[PlanetCCRMA] network support in the low lat. kernel

[Fernando Pablo Lopez-Lezcano]

>  >So it would seem you were having problems with name
>  >resolution. To confirm that you could try pinging to a numerical >address
>  >instead of the computer's name. If you can ping then the problem is >name
>  >resolution (ie: translation of names to ip addresses). Are you getting
>  >your ip address through dhcp? From where? Check the contents of
>  >/etc/resolv.conf, it should contain the name of the name server you
>  >should be using.
> 
> I do use dhcp, so you're probably right.  I'll look into the resolv.conf 

That should be set up by the dhcp software. If it is empty (I would not
know why) then that's the problem. You could look at /var/log/messages
and see if you have any error messages from dhcpd. 

> .  I am just a bit surprised that this would change after installing 
> your kernel, i didn't get the impression that it would change any of 
> those settings.  Perhaps I messed it up myself?

Yes, the kernel install should not have changed anything with regards to
network configuration. And it cannot be a problem with the network
interface driver being broken in the new kernel because you are able to
do other things on the network. It just looks like name resolution is
not working. One way to check is to see if you can ping a host by its ip
address (number instead of name). 

>  >>programs (audacity in particular) >>will
>  >> occasionally while playing back sound make a loud "scribbly" noise 
>  >> and hang for a while.  Why is this?
> 
>  >It would seem you are describing an underrun but I can't be sure. The
>  >system is not able to deliver samples to the soundcard in time and >there
>  >is a gap in the sound, most of the time accompained with clicks at the
>  >beginning and end of the gap. Check that you have low latency turned on
>  >(see instructions in the Planet CCRMA pages on optimizing for low
>  >latency) and that the disk is optimized (at least using dma).
> 
> yup, pretty sure I did that, but I could have messed up I suppose.
> 
>  >When you
>  >say "hangs for a while", how long is that? A fraction of a second?
> 
> Not really.  In audacity, while playing back a wav-file, there will be a 
> screech for about half - quarter of a second, and then nothing (the 
> cursor doesn't move) but the play button is still pressed down.  Then if 
> I press the stop button, it will remain pressed together with the play 
> button for perhaps 5-7 seconds, during which time the program will be 
> completely unresponsive.  Then it just returns to normal, the cursor at 
> the beginning of the waveform, the program responsive and ready to try 
> again.

That sounds definitely worse than an underrun :-( If you have a 44.1k
stereo wav file you could try using aplay just to see if native alsa
playback is working fine (audacity uses oss emulation). 

> In soundtracker playback will occasionally stop after about half a 
> second of playback and the quick scribbly-screech.  Restarting the 
> playback works fine, but the same thing will happen for about 4-5 tries 
> then it'll work like a charm all of the sudden.  (this screech-hang 
> seems quite random)
> 
> The gnome soundrecorder sometimes screeches and hangs (has to be killed 
> with xkill) after playing about 4-5 seconds.

Yuck. It would seem there is a problem with the alsa driver in your
configuration (or see below, it could be you have too little ram and the
machine is swapping all the time). 

> Anyway, like you say, ther IS the possibility that I forgot to turn on 
> the low latency, so I suppose

Most probably the low latency patch would not have _that_ drastic an
effect, I think. 

>  >> My setup:  fujitsu-siemens lifebook s-4510, cpu: pentium II 450 MHz, 
>  >>128 sdram, soundcard: intel 810 ac97 (I know - its embarrasing), RedHat 9
> 
>  >Sounds ok to me.
> 
> Good to know that it's not entirely out of the question for me to be 
> messing with the ccrma packages! Out of curiosity do you think that once 
> you get the rpms for ardour, I would be able to use that on my hardware? 

Well, it depends on whether you can get clean audio from it. The memory
looks a little scarce to me, 128M is on the edge these days  (I'd use a
minimum of 256M). It depends on how many applications you have open at
the same time and what Window Manager or Desktop you are using. With
128M you don't have much margin and the machine will start swapping.
When that happens a lot of stuff slows down to the speed of the disk,
which is quite slow compared to memory. 

>   I would probably be recording vocals or instrumental solos to 
> simultaneous playback of at most three or four tracks and mixing it. 
> (sort of what I was hoping to do in audacity).

-- Fernando