[LAU] Re: Pops and clicks but no xruns

[James Stone]

On Sun, Apr 08, 2007 at 01:38:34PM +0200, Karl Hammar wrote:
> Andrew Burgess <aab at cichlid.com>:
> > Paul Davis wrote:
> > >> What could cause clicks without xruns? I'm baffled.
> > >PCI bus hogging, for one thing. consider running a script like this
> ...
> > Here one that works automatically for all multimedia devices:
> > # find multimedia devices
> > pcis=$(lspci -v | grep Multimedia | awk '{ print $1; }')
> > if test -z "$pcis"; then
> >   echo WARNING: no multimedia devices found on pci bus
> > else
> >   for p in $pcis; do
> >     echo set maximum latency timer for $p
> >     setpci -s $p latency_timer=ff
> >   done
> > fi
> 
> It does not work for me:
> 
>   $ lspci  | grep Multi | head -1 | cut -b-75
>   0000:00:05.0 Multimedia audio controller: nVidia Corporation nForce MultiMe
>   $ setpci -s 0000:00:05.0 latency_timer
>   lspci: -s: Invalid slot number
>   $ setpci -s 00:05.0 latency_timer
>   00
> 
> I have to remove the first 0000: from lspci, as in:
> 
>   $ cat /usr/local/sbin/pci.set.audio
>   #!/bin/sh
> 
>   val=${1:-ff}
>   # find multimedia devices
>   pcis=$( lspci -n | grep ' 0401: ' | cut -f1 -d\  | cut -f2- -d: )
>   if test -z "$pcis"; then
>     echo WARNING: no multimedia devices found on pci bus
>   else
>     for p in $pcis; do
>       lspci -s $p
>       echo -en \\tmaximum latency timer:\ 
>       setpci -s $p latency_timer | tr -s ' \n' ' '
>       setpci -s $p latency_timer=$val > /dev/null
>       echo -n '-> '
>       setpci -s $p latency_timer
>     done
>   fi
>   $
>

I am slightly confused. Is it necessary to increase the latency
timer for a pci sound card? This seems slightly
counter-intuitive. Wouldn't this reduce the performance of the
sound system through that card?

The only thing the above script changes on my system is the
latency of the SB Live.

James