[linux-audio-user] future .asoundrc example - aoss xmms setup & problems

[markknecht at comcast.net (Mark Knecht)]

Clemens,
   Hi. I made the required change to .asoundrc to map OSS to playback 5
& 6. 


pcm_slave.hdsp {
          pcm "hw:0"
          channels 26
        }

pcm.playback_5_6 {
          type dshare
          slave hdsp
          ipc_key 314159265    # some unique number
          ipc_key_add_uid yes  # "no" to let multiple users share it
          bindings {
                0 5
                1 6
          }
        }

pcm.dsp0 {
          type plug
          slave.pcm playback_5_6
        }

The results were not positive. xmms starts, but as soon as hit the play
button it exits with the following message:

bash-2.05b$ aoss xmms
xmms: alsa-oss.c:222: oss_dsp_hw_params: Assertion `err >= 0' failed.
/usr/bin/aoss: line 9: 10892 Aborted                
LD_PRELOAD=${exec_prefix}/lib/libaoss.so $*
bash-2.05b$ 

For kicks I tried mapping it to channels 0 & 1 instead, but got the same
results.

bash-2.05b$ aoss xmms
xmms: alsa-oss.c:222: oss_dsp_hw_params: Assertion `err >= 0' failed.
/usr/bin/aoss: line 9: 11022 Aborted                
LD_PRELOAD=${exec_prefix}/lib/libaoss.so $*

I checked that libaoss from yesterday's Alsa-1.0.0rc1 release and it
seems to be:

bash-2.05b$ slocate libaoss.so
/usr/lib/libaoss.so.0
/usr/lib/libaoss.so
/usr/lib/libaoss.so.0.0.0
bash-2.05b$ ls -al /usr/lib/libaoss.so*
lrwxrwxrwx    1 root     root           16 Dec  1 12:19
/usr/lib/libaoss.so -> libaoss.so.0.0.0
lrwxrwxrwx    1 root     root           16 Dec  1 12:19
/usr/lib/libaoss.so.0 -> libaoss.so.0.0.0
-rwxr-xr-x    1 root     root        43606 Dec  1 12:19
/usr/lib/libaoss.so.0.0.0
bash-2.05b$ 

However, what is interesting is that my 'wrong' example before will
actually work in aoss, except it maps xmms OSS audio to playback
channels 1 & 2. This is correct, in the sense that I get only 2 playback
channels, but they are mapped incorrectly.

<WRONG, BUT WORKS SORT OF>

pcm.dsp0 {
          type plug
          slave pcm.playback_5_6
        }

I'm confused by this. Is this an aoss problem? Is it a driver problem
WRT my HDSP 965 specifically2? Something else?

BTW - These results are vaguely familiar. I think this happened before,
and I stumbled on this 'working' option just by my trying to understand
the language and doing a bit of guessing. What I don't understand is
*why* this option that uses the language incorrectly is even allowed to
run instead of producing some message about bad parsing of .asoundrc.
Comments?

For further kicks, and it likely makes no sense at all, but I decided to
try the 'right' format in .asoundrc, but use plughw:0 instead of hw:0.
That produced an interesting message from xmms:

pcm_slave.hdsp {
          pcm "plughw:0"
          channels 26
        }


bash-2.05b$ aoss xmms

Segmentation fault

You've probably found a bug in XMMS, please visit
http://bugs.xmms.org and fill out a bug report.

Xlib: unexpected async reply (sequence 0x6d8)!



Thanks in advance for all your help.

Cheers,
Mark