[alsa-devel] underruns and strange code in pcm_rate.c

[Takashi Iwai]

At Wed, 07 Nov 2007 20:16:36 +0300,
Stas Sergeev wrote:
> 
> Hello.
> 
> Takashi Iwai wrote:
> > I don't understand your description well.  Could you give a simple
> > test code to prove the bug?
> No, its not like that. I am not
> writing any prog. What I am trying
> to point out, is that _any_ program
> is affected. My whole desktop is
> pretty much "speechless" these days.
> Well, a few progs, like mplayer, are
> unaffected (I guess they do not trust
> "default" and use "hw"), but most of
> anything else is broken. (and as a
> most frequent test-case I use ogg123
> while debugging)

Well, I'm using ogg123 with dmix but it works fine.
That's why I'm wondering why you got so *many* problems.

And, to fix the problem, a test case is always helpful.

> Well, maybe its an asound.conf issue -
> I'll attach my asound.conf... attached.
> Maybe its a driver issue - I was using
> snd-pcsp before and I don't remember
> any problems. But now I do use snd-intel8x0,
> and the results are much worse.

Interesting.  I don't get such a problem with intel8x0 with the
standard alsa config with dmix (the default "default")...

Or, possibly wrapping with softvol is the problem?
In the default configuration, softvol is used only when "PCM Playback
Volume" doesn't exist.

> And this will remain so until I get an
> x86_64 port of snd-pcsp, and in a mean
> time I thought it would be a good idea
> to get working also that. :)
> Jokes aside, the difference is that
> snd-intel8x0 accepts only 48000, while
> snd-pcsp used to accept some other rate.
> I'll answer the technical questions in
> a separate e-mail. I'll try to collect
> more precise info and examples.

Thanks.


Takashi

> 
> [2 asound.conf <text/plain (7bit)>]
> # Generated by system-config-soundcard, do not edit by hand
> defaults.pcm.card 0 
> pcm.!default {
>     type plug
>     slave.pcm "svol"
> }
> 
> pcm.svol {
>     type softvol
>     slave.pcm "swmix"
>     control.name "SoftVol Playback Volume"
>     control.card 0
>     min_dB -0.1
>     max_dB 10.0
> }
> 
> pcm.swmix {
>     type dmix
>     ipc_key 1111
>     slave.pcm "hw:0,0"
>     slave.rate 48000
> }