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- Update outdated sysctl MIBs for vchans

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- Point user to pcm(4) manual page for more information.

Found and suggested by:	Johan Kuuse <kuuse@redantigua.com>
This commit is contained in:
Marc Fonvieille 2009-05-10 13:53:56 +00:00
parent b35c084c79
commit f7f7f95dc8
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=34250
1 changed files with 8 additions and 5 deletions
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13
en_US.ISO8859-1/books/handbook/multimedia/chapter.sgml
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@ -375,12 +375,14 @@ kld snd_ich (1p/2r/0v channels duplex default)</screen>
<para>To set the number of virtual channels, there are two sysctl
knobs which, if you are the <username>root</username> user, can
be set like this:</para>
<screen>&prompt.root; <userinput>sysctl hw.snd.pcm0.vchans=4</userinput>
<screen>&prompt.root; <userinput>sysctl dev.pcm.0.play.vchans=4</userinput>
&prompt.root; <userinput>sysctl dev.pcm.0.rec.vchans=4</userinput>
&prompt.root; <userinput>sysctl hw.snd.maxautovchans=4</userinput></screen>
<para>The above example allocates four virtual channels, which is a
practical number for everyday use. <varname>hw.snd.pcm0.vchans</varname>
is the number of virtual channels <devicename>pcm0</devicename> has, and is configurable
practical number for everyday use. Both <varname>dev.pcm.0.play.vchans=4</varname>
and <varname>dev.pcm.0.rec.vchans=4</varname>
are the number of virtual channels <devicename>pcm0</devicename> has for playback and recording, and are configurable
once a device has been attached.
<literal>hw.snd.maxautovchans</literal> is the number of virtual channels
a new audio device is given when it is attached using
@ -388,7 +390,8 @@ kld snd_ich (1p/2r/0v channels duplex default)</screen>
can be loaded independently of the hardware drivers,
<varname>hw.snd.maxautovchans</varname> can store how many
virtual channels any devices which are attached later will be
given.</para>
given. Refer to &man.pcm.4; manual page for more
information.</para>
<note>
<para>You cannot change the number of virtual channels for a
@ -400,7 +403,7 @@ kld snd_ich (1p/2r/0v channels duplex default)</screen>
your applications at
<filename>/dev/dsp0</filename>.<replaceable>x</replaceable>,
where <replaceable>x</replaceable> is 0 to 3 if
<varname>hw.snd.pcm.0.vchans</varname> is set to 4 as in the
<varname>dev.pcm.0.rec.vchans</varname> is set to 4 as in the
above example. On a system using &man.devfs.5;, the above will
automatically be allocated transparently to a program
that requests <filename>/dev/dsp0</filename>.</para>