doc/install.xml: Describe comedi_num_legacy_minors.

Add some info to the Install section about reserving devices for manual
configuration using the comedi_num_legacy_minors module parameter.

diff --git a/doc/install.xml b/doc/install.xml
index 4c63d79b10a520f8691c5c1da7750c013841b2f2..2ceb49856df4aa3fb3451eecdb946cd968832e70 100644 (file)
--- a/doc/install.xml
+++ b/doc/install.xml
@@ -39,6 +39,42 @@ Usually these devices belong to the group <systemitem class="groupname">iocard</
                  then the &comedi; device is ready to be used.
                </para>
 
+               <para>
+                 There are a few PCI drivers that for one reason or another
+                 do not support auto-configuration, either because there is
+                 more than one variant of a board sharing the same PCI device
+                 ID (e.g. Advantech PCI-1710 and PCI-1710HG), or because
+                 some configuration options are needed (e.g. Amplicon PCI224
+                 and PCI234) or for some other reason.  It is also possible
+                 to disable auto-configuration when loading the
+                 <systemitem>comedi</systemitem> kernel module.  In these
+                 cases devices need to be configured manually as for ISA
+                 cards. Conversely, most &comedi; drivers supplied with the
+                 kernel sources that support auto-configuration may no longer
+                 support manual configuration.
+               </para>
+
+               <para>
+                 By default, the <systemitem>comedi</systemitem> kernel module
+                 does not reserve any devices for manual configuration so
+                 manual configuration will fail.  To allow devices to be
+                 configured manually, set the
+                 <parameter>comedi_num_legacy_minors</parameter> module
+                 parameter to the number of devices to reserve for manual
+                 configuration when loading the <systemitem>comedi</systemitem>
+                 kernel module.  If using <command>modprobe</command>, this
+                 can be set automatically by editing
+                 <filename>/etc/modprobe.conf</filename> or
+                 <filename>/etc/modprobe.d/comedi.conf</filename> (depending
+                 on the system) to include the line:
+                 <screen>
+                   options comedi comedi_num_legacy_minors=4
+                 </screen>
+                 The number <literal>4</literal> in the above line may be
+                 adjusted to increase or decrease the number of devices to be
+                 reserved for manual configuration.
+               </para>
+
                <para>
                  Old ISA based cards need to be manually configured which is
                  explained here. You only need to read on here