sound problem

Sepherosa Ziehau sepherosa at
Mon Aug 14 02:33:15 PDT 2006

On 8/13/06, Thomas Nikolajsen <thomas.nikolajsen at xxxxxxx> wrote:
Matthew Dillon <dillon at xxxxxxxxxxxxxxxxxxxx> wrote:
> :Playing sound using pcm(4)/snd(4) gives bad quality: hiss
> and hops, like sound isn't playing for very short time
> periods.
Problem is a scratz every 10 seconds;
this was easier to hear with 440Hz sinus vs music.
> :
> :This is experienced:
> : - not having SMP in kernel config (eg GENERIC)
Ie. no problem when using SMP;
but problem is still heard having SMP without APIC_IO.
> : - from dfly-1.5 26th December '05 (24th is ok using
> kernels from chlamydia);
> :including HEAD.
> :
> :dfly-1.4 is ok, including 1.4.4.
> :
> :Using audio/mpg123 for MP3, 'cp test.raw /dev/dspW' or
> pcmplay for decoded sound.
> :Buffering audio data with mpg123 -b doesn't sound like
> making any difference.
> :
> :CPU load doesn't sound like making any difference.
> :Problem experienced on several systems, using snd_via8233
> and snd_ich.
I was wrong; only one pc experienced problem.
(other systems has bad speakers)
> :
> :No X11 used.
> :
> : -thomas
>     Hmm.  That's quite odd.  There aren't any significant
> source code changes
>     bewteen the 24th and 26th of December (I diff'd the 23rd
> and 27th to be
>     conservative).
>                                       -Matt
>                                       Matthew Dillon
>                                       <dillon at xxxxxxxxxxxxx>
It turns out problem is irq sharing: pcm0/re0 (too any NICs in test box).

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