docs/155264: [handbook] Extend "7.2.2.1 Common Problems" with hw.snd.default_unit=n

[Niclas Zeising]

The following reply was made to PR docs/155264; it has been noted by GNATS.

From: Niclas Zeising <niclas.zeising at gmail.com>
To: bug-followup at FreeBSD.org, martin.ziegler at ziegi.ch
Cc:  
Subject: Re: docs/155264: [handbook] Extend "7.2.2.1 Common Problems" with
 hw.snd.default_unit=n
Date: Mon, 23 May 2011 15:58:18 +0200

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 Hi!
 Here is a patch to add a section about this to 7.2.2.1.
 Regards!
 -- 
 Niclas
 
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 Index: chapter.sgml
 ===================================================================
 RCS file: /home/ncvs/doc/en_US.ISO8859-1/books/handbook/multimedia/chapter.sgml,v
 retrieving revision 1.141
 diff -u -d -r1.141 chapter.sgml
 --- chapter.sgml	3 Mar 2011 16:21:59 -0000	1.141
 +++ chapter.sgml	23 May 2011 13:29:32 -0000
 @@ -353,6 +353,38 @@
            </tbody>
          </tgroup>
        </informaltable>
 +      <para>Another issue is that modern graphics cards often comes with their
 +	own sound driver, for use with <acronym>HDMI</acronym> and similar. This
 +	sound device will sometimes be enumerated before the actual soundcard
 +	and the soundcard will subsequently not be used as the default playback
 +	device.  To check if this is the case, run
 +	<application>dmesg</application> and look for <literal>pcm</literal>.
 +	The output looks something like this:</para>
 +	<programlisting>...
 +hdac0: HDA Driver Revision: 20100226_0142
 +hdac1: HDA Driver Revision: 20100226_0142
 +hdac0: HDA Codec #0: NVidia (Unknown)
 +hdac0: HDA Codec #1: NVidia (Unknown)
 +hdac0: HDA Codec #2: NVidia (Unknown)
 +hdac0: HDA Codec #3: NVidia (Unknown)
 +pcm0: <HDA NVidia (Unknown) PCM #0 DisplayPort> at cad 0 nid 1 on hdac0
 +pcm1: <HDA NVidia (Unknown) PCM #0 DisplayPort> at cad 1 nid 1 on hdac0
 +pcm2: <HDA NVidia (Unknown) PCM #0 DisplayPort> at cad 2 nid 1 on hdac0
 +pcm3: <HDA NVidia (Unknown) PCM #0 DisplayPort> at cad 3 nid 1 on hdac0
 +hdac1: HDA Codec #2: Realtek ALC889
 +pcm4: <HDA Realtek ALC889 PCM #0 Analog> at cad 2 nid 1 on hdac1
 +pcm5: <HDA Realtek ALC889 PCM #1 Analog> at cad 2 nid 1 on hdac1
 +pcm6: <HDA Realtek ALC889 PCM #2 Digital> at cad 2 nid 1 on hdac1
 +pcm7: <HDA Realtek ALC889 PCM #3 Digital> at cad 2 nid 1 on hdac1
 +...</programlisting>
 +      <para> Here the graphics card (<literal>NVidia</literal>) has been
 +	enumerated before the sound card (<literal>Realtek ALC889</literal>).
 +	To use the sound card as default playback device, change
 +	<literal>hw.snd.default_unit</literal> to the unit that should be used
 +	for playback, using
 +	<screen>&prompt.root; <userinput>sysctl hw.snd.default_unit=n</userinput></screen>
 +	where <literal>n</literal> is the number of the sound device to use, in
 +	this example <literal>4</literal>.</para>
      </sect3>
    </sect2>
  
 
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