Attachment 23617 Details for Bug 40609 – file.diff

[patch] file.diff

file.diff (text/plain), 1.88 KB, created by Munish on 2002-07-15 19:30:03 UTC

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Creator: Munish

Created: 2002-07-15 19:30:03 UTC

Size: 1.88 KB

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obsolete

>--- chapter.sgml	Mon Jul 15 13:43:02 2002
>+++ vchans.sgml	Mon Jul 15 14:22:44 2002
>@@ -366,6 +366,36 @@
>     </sect2>
>   </sect1>
> 
>+  <sect2>
>+    <title>Utilizing Multiple Sound Sources</title>
>+
>+    <para>It is often desirable to have multiple sources of sound that are able to
>+      play simultaneously, such as when <application>esound</application> or
>+      <application>artsd</application> don't support sharing of the sound device
>+      with a certain application.</para>
>+
>+    <para>FreeBSD lets you do this through `Virtual Sound Channels', which can be
>+      set with the &man.sysctl.8; facility. Virtual channels allow you to multiplex
>+      your sound card's playback channels by mixing sound in the kernel.</para>
>+
>+    <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; sysctl hw.snd.pcm0.vchans=4 &prompt.root;
>+      sysctl hw.snd.maxautovchans=4</screen>
>+
>+    <para><literal>hw.snd.pcm0.vchans</literal> is the number of vchans pcm0 has, 
>+      and is configurable once a device has been attached.<literal>hw.snd.maxautovchans
>+      </literal> is the number of vchans a new audio device is given when it is
>+      attached using &man.kldload.8;. Since the pcm module can be loaded independently 
>+      of the hardware drivers, <literal>hw.snd.maxautovchans</literal> can store how
>+      many vchans any devices which are attached later will be given.</para>
>+
>+    <para>If you are not using &man.devfs.5;, you will have to point your applications
>+      at <devicename>/dev/dsp0</devicename>.x, where 'x' is 0 to 3 if <literal>
>+      hw.snd.pcm.0.vchans</literal> is set to 4. On a system using devfs, the above 
>+      will automatically be allocated transparently to the user.</para>
>+
>   <sect1 id="sound-mp3">
>     <sect1info>
>       <authorgroup>

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