[nas] isolate input/output?

[Paul Fox]

hi -- i've had a chance to try this, and now i'm confused.  :-)
i'm running release 1.8a of nasd.

as a reminder, i'm trying to configure an output-only nasd.  a
different application will be opening the input side of the device.

erik wrote:
 > On Fri, Mar 09, 2007 at 07:15:20PM -0500, Paul Fox wrote:
 > > i need to be able to tell nasd to use its normal output channels,
 > > for remote access, but to leave the mic input alone, so that it
 > > can be used by a local app.  can i do this currently?  or are the
 > > inputs and outputs all tied together in the single mixer device?
 > 
 > The input device is only opened if there is some NAS client requesting
 > data from it (if ReleaseDevice is set to "yes" in the config file). This
 > is independant of the input mixer settings. If MixerInit is set to "no",
 > then the mixer settings will not be changed when nasd is started.

this all works correctly, i believe.

 > 
 > Since version 1.8a the input- and output-devices can be totally
 > independant, including the mixer (for the OSS NAS server).
 > 
 > You can set the mixer in the inputsection of the config file to the
 > empty string ("") to disable any input gain control for NAS. The mixer
 > settings will not be changed by nasd in this case.
 > 
 > If you set autoOpen to "no" in the input section, nasd will not even try
 > to open an input device, unless some NAS client tries to read from the
 > input device.

first, a typo bug in openDevice(), in auvoxware.c.  however, in practice,
i don't think we ever execute this code.  (i found this by inspection --
i can't make it fail.)

--- /tmp/nas-1.8a/server/dda/voxware/auvoxware.c	Wed Aug 30 20:46:11 2006
+++ dda/voxware/auvoxware.c	Sat Mar 10 20:33:27 2007
@@ -873,7 +873,7 @@
     }
 
     if ((inmixerfd == -1) && !share_mixer) {
-        if (sndStatIn.mixer[0] != '\0') {
+        if (sndStatIn.mixer[0] == '\0') {
             osLogMsg("openDevice: no input mixer device specified\n");
         } else {
             while ((inmixerfd = open(sndStatIn.mixer, O_RDWR | extramode,


but to get things to work, in addition to the things you said
above, i also have to set the input device to /dev/null, and it's
kind of complicate as to why.  setting it to either a nonexistent
device (/dev/dsp1) or to the same device as output (/dev/dsp)
causes nasd to loop 5 times, with timeout, when trying to open
the input device.  in the former case it's because the device
doesn't exist, and in the latter, i think it's because the device
is already open (for output).  

note that this looping i'm referring to all happens at client
connection time, since i have autoOpen disabled.  things work
better with autoOpen enabled, since in that case, failure to open
the input device initially causes the "share_in_out" flag to be
set, which suppresses later opens of the input device.

paul
=---------------------
 paul fox, pgf at foxharp.boston.ma.us (arlington, ma, where it's 41.7 degrees)