Buzzing snd_emu10kx enabled card with r206173

Garrett Cooper yanefbsd at
Mon Apr 5 19:26:28 UTC 2010

On Mon, Apr 5, 2010 at 11:22 AM, Garrett Cooper <yanefbsd at> wrote:
> 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

Some more information:

1. snd_emu10kx and sound are both modules loaded on boot, along with
if_re, linux, and nvidia.
2. Disabling nvidia -> no change.
3. Disabling acpi -> unbootable system because many drivers can't map
interrupts without it (can't test unless I isolate the drivers and
enable them one by one -- something I'll try later on).

I'm at a loss right now... my hunch is that it's potentially a bad
interaction between the snd_emu10kx driver and another driver on the
same PCI bus (which is just the ACPI and uhci drivers), but I can't
test these claims. There are other funky things about my system that
have changed over the past couple of kernel versions, like front USB
ports could charge my iPhone, and now they don't... and the fact that
ACPI blanking via nvidia now works again... so something may have
changed on the backend, but I'm not 100% sure on what I should isolate
as the root cause, yet.


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