derek holzer wrote on 2/23/05:
I messed around with Gentoo on a couple of old Pismos, and I never got the sound-in working. This was with ALSA and JACK, and either I had no signal at all or a huge electronic hum. Sorry, but I'm pretty sure it has to do with that specific Pismo soundcard...
Hi Derek-
Just to clarify, I _AM_ able to get PD to produce sound if I use the -noadc option. I'll have to check to see whether I'm OK on input using the -nodac option, although I can't imagine how useful that would be. This is with a more-or-less stock Woody distro on a Mac Pismo laptop.
I looked at the source in s_audio-oss.c and what appears to be happening is that PD opens the available devices for Read/Write, programs the output channels and then the input channels. Trouble is, under OSS/dma_soundpmac driver, reprogramming the "same" channels genrates an error, which is where it chokes on my Pismo.
I've noticed this with a couple of other apps, notably Sweep and Iain Sandoe's driver test code. The Mac driver supports signed 16-bit big-endian data at 44100 and complains when it's re-programmed, or programmed again for some reason. Sweep, for example, caught the error and then exited, but commenting out the exit() calls and re-compiling seems to work fine.
I suppose that ultimately I'll move to ALSA, but being pretty new to Linux, I'd like to get a better understanding of what's going on before I jump.
Best,
Charles