Upgrade from 5.3 -> 5.4 release makes 5.1 sound from OSS jerky?

[maarfree]

Hello, 

I upgraded last night from FreeBSD 5.3 to 5.4 Release. I use OSS for my
sound. Before the upgrade 6 channel sound (with mplayer) was perfect.
Now it is jerky, when I comment out channels=6 in mplayer.conf sound is
good (but not surround offcourse!).

Please see below more info of my system onfiguration.

Thanks,

Maarten

PS This question is posted to opensound forum as well.

maarten# cat /dev/sndstat 
OSS/FreeBSD 3.99.2c (C) 4Front Technologies 1996-2004 

License serial number: E00000008 
**** UNREGISTERED VERSION **** 

Drivers: ALL 
License will expire after: 06/2005 


*** Unregistered version *** 

Build: 200504131459 
Kernel: FreeBSD 5.4-RELEASE #0: Mon May 9 23:32:53 CEST 2005 
maarten at maarten.lan:/usr/obj/usr/src/sys/MAARTEN2 


Card config: 
VIA 8233 AC97 audio controller at 0xb000 irq 22 
OSS Virtual Mixer Pro 
IMUX Input Multiplexer 
MIDI loopback driver 

Audio devices: 
0: VT8237 (DUPLEX,GRC3) 
Opened by 20295/mplayer @ 48000/48000 Hz 
1: VT8237 (shadow) (DUPLEX,GRC3) 
2: OSS Virtual Mixer v2.5 Playback CH #0 (GRC3) 
3: OSS Virtual Mixer v2.5 Playback CH #1 (GRC3) 
4: OSS Virtual Mixer v2.5 Playback CH #2 (GRC3) 
5: OSS Virtual Mixer v2.5 Playback CH #3 (GRC3) 
6: OSS Virtual Mixer v2.5 Playback CH #4 (GRC3) 
7: OSS Virtual Mixer v2.5 Playback CH #5 (GRC3) 
8: OSS Virtual Mixer v2.5 Playback CH #6 (GRC3) 
9: OSS Virtual Mixer v2.5 Playback CH #7 (GRC3) 
10: IMux0 CH #0 (GRC3) 
11: IMux0 CH #1 (GRC3) 
12: IMux0 CH #2 (GRC3) 
13: IMux0 CH #3 (GRC3) 
14: IMux0 CH #4 (GRC3) 

Synth devices: 
0: OSS Virtual Synth v2.5 

Midi devices: 
0: MIDI loopback 
1: MIDI loopback server side 

Mixers: 
0: VT8237 (ALC655) 
1: Virtual Mixer 
2: IMUX Control panel 

History: 
dsp0: pid 20295 cmd 'mplayer' OUT 
dsp0: pid 20295 cmd 'mplayer' OUT 
dsp0: pid 20295 cmd 'mplayer' OUT 
dsp0: pid 20295 cmd 'mplayer' OUT 
dsp0: pid 20295 cmd 'mplayer' OUT 

=========================================== 
maarten# less /usr/lib/oss/logs/soundon.log 
Starting OSS/FreeBSD 3.99.2c Tue May 10 20:29:27 CEST 2005 
8:29PM up 6 mins, 2 users, load averages: 0.12, 0.27, 0.16 
======= config ===== 
# Use soundconf to edit this file. 
/SECUREAUDIO OFF 
/PCIIRQ 6 
/IRQEXCLUDE 3 4 
/DMAEXCLUDE 2 
-PCI30591106 #VIA VT8233 AC97 audio 
VIA8233 ON 
-softmix #4Front Tech. Virtual Mixer Pro 
/CONTROL SOFTSYN parm1=6 
SOFTMIX ON 
-imux #4Front Technologies Input Multiplexer (IMUX) 
IMUX ON 
-midiloop #4Front Technologies Loopback MIDI device 
MIDILOOP ON 
====== pnpres.dat ======== 
==================== 
OSS/FreeBSD 3.99.2c (C) 4Front Technologies 1996-2004 

License serial number: E00000008 
**** UNREGISTERED VERSION **** 
/usr/lib/oss/logs/soundon.log 


============================================ 


maarten# less /usr/lib/oss/logs/osstest.log 

*** Scanning sound adapter #-1 *** 
/dev/dsp0 VT8237 (adapter0, subdev0) 
- Performing audio playback test... 
Performing left channel test on /dev/dsp0 
Test completed OK 
Performing right channel test on /dev/dsp0 
Test completed OK 
Performing stereo test on /dev/dsp0 
Test completed OK. 
Sample rate was 47980.00 Hz (-0.04%) 

/dev/dsp1 VT8237 (shadow) (adapter0, subdev1) 
- Skipping device (card already tested) 

*** Scanning sound adapter #0 *** 
/dev/dsp2 OSS Virtual Mixer v2.5 Playback CH #0 (adapter4, subdev0) 
- Skipping virtual device (use -V to force test) 

*** Scanning sound adapter #0 *** 
/dev/dsp3 OSS Virtual Mixer v2.5 Playback CH #1 (adapter4, subdev1) 
- Skipping virtual device (use -V to force test)


=====================
maarten# uname -a
FreeBSD maarten.lan 5.4-RELEASE FreeBSD 5.4-RELEASE #0: Mon May  9
23:32:53 CEST 2005     maarten at maarten.lan:/usr/obj/usr/src/sys/MAARTEN2
i386