kern/73098: Scan rate of sound card shifts when vchans > 0 .

[Jim Durham]

>Number:         73098
>Category:       kern
>Synopsis:       Scan rate of sound card shifts when vchans  > 0 .
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Oct 25 00:10:15 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Jim Durham
>Release:        5.2.1-RELEASE
>Organization:
>Environment:
FreeBSD localhost 5.2.1-RELEASE-p9 FreeBSD 5.2.1-RELEASE-p9 #2: Mon Aug 30 17:45:57 EDT 2004  root at localhost:/usr/obj/usr/src/sys/JIMSLAPTOP  i386
   
>Description:
When you set hw.snd.pcm0.vchans greater than 0, the pitch of the played back sound changes about 8%. This is probably the difference between the native 48khz scan rate of the sound card and the 44.1khz scan rate needed to play the wav file or mp3 file.   
>How-To-Repeat:
sysctl hw.snd.pcm0.vchans=4     
>Fix:
Workaround  set sysctl hw.snd.pcm0.vchans=0.

Some time back, I discovered this about the time of 5.0 or 5.1 RELEASE and I worked with someone from the development team who apparently fixed the problem and committed the fix. However, I lost my old sent-mail file and I can't remember who it was. I just discovered recently that the problem is apparently back.      
>Release-Note:
>Audit-Trail:
>Unformatted: