NV10 hdac issue

[Konstantin Belousov]

On Wed, May 23, 2012 at 09:32:48PM +0300, Alexander Motin wrote:
> On 05/23/12 01:06, Konstantin Belousov wrote:
> >I have (another) Atom motherboard from Intel, DN2800MT. Now, the problem
> >is with distorted sound. Anything is played as if some pause is inserted
> >after the next sample is finished. So I hear the proper pitch, but with
> >guggle between fragments. I am not sure how to describe it better, except
> >to say that it sounds as if buffering was not enough, for regular short
> >intervals of approx. 0.5 sec.
> >
> >I do not believe that 1.8Hhz Atoms are too slow to decode mp3 or to play 
> >wav.
> >
> >The hda controller is
> >hdac0 at pci0:0:27:0:      class=0x040300 card=0x20128086 chip=0x27d88086 
> >rev=0x02 hdr=0x00
> >codec is Realtek ALC888. The verbose dmesg from hda_snd load is at
> >http://people.freebsd.org/~kib/tom.dmesg.txt , assuming this is useful.
> >
> >I would want to get normal sound from this board, thanks in advance.
> 
> I haven't seen alike reports neither for this controller, nor for this 
> CODEC. I would try to experiment with:
> 1) disabling MSI interrupts with hint.hdac.0.msi=0
> 2) switching to polling mode without using any interrupts with 
> dev.hdac.0.polling=1
> 3) changing buffer size with hw.snd.latency
> 4) changing playback format (or vchans format it it is used)
> 5) setting sysctl hw.snd.verbose=2 and checking for application level 
> underruns with `cat /dev/sndstat`.

Thank you, setting hw.snd.latency to 10 fixed the issue. Still, I do not
understand why default settings for the driver are not enough for the
machine.
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