 	<indexterm><primary>Intel i810 graphic chipset</primary></indexterm>
 


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