[PD] HDSP - ALSA - OSS - PD - Confusion

[Iain Mott]

Hello

after a good deal of pain and discomfort I have a HDSP/Multiface unit 
running with ALSA (the latest CVS) and to my amazement just now, with Pd.

The only version of Pd that seems to work with my setup is this CVS 
version (0.37 TEST 4) - (incidentally, fiddle~ seems to be broken in this 
release). I configured the compilation using the --enable-alsa flag, 
however I'm not certain it's actually using ALSA. When Pd starts in 
verbose mode I get the following print out:


[iain at mother src]$ /home/iain/projects/puredata/pd/bin/pd -mididev 1  
-verbose -channels 18
Pd version 0.37 TEST 4
compiled 16:15:21 Jul 22 2003
device 1: tried /dev/midi READ/WRITE; returned 3
opened 1 MIDI input device(s) and 1 MIDI output device(s).
input channels = 18, output channels = 18
opened /dev/dsp for reading and writing
 
opened audio output on /dev/dsp; got 18 channels
bytes per sample = 2
warning: OSS takes only power of 2 blocksize; using 227
setting nfrags = 8, fragsize 9216
 
audiobuffer set to 50 msec
OSS: requested audio buffer size 79380 limited to 18432
opened audio input device /dev/dsp; got 18 channels
bytes per sample = 2
OSS: issuing first ADC 'read' ... ...done.
port 5400
Waiting for connection request...
TCL_LIBRARY="/home/iain/projects/puredata/pd/tcl/library" 
TK_LIBRARY="/home/iain/projects/puredata/pd/tk/library"  
"/home/iain/projects/puredata/pd/bin/pd-gui" 5400
... connected

Does the above mean Pd is using "OSS emulation" and not ALSA proper? I'm 
pretty confused about the whole thing - hope someone can clarify what's 
going on. I notice the -alsa flag seems to be gone from this version of 
Pd - don't know if that has anything to do with it. Also, the setup seems 
to be limited to buffer sizes of 15msec and higher - any less and 
dropouts occur. How can I improve this? I'm currently running a Vanilla 
2.4.20 kernel - will I need low latency patches etc?

Cheers,

Iain

_____
Iain Mott
www.reverberant.com