[snd_hda] Choppiness under high cpu - STABLE

[Ariff Abdullah]

On Tue, 29 May 2007 13:41:58 +1000
Norberto Meijome <freebsd at meijome.net> wrote:
> Hi guys,
> Hi Ariff :)
> 
> For a month or so I've been using your binary blob,
> sndkld_releng6_i386_lowlatency_20070426.tar.gz . It worked great, (
> and so did previous releases - thanks so much!)
> 
> ( date in filename seems strange, as all the files are dated between
> 4th  and 7th of May 07)
> 
> My sound card is :
> pcm0 at pci0:27:0: class=0x040300 card=0x05b71014 chip=0x26688086
> rev=0x03 hdr=0x00
>     vendor     = 'Intel Corporation'
>     device     = '82801FB/FR/FW/FRW Intel High DefiNition Audio
>     Controller' class      = multimedia
> 
> It is detected in dmesg as :
> pcm0: <HDA Codec: Analog Devices AD1981HD>
> pcm0: <HDA Driver Revision: 20070505_0044>
> 
> kldstat:
>  4    1 0xc0907000 13be0    snd_hda.ko
>  5    2 0xc091b000 3dadc    sound.ko
> 
> 
> Anyway, a few days ago I upgraded my kernel + world to -STABLE:
> 
> FreeBSD ayiin.octantis.com.au 6.2-STABLE FreeBSD 6.2-STABLE #1: Sat
> May 26 12:31:11 EST 2007    
> root at ayiin.octantis.com.au:/usr/obj/usr/src/sys/AYIIN i386
> 
> which includes its own snd_hda :). Now, this version of the module
> (the one included in /usr/src, basically), outputs choppy sound when
> under high cpu load. It also seems to be doing small chirps every
> now and then (Very strange :D ).
> 
> I replaced all the s*nd*.ko from -stable with your binary files and
> it all works sweet again.
> 
> I haven't done any particular configuration , other than :
> hw.snd.maxautovchans=8
> 
> in /etc/sysctl.conf.
> 
> Is there anything I can do to help figure out what the problem is?
> 

Those binary modules are actually sources from -current + future fixes
which not easily MFCable. The specific snd_hda driver itself pretty
much simmilar, but the other part especially buffering and latency
improvements are quite different. There is no simple solution for this
except to keep using those binary modules, or appplying patch from the
"usuall" place.

Anyway, you can try adjusting buffer size
with "hint.pcm.0.buffersize" . Start with 4096, 8192, 16384, etc.. Use
either kenv(8) and reload, or slap it into /boot/device.hints and
reboot.

Hope that helps.


--
Ariff Abdullah
FreeBSD

... Recording in stereo is obviously too advanced
    and confusing for us idiot ***** users :P ........
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