[nas] native alsa bottom-end

Jon Trulson jon at radscan.com
Fri May 12 18:10:06 MDT 2006

On Fri, 12 May 2006, Paul Fox wrote:

> has anyone ever looked into writing a native alsa dda layer
> for nasd?
> mostly the oss compatibility stuff in alsa makes this
> unnecessary, but currently i'm having a very odd problem where i
> can play sounds via nasd just fine, but can't control the volume.
> i swear it used to work -- perhaps it broke in some apt-get that
> i did.  i dunno.  (this is on a debian "testing" system.)
> if i run aumix (an oss mixer) and alsamixer at the same time,
> each affects the other.  but if i run a remote mixer, nasd gets
> the messages, and perhaps does something with them, but they
> seem to have no effect.

         I am not sure what you mean by a remote mixer... I use xmms
         alot and the alsamixergui app.  I notice that when I adjust
         the volume in xmms, the PCM volume in alsamixer is adjusted,
         as it should be.

         Though note, some of the alsa drivers appears to be fairly
         crappy.  I used the intel_hda driver on my new box for a few
         days before I could no longer stand it's noisy, crappy output.
         I stuck an old SB 128 in the box, and have not looked back :)
         I am using oss emulation with alsa on this setup.

> anyway, i find myself wishing that an entire layer of complexity
> (i.e., alsa's oss emulation) would sort of go away right about
> now.  :-)


> given the size of the existing hp/sgi/sun/oss modules, it doesn't
> seem like an alsalib-based module should be difficult.  in

         I am not familiar with the alsa interface, but I image a
         'basic' stereo driver would not be too difficult (he says
         after his 3rd beer :).  But if someone wanted to do a full
         alsa driver, that could be more complicated as alsa supports
         multiple output devices, input devices, 5.1 sound, etc.  It
         would be nice to have these features supported as well someday

         I suspect that would involve somewhat more work :)

> a first scan, though, i didn't see any doc that documents the api
> at that layer.  does such a doc exist?

         Alas no... When I worked on the HP driver, I used the others
         as a template.

Jon Trulson    mailto:jon at radscan.com
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