snd_ich garbled audio

Dylan Alex Simon dylan at
Thu May 11 22:22:40 UTC 2006

> > > It is not totally garbled and doesn't happen all the time but it is
> > > almost like the endianess is wrong, or something similar as it only
> > > affects loud-ish sounds..
> >
> > Please reduce your mixer settings. If the problem vanishes, too high
> The mixer settings are quite low usually (pcm & vol/ogain)

I'm having the same kind of problem which started after upgrading from 6.0 to
6.1-RELEASE.  This is with an application using ports/libao-0.8.5_2 direct
through /dev/dsp0.0 for output, but a little testing with ossdsp output show
similar issues.  It's not significant distortion but there's clearly little
garbled skips.  It seems to happen more when the system's under load.  If I
play a simple pure tone with no load, the most reproducible issue is a little
skip (like a few hundred blank samples) every 30 seconds.


pcm0 at pci0:31:5: class=0x040100 card=0x80b01043 chip=0x24d58086 rev=0x02 hdr=0x00
    vendor   = 'Intel Corporation'
    device   = '82801EB/ER (ICH5/ICH5R) AC'97 Audio Controller'
    class    = multimedia
    subclass = audio

pcm0: <Intel ICH5 (82801EB)> port 0xe800-0xe8ff,0xef00-0xef3f mem 0xfe77bc00-0xfe77bdff,0xfe77b800-0xfe77b8ff irq 17 at device 31.5 on pci0
pcm0: <Analog Devices AD1980 AC97 Codec>

FreeBSD Audio Driver (newpcm)
Installed devices:
pcm0: <Intel ICH5 (82801EB)> at io 0xfe77bc00, 0xfe77b800 irq 17 bufsz 16384 kld snd_ich (1p/1r/0v channels duplex default)
        [pcm0:play:0:dsp0.0]: spd 44100, fmt 0x10000010, flags 0x00000000, 0x00000000
        interrupts 0, underruns 0, ready 0 [b:8192/4096/2|bs:131072/4096/32]
        {userland} -> feeder_root(0x10000010) -> {hardware}
        [pcm0:record:0:dsp0.1]: spd 8000, fmt 0x00000008/0x10000010, flags 0x00000000, 0x00000000
        interrupts 0, overruns 0, hfree 1024, sfree 131072 [b:1024/512/2|bs:131072/128/1024]
        {hardware} -> feeder_root(0x10000010) -> feeder_16leto8(0x10000010 -> 0x10000040) -> feeder_stereotomono8(0x10000040 -> 0x00000040) -> feeder_sign8(0x00000040 -> 0x00000008) -> {userland}

hw.snd.report_soft_formats: 1
hw.snd.targetirqrate: 32
hw.snd.verbose: 2
hw.snd.maxautovchans: 0
hw.snd.unit: 0
hw.snd.pcm0.buffersize: 16384
hw.snd.pcm0.vchans: 0
hw.snd.pcm0.ac97rate: 48000

Mixer vol      is currently set to   0:0
Mixer pcm      is currently set to  75:75
Mixer line     is currently set to   0:0
Mixer mic      is currently set to   0:0
Mixer cd       is currently set to   0:0
Mixer rec      is currently set to   0:0
Mixer igain    is currently set to   0:0
Mixer ogain    is currently set to  50:50
Mixer line1    is currently set to   0:0
Mixer phin     is currently set to   0:0
Mixer phout    is currently set to   0:0
Recording source: mic

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