Sound drops

Sound drops

[Hubert Figuiere]

I don't like to work in silence, so I usually play back a 
bunch of mp3 with xaudio under Linux PPC from my PowerBook.

The problem is that I get a lot of sound drops like if the machine
were "mono-tasking". I have never had this with PC hardware under Linux.

It appears that those drops occurs when doing intensive graphics like
a Netscape redrawing or a huge text scroll within an xterm. This happens
with Xpmac or XFB_Dev.

Kernel is 2.2.1 home compiled (with or without my patches), and machine 
is PowerBook 3400c with 80 MB of RAM.

My question is: Is it a known bug of the sound drivers or is it a 
hardware limitation ?

Hub
-- 
World Wide Wait: the real meaning for WWW.

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Re: Sound drops

[Hollis R Blanchard]

On Wed, 10 Mar 1999, Hubert Figuiere wrote:
> 
> I don't like to work in silence, so I usually play back a 
> bunch of mp3 with xaudio under Linux PPC from my PowerBook.

xaudio? Haven't heard of it.

> The problem is that I get a lot of sound drops like if the machine
> were "mono-tasking". I have never had this with PC hardware under Linux.
> 
> It appears that those drops occurs when doing intensive graphics like
> a Netscape redrawing or a huge text scroll within an xterm. This happens
> with Xpmac or XFB_Dev.

Try adding a buffer switch - for example, mpg123 takes -b1024 where 1024 is
the size of the buffer in K, IIRC. I don't have any idea what xaudio is, but
I think most sound playback programs have specifiable buffers.

-Hollis


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Re: Sound drops

[Michel Lanners]

On  10 Mar, this message from Hubert Figuiere echoed through cyberspace:
> I don't like to work in silence, so I usually play back a 
> bunch of mp3 with xaudio under Linux PPC from my PowerBook.
> 
> The problem is that I get a lot of sound drops like if the machine
> were "mono-tasking". I have never had this with PC hardware under Linux.
> 
> It appears that those drops occurs when doing intensive graphics like
> a Netscape redrawing or a huge text scroll within an xterm. This happens
> with Xpmac or XFB_Dev.
>
> My question is: Is it a known bug of the sound drivers or is it a 
> hardware limitation ?

IIRC, there was such a question on /. recently. You might ant to look
over there.

I would rather attribute this symptom to a problem in X, where the X
server is allowed to monopolize much of the machine for redrawing. The
fact the our current X servers (all those I tried, even Xpmac_mga
accelerated for my Matrox) eat _huge_ amounts of CPU for all blitting
operations like scrolling etc.

There seems to be work to do on the X side of things....

Michel

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Re: Sound drops

[Paul Mackerras]

Hubert Figuiere <hub@point-barre.fr> wrote:

> I don't like to work in silence, so I usually play back a 
> bunch of mp3 with xaudio under Linux PPC from my PowerBook.
> 
> The problem is that I get a lot of sound drops like if the machine
> were "mono-tasking". I have never had this with PC hardware under Linux.
> 
> It appears that those drops occurs when doing intensive graphics like
> a Netscape redrawing or a huge text scroll within an xterm. This happens
> with Xpmac or XFB_Dev.

One thing to try is `hdparm -u1 /dev/hda'.  That sets the IDE driver
to allow interrupts during transfers to/from your hard disk.  I don't
know if it will help in your particular case, but it's worth trying.

Paul.

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