Buzzing snd_emu10kx enabled card with r206173

[Garrett Cooper]

Hi,
    When I first installed FreeBSD on this machine, I had a heck of a
time getting the soundcard's PCM channel to function properly. It
would buzz incessantly when I played any audio on it; I disabled the
onboard snd_hda enabled audio and things magically worked, until
today. After a kernel upgrade and a few warm boots, I'm back to where
I started from -- the PCM channel buzzes whenever I play audio;
line-in works perfectly fine however. I'm not seeing anything out of
the ordinary in commits over the past couple of weeks for the pcm
pieces (the last successful kernel I used was 2~3 weeks old).
    Are there any device_printf's I should add or a debug procedure
that you recommend I do to triage the situation?
Thanks,
-Garrett

# uname -a
FreeBSD bayonetta.local 9.0-CURRENT FreeBSD 9.0-CURRENT #1 r206173M:
Sun Apr  4 19:54:22 PDT 2010
root at bayonetta.local:/usr/obj/usr/src/sys/BAYONETTA  amd64
# pciconf -lv | grep -A 4 emu
emu10kx0 at pci0:8:0:0:	class=0x040100 card=0x10211102 chip=0x00081102
rev=0x00 hdr=0x00
    vendor     = 'Creative Technology LTD.'
    device     = 'sound blaster Audigy 2 (ca0108)'
    class      = multimedia
    subclass   = audio
# dmesg | grep 'irq 16'
uhci0: <Intel 82801JI (ICH10) USB controller USB-D> port 0xa800-0xa81f
irq 16 at device 26.0 on pci0
pcib7: <ACPI PCI-PCI bridge> irq 16 at device 28.1 on pci0
emu10kx0: <Creative Audigy 4 [SB0610]> port 0xec00-0xec3f irq 16 at
device 0.0 on pci8
# dmesg | grep 'pcm'
pcm0: <EMU10Kx DSP front PCM interface> on emu10kx0
pcm0: <SigmaTel STAC9750/51 AC97 Codec>
pcm1: <EMU10Kx DSP rear PCM interface> on emu10kx0
pcm2: <EMU10Kx DSP center PCM interface> on emu10kx0
pcm3: <EMU10Kx DSP subwoofer PCM interface> on emu10kx0
pcm4: <EMU10Kx DSP side PCM interface> on emu10kx0