On Fri, Jul 04, 2003 at 02:12:49AM -0700, Joseph Lunderville wrote: > I'm trying to get a 486 with a GUS Classic working through ALSA, and I've > run into a couple of problems: > > > 1. plughw doesn't know how to convert from interleaved data to > noninterleaved data. in fact, as far as I can see, nothing at all except the > GUS driver knows what to do with noninterleaved data.
I ran into this problem with my GUS PnP some time ago. You should be able to find the discussion from alsa-devel archives. Apparently the conversion works for some other non-interleaved cards like RME Hammerfall. The GUS driver doesn't support mmap which may cause problems but even using alsa-lib's mmap emulation didn't fix the problem for me :( > I imagine that the only > reason this hasn't been fixed yet is that nobody wants to use a GUS with > ALSA :) I will resurrect my GUS PnP when (if?) MIDI emulation gets implemented... > 2. the GUS driver seems to have a problem with outputting PCM data. I had to > test it using my own code (since the example uses interleaved data), but I'm > reasonably confident that the problem's in the driver. > > the problem I'm observing is that there are frequent clicks in the audio > output (coincidentally, they arrive at a frequency corresponding exactly to > the size of the ring buffer -- I've confirmed this by looking at the output > on an oscilloscope. the click looks like one or two samples are being > skipped). this is when I use a buffer size that's a multiple of my period > size -- when I use other combinations of buffer size and period size, things > get worse. some combinations of buffer & period size cause I/O errors. > > 3. finally, the example doesn't start the audio output. it's difficult for > me to tell whether you're supposed to call snd_pcm_start() in order to get > output from the speakers (in which case the example is wrong), or whether > the gus driver requires this when it's not supposed to, but either way > something's not right. I don't remember seeing this with my GUS PnP but then again I mostly used the codec instead of the synth for PCM. Also GUS PnP doesn't have the channel count vs. frequency limitation of the original GUS. I have a GUS MAX buried somewhere but I don't think I've tried it with ALSA. -- Ville Syrjälä [EMAIL PROTECTED] http://www.sci.fi/~syrjala/ ------------------------------------------------------- This SF.Net email sponsored by: Parasoft Error proof Web apps, automate testing & more. Download & eval WebKing and get a free book. www.parasoft.com/bulletproofapps _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
