1.\" $OpenBSD: ac97.4,v 1.17 2008/08/28 13:09:02 jmc Exp $ 2.\" 3.\" Copyright (c) 1999, 2000 Constantine Sapuntzakis 4.\" 5.\" Author: Constantine Sapuntzakis <csapuntz@stanford.edu> 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. The name of the author may not be used to endorse or promote 16.\" products derived from this software without specific prior written 17.\" permission. 18.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS 19.\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 20.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE 22.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 24.\" OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 25.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 26.\" LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE 28.\" USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 29.\" DAMAGE. 30.\" 31.Dd $Mdocdate: August 28 2008 $ 32.Dt AC97 4 33.Os 34.Sh NAME 35.Nm ac97 36.Nd generic AC'97 codec driver 37.Sh DESCRIPTION 38AC'97 codecs contain the analog-to-digital (A/D), digital-to-analog 39(D/A), and mixing circuitry of many modern sound cards. 40AC'97 codecs, for the most part, do not talk to host buses like the PCI bus 41directly. 42Instead, they communicate through an interface chip, called 43the host controller. 44The Ensoniq AudioPCI 97 (see 45.Xr eap 4 ) 46is an example of such a host controller. 47.Pp 48Unlike many drivers, the 49.Nm 50driver does not appear in the configuration file. 51Instead, the driver is automatically attached by the drivers that require it. 52.Sh SEE ALSO 53.Xr auacer 4 , 54.Xr auich 4 , 55.Xr auixp 4 , 56.Xr autri 4 , 57.Xr auvia 4 , 58.Xr clcs 4 , 59.Xr clct 4 , 60.Xr eap 4 , 61.Xr emu 4 , 62.Xr esa 4 , 63.Xr fms 4 , 64.Xr maestro 4 , 65.Xr neo 4 , 66.Xr yds 4 67.Sh BUGS 68The 69.Nm 70driver does not keep track of the current user settings and instead 71relies on the hardware to do this. 72.Pp 73The 74.Nm 75driver could do more to detect mixer channels that don't work and cull 76them from the list. 77