audible clicks with ICH4 AC'97

[martinko]

Hallo Ariff and others,

After 2 years or something I've finally reinstalled broken Windows on my 
laptop and I can confirm now that we have an issue with sound (driver). 
  /I feared there's something with my HW./

The thing is that playing music on FreeBSD reminds me of old tapes while 
listening to the same files on Windows produces no acoustic clicks etc 
at all.  (Well, I cannot hear these clicks during music but throughout 
low volume passages they are quite audible.)

I hope something can be done about it..

With best regards,

Martin

--

$ uname -a
FreeBSD mb-aw1n-bsd 6.2-STABLE FreeBSD 6.2-STABLE #0: Tue May 29 
22:23:01 CEST 2007     root at mb-aw1n-bsd:/usr/obj/usr/src/sys/MB-AW1N  i386

$ pciconf -lv | grep -B 4 audio
pcm0 at pci0:31:5: class=0x040100 card=0x18431043 chip=0x24c58086 rev=0x03 
hdr=0x00
     vendor     = 'Intel Corporation'
     device     = '82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio 
Controller'
     class      = multimedia
     subclass   = audio

# cat /dev/sndstat
FreeBSD Audio Driver (newpcm)
Installed devices:
pcm0: <Intel ICH4 (82801DB)> at io 0xffaff800, 0xffaff400 irq 5 bufsz 
16384 kld snd_ich (1p/1r/2v channels duplex default)
         [pcm0:play:0:dsp0.0]: spd 48000, fmt 0x10000010, flags 
0x00103000, 0x00000040
         interrupts 52787, underruns 0, ready 0 
[b:2048/1024/2|bs:2048/1024/2]
         {userland} -> feeder_vchan_s16(0x10000010) -> 
feeder_volume_s16(0x10000010) -> {hardware}
         [pcm0:record:0:dsp0.1]: spd 0, fmt 0x00000000/0x00000008, flags 
0x00000000, 0x00000000
         interrupts 0, overruns 0, hfree 16384, sfree 0 
[b:16384/8192/2|bs:0/0/0]
         {hardware} -> feeder_root(0x00000000) -> {userland}
         pcm0:play:0:dsp0.0[pcm0:virtual:0:dsp0.2]: spd 8000/48000, fmt 
0x00000008/0x10000010, flags 0x10000000, 0x00000010
         interrupts 0, underruns 0, ready 0 [b:0/1024/0|bs:131072/128/1024]
         {userland} -> feeder_root(0x00000008) -> 
feeder_u8toulaw(0x00000008 -> 0x00000001) -> 
feeder_ulawtos16le(0x00000001 -> 0x00000010) -> 
feeder_monotostereo16(0x00000010 -> 0x10000010) -> feeder_rate(8000 -> 
48000) -> {hardware}
         pcm0:play:0:dsp0.0[pcm0:virtual:1:dsp0.3]: spd 22050/48000, fmt 
0x10000010, flags 0x10000000, 0x00000010
         interrupts 0, underruns 0, ready 0 [b:0/1024/0|bs:131072/2048/64]
         {userland} -> feeder_root(0x10000010) -> feeder_rate(22050 -> 
48000) -> {hardware}

File Versions:
$FreeBSD: src/sys/dev/sound/pci/ich.c,v 1.53.2.11 2007/05/28 21:07:41 
ariff Exp $
$FreeBSD: src/sys/dev/sound/isa/sndbuf_dma.c,v 1.3 2005/01/06 01:43:17 
imp Exp $
$FreeBSD: src/sys/dev/sound/pcm/vchan.c,v 1.17.2.5 2007/02/04 06:17:14 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/sound.c,v 1.93.2.4 2007/05/28 21:18:06 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/sndstat.c,v 1.20.2.2 2005/12/30 19:55:54 
netchild Exp $
$FreeBSD: src/sys/dev/sound/pcm/mixer.c,v 1.43.2.5 2007/05/13 20:53:39 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder_volume.c,v 1.2.2.1 2005/12/30 
19:55:54 netchild Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder_rate.c,v 1.11.2.2 2006/01/29 
02:27:28 ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder_fmt.c,v 1.14.2.2 2006/01/29 
02:27:28 ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/feeder.c,v 1.33.2.3 2006/03/07 15:51:19 
jhb Exp $
$FreeBSD: src/sys/dev/sound/pcm/fake.c,v 1.14.2.1 2005/12/30 19:55:54 
netchild Exp $
$FreeBSD: src/sys/dev/sound/pcm/dsp.c,v 1.80.2.6 2006/04/04 17:43:48 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/channel.c,v 1.99.2.5 2007/05/13 20:53:39 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/buffer.c,v 1.25.2.3 2007/04/26 08:21:43 
ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/ac97_patch.c,v 1.3.2.2 2007/04/26 
08:30:52 ariff Exp $
$FreeBSD: src/sys/dev/sound/pcm/ac97.c,v 1.53.2.5 2007/05/13 20:53:39 
ariff Exp $

# sysctl hw.snd dev.pcm
hw.snd.report_soft_formats: 1
hw.snd.targetirqrate: 32
hw.snd.verbose: 3
hw.snd.maxautovchans: 4
hw.snd.unit: 0
hw.snd.pcm0.buffersize: 16384
hw.snd.pcm0.vchans: 2
hw.snd.pcm0.ac97rate: 48000
dev.pcm.0.%desc: Intel ICH4 (82801DB)
dev.pcm.0.%driver: pcm
dev.pcm.0.%location: slot=31 function=5 handle=\_SB_.PCI0.AUDI
dev.pcm.0.%pnpinfo: vendor=0x8086 device=0x24c5 subvendor=0x1043 
subdevice=0x1843 class=0x040100
dev.pcm.0.%parent: pci0
dev.pcm.0.wake: 0

$ /usr/sbin/mixer
Mixer vol      is currently set to  75:75
Mixer pcm      is currently set to  10:10
Mixer speaker  is currently set to  25:25
Mixer line     is currently set to  75:75
Mixer mic      is currently set to   0:0
Mixer cd       is currently set to  75:75
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  75:75
Mixer phin     is currently set to   0:0
Mixer phout    is currently set to   0:0
Mixer video    is currently set to  75:75
Recording source: mic