From alsa-user-owner@alsa.jcu.cz  Fri Dec 18 22:16:56 1998
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	Fri, 18 Dec 1998 22:13:52 +0100
Date: Fri, 18 Dec 1998 22:13:52 +0100 (CET)
From: Jaroslav Kysela <perex@jcu.cz>
To: jjaeggli@iastate.edu
cc: alsa-user@alsa.jcu.cz
Subject: Re: interference from video
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On Fri, 18 Dec 1998 jjaeggli@iastate.edu wrote:

> > > Hello,
> > > 
> > > When using alsa, I have a lot of noise that comes from the display.  Moving the
> > > mouse or a window, or a program displaying rapidly changing information (like
> > > timidity's time bar), causes this noise or interference.
> > 
> > I'm not sure if we can improve driver to remove some noises. Most of
> > noises are analog type. I should say, that only digital output from
> > soundcard (which bypass analog path) can solve all computer interferences.
> > 
> > I have connected digital output from Turtle Beach Malibu (CS4237B)
> > soundcard to Sony STR-DB925 receiver and I should confirm that all
> > computer noises and start/end clicks disappear. Thus problem should be
> > somewhere in analog mixer and amplifier.
> 
>   I think that the problem here is different than the analog interference
> caused by electromagnetic interference witht the signal inside the case... I
> had a similar problem, such as resizing or zooming windows, moving things
> around the desktop.  I think that it may be because some interupt has
> priority, such as the video, but what I did to solve it (or mabye what
> caused the problem, was this line in my XF86Config file...
> 
>     #Option "pci_retry"    # faster, but problematic for ISA DMA
> 
> I disabled the pci_retry and the sounds when moving windows disapeared. 
> Actually, to be more discriptive, the "sounds" was not actually sound, but
> the sound being interupted, and so when I move a window a lot durring
> playback (such as x11amp) It acted like pitch bending, as the playback would
> slow down.

Maybe you are speaking about PCI bus locking for very long time - this
problem is described in http://alsa.jcu.cz/misc/vgakills.txt document.

Yes, this should solve "noise" problem, too. 

							Jaroslav

-----
Jaroslav Kysela <perex@jcu.cz>
Academic Computer Centre, University of South Bohemia
Branisovska 31, C. Budejovice, CZ-370 05 Czech Republic


