i386/113101: Fix (enable) phone out for laptops with ALC655.

[Konrad]

>Number:         113101
>Category:       i386
>Synopsis:       Fix (enable) phone out for laptops with ALC655.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 28 20:10:03 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     Konrad
>Release:        7.0-CURRENT
>Organization:
Gdansk University of Technology
>Environment:
FreeBSD predator.ether.net 7.0-CURRENT FreeBSD 7.0-CURRENT #0: Tue May  8 13:49:52 CEST 2007     versus at predator.ether.net:/usr/src/sys/i386/compile/VERSUS  i386
>Description:
For a few months I was unable to use my laptop with external headphones.
Today I tried ALSA under Knoppix, and saw interesting switch in alsamixer named front duplication or something, which made my headphones output sound.
Then I downloaded ALC655 spec and found, that by default surround out is enabled in bit 0 of 0x6a reg, so the signal only does to front speakers, and headphones apparently aren't front speakers. :) In the sheet it's called:
S-OUT is duplicated output of LINE-OUT.
>How-To-Repeat:
Install FreeBSD on Amilo Pro V2055, start xmms and connect headphones, or start mplayer in full screen (after patching the OpenChrome driver like I did), and connect your laptop to a sound system, and try to hear something. :) 
>Fix:
--- old.c       Mon May 28 21:47:55 2007
+++ ac97_patch.c        Mon May 28 21:49:59 2007
@@ -94,4 +94,12 @@
        default:
                break;
        }
+
+        /*
+         * Amilo Pro V2055 with ALC655 has phone out by default
+         * disabled (surround on), leaving us only with internal speakers. This
+         * should really go to mixer. We write the Data Flow Control reg.
+         */
+        ac97_wrcd(codec, 0x6a, ac97_rdcd(codec, 0x6a) | 1);
+
 }


>Release-Note:
>Audit-Trail:
>Unformatted: