Problem on snd_ich module

[Daan Vreeken [PA4DAN]]

Hi Angka,

On Wednesday 22 February 2006 09:58, Angka H. K. wrote:
> My card is recognized as Intel ICH 6 and using conexant ac 97 codec. Here
> is my pciconf -lv output
>
> pcm0 at pci0:30:2: class=0x040100 card=0x3080103c chip=0x266e8086 rev=0x03
> hdr=0x00 vendor   = 'Intel Corporation'
>     device   = '82801FB/FR/FW/FRW AC '97 Audio Controller'
>     class    = multimedia
>     subclass = audio
>
> My problem is:
> When module snd_ich loaded my system becoming very slow.
>
> >From the "top" command i get the"CPU states:" for the interrupt is high,
> > up to 80%

I have had the same problem last year with my laptop and the snd_ich driver. 
"vmstat -i" showed about 30.000 interrupts per second for pcm0. I fixed it by 
changing :
ich_wr(sc, ICH_REG_GLOB_CNT, ICH_GLOB_CTL_COLD | ICH_GLOB_CTL_PRES, 4);
into :
ich_wr(sc, ICH_REG_GLOB_CNT, ICH_GLOB_CTL_COLD, 4);
in the ich_init() function in src/sys/dev/sound/pci/ich.c

I'm not an ICH-expert and I don't have the datasheets, so I don't know exactly 
what that bit toggles, but turning it off helped in my case without any loss 
of functionality.

grtz,
Daan