Buzzing snd_emu10kx enabled card with r206173

[Garrett Cooper]

On Mon, Apr 5, 2010 at 12:26 PM, Garrett Cooper <yanefbsd at gmail.com> wrote:
> On Mon, Apr 5, 2010 at 11:22 AM, Garrett Cooper <yanefbsd at gmail.com> 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.

Grr... it's `healed' itself again. I'll watch out for potential
catalysts to the issue in the future.
Thanks,
-Garrett