[nas] [PATCH] changed method of setting the input gain

[Paul Fox]

erik wrote:
 > > I'd say it does not need to be configurable. I've just checked the OSS
 > > programming manual and it's official that several programms can open the
 > > mixer device at the same time. And I agree that a seperate boolean
 > > should be used if it should be configurable nevertheless.
 > 
 > There was already a variable to control this (but no code did use it).
 > The attached patch implements this config variable for the voxware
 > server.

documentation thought:  i think we need to start stating, in both
the man page and in the config file comments, what the default
behavior is for each of our booleans.  there's a tendency to edit
the originally-installed file to make changes, and then any
indication of the server default is lost.

 > 
 > > >         If this can be done (track mixer changes), and mixer usage is
 > > >         configured to be allowed, then it should 'just work', no
 > > >         option neccessary.  IMO of course.
 > > 
 > > That can be done. In the getPhysical* functions the mixer can be
 > > queried. We would not need the last* variables any more (I think). I've
 > > already tested this for the output gain and can come up with a patch.
 > > I'll wait for the re-indentation patch first. ;-)
 > 
 > The patch is attached to this mail. It is not without issues, though:

one change:  when reading the gain, you have to do inverse gain scaling:

--- server/dda/voxware/auvoxware.c.erik	Thu Jul 27 08:18:38 2006
+++ server/dda/voxware/auvoxware.c	Thu Jul 27 08:21:29 2006
@@ -361,6 +361,11 @@
                      sndStatOut.mixer, mixerfd, strerror(errno));
         }
         pcm_level = pcm_level >> 8;
+        if (sndStatOut.gainScale ) {
+	    pcm_level *= 100;
+	    pcm_level /= sndStatOut.gainScale;
+	    if (pcm_level > 100) pcm_level = 100;
+	}
     } else {
         pcm_level = sndStatOut.gain;
     }

the tracking seems to work for me, after applying this.  thanks!

another question though:  i haven't tried it, but since you've
eliminated the last* variables, if the mixer is closed, you
always report the default sndStatOut.mixer.  but if the user sets
keepmixer to false, doesn't this mean that no nas-based mixer can
report a true value?  i'm confused.  (in fact, i did just try
setting keepmixer to "no", and sure enough, my "audiooss aumix"
is now locked at 50%.  oh.  wait.  i didn't have a stream
playing.  if i play a stream, then the nas mixer works correctly. 
is the total lockout when the pcm device isn't open the expected
behavior?  i thought it would work like it did before.

 > When reading the IGain value from the mixer the ioctl returns -1 with
 > errno == 0 (success) most of the time. The value was read correctly
 > every time I tested this regardless of error reported. I have no idea
 > why this happens. The patch works for me, it justs spams the logfiles
 > with lots of error: success messages. I was using aupanel to control the
 > NAS mixer, I did not check if auctl behaves the same (it should).

my logs look like this.  i got one "success" message, but a bunch of
EINTR. calls.  not sure what those are from.

Jul 27 08:22:53 localhost nas[22959]: Network Audio System Release 1.8 
Jul 27 08:22:53 localhost nas[22960]: Init: Input open(/dev/dsp1) failed: No such device, using output device 
Jul 27 08:23:05 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: No such device 
Jul 27 08:23:05 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: No such file or directory 
Jul 27 08:23:05 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: No such file or directory 
Jul 27 08:23:13 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: Interrupted system call 
Jul 27 08:23:15 localhost last message repeated 4 times
Jul 27 08:23:16 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: Success 
Jul 27 08:23:16 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: Interrupted system call 
Jul 27 08:23:43 localhost last message repeated 16 times
Jul 27 08:24:38 localhost last message repeated 9 times
Jul 27 08:26:18 localhost nas[22960]: readMixerInputGain: /dev/mixer: ioctl(MIXER_READ(SOUND_MIXER_IGAIN)) failed: No such file or directory 


paul
=---------------------
 paul fox, pgf at foxharp.boston.ma.us (arlington, ma, where it's 70.3 degrees)