1.\" $NetBSD: ac97.4,v 1.2 2005/06/22 04:19:09 kent Exp $ 2.\" $OpenBSD: ac97.4,v 1.12 2003/02/18 07:54:53 jmc Exp $ 3.\" 4.\" Copyright (c) 1999, 2000 Constantine Sapuntzakis 5.\" 6.\" Author: Constantine Sapuntzakis <csapuntz@stanford.edu> 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. The name of the author may not be used to endorse or promote 17.\" products derived from this software without specific prior written 18.\" permission. 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS 20.\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 21.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE 23.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 25.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 26.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 27.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 29.\" USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 30.\" DAMAGE. 31.\" 32.Dd October 7, 1999 33.Dt AC97 4 34.Os 35.Sh NAME 36.Nm ac97 37.Nd generic AC97 codec driver 38.Sh DESCRIPTION 39AC97 codecs contain the analog-to-digital (A/D), digital-to-analog 40(D/A), and mixing circuitry of many modern sound cards. 41AC97 codecs, for the most part, do not talk to host busses like the PCI bus 42directly. 43Instead, they communicate through an interface chip, called 44the host controller. 45The Ensoniq AudioPCI 97 (see 46.Xr eap 4 ) 47is an example of such a host controller. 48.Pp 49Unlike many drivers, the 50.Nm 51driver does not appear in the configuration file. 52Instead, the driver is automatically attached by the drivers that require it. 53.Sh SEE ALSO 54.Xr auacer 4 , 55.Xr auich 4 , 56.Xr auixp 4 , 57.Xr autri 4 , 58.Xr auvia 4 , 59.Xr clcs 4 , 60.Xr clct 4 , 61.Xr eap 4 , 62.Xr emuxki 4 , 63.Xr esa 4 , 64.Xr esm 4 , 65.Xr fms 4 , 66.Xr neo 4 , 67.\" .Xr repulse 4 , 68.Xr yds 4 69.Sh BUGS 70The 71.Nm 72driver does not keep track of the current user settings and instead 73relies on the hardware to do this. 74.Pp 75The 76.Nm 77driver could do more to detect mixer channels that don't work and cull 78them from the list. 79