[PD] Linux, Hammerfall, ALSA

[guenter geiger]

Johannes,

thanks for the feedback. this is very important for me, because I do
not have a HDSP card.
I will address the 512 blicksize issue soon, this will improve latency
figures (Should improve the behaviour of pd/ALSA in general, at least that
is what I hope for).

Will post updates to the list.

Guenter

On Thu, 20 Feb 2003, Johannes Taelman wrote:
> Hi all,
>
> I'm testing it here with my HDSP Multiface, and it seems to work fine as
> long as I use -blocksize 512 or bigger. Smaller buffers always sound
> broken. I'm using a 2.4.20 kernel with the low-latency patches and ext3
> patches. The latency via analog loopback as reported by
> pd/doc/7.stuff/tools/latency.pd is 25ms.
>
> It's better than going via jack, because a couple of underruns (caused by
> eg. dragging 100 objects in a patch) give a 'audio IO stuck' and I have to
> restart PD to get audio up again.
>
> Dragging lots of objects gives crackles, but operation is stable if I
> don't mess with the gui, even at very high CPU loads.
>
> 96kHz does not work. I guess PD is confused by the different number of
> channels @ 96kHz. Here the transcript:
>
> : # pd -alsa -verbose -blocksize 1024 -r 96000 -rt
> :       pd/doc/7.stuff/tools/latency.pd
> : reading startup file: /root/.pdrc
> : Pd version 0.36-0
> : compiled 21:02:57 Feb 19 2003
> : device 1: tried /dev/midi READ/WRITE; returned 3
> : opened 1 MIDI input device(s) and 1 MIDI output device(s).
> : audio buffer set to 40 ms
> : opening sound input...
> : Using noninterleaved mode
> : snd_pcm_hw_params_set_channels (input): Invalid argument
> : ALSA lib pcm_hw.c:297:(snd_pcm_hw_hw_params) SNDRV_PCM_IOCTL_HW_PARAMS
> : failed: Device or resource busy
> : snd_pcm_hw_params (input): Device or resource busy
> : pd: pcm.c:4907: snd_pcm_sw_params_current: Assertion `pcm->setup'
> : failed.
> : Aborted
>
> Remember to do a warm-boot if you don't get any output from the
> multiface...
>
>  j#|@
>
> On Fri, 14 Feb 2003, guenter geiger wrote:
>
> >
> > Hi,
> >
> > Finally I have been able to get pd running with the Hammerfall and
> > the ALSA drivers.
> > It did cost me more time than I thought, at the end I was randomly
> > trying different combinations of hundreds of calls for setting
> > fragmentsizes, fragment numbers, samplerate and channels, ...
> > and ... one combination worked !
> >
> > Latency is not too good, I think this is because the driver currently
> > works in non-blocking mode. So be sure to set "-bufsize 256" or bigger.
> > (e.g.512,1024,2048,4096).
> >
> > The code is in CVS, checkout with
> >
> > #> cvs -d:pserver:anonymous at cvs.sourceforge.net:/cvsroot/pure-data login
> >
> > #> cvs -z3 -d:pserver:anonymous at cvs.sourceforge.net:/cvsroot/pure-data co
> > -r devel_0_36
> >
> > For those who work with the non CVS version, download s_linux.c from
> > http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/pure-data/pd/src/?only_with_tag=devel_0_36
> >
> > put it into your pd/src directory and recompile.
> >
> > I do not know how well it runs on an HDSP (please report).
> >
> > Guenter
>