hdsp vs 16bit vs dmix

[Patrick Shirkey <pshirkey@boosthardware.com>]

I am seeing strange things happen while using the hdsp and dmix plugin 
and aplay as a test app.

JACK works perfectly.

I can get sound from aplay if I use this commandline:

aplay -f cd -D plughw audio.wav
Playing WAVE 'audio.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, 
Stereo
underrun!!! (at least 40.147 ms long)
underrun!!! (at least 86.223 ms long)
underrun!!! (at least 145.116 ms long)
underrun!!! (at least 79.109 ms long)
underrun!!! (at least 248.555 ms long)
underrun!!! (at least 180.442 ms long)
underrun!!! (at least 96.117 ms long)
Aborted by signal Interrupt...	

But I get an xrun every second or so which makes the card useless for 
native alsa apps .

aplay -f cd -D hw:0 audio.wav
Playing WAVE 'audio.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, 
Stereo
aplay: set_params:822: Access type not available


If I try the dmix plugin (which also works with the pci card):


  pcm.!default {
            type plug
            slave.pcm "dmixer"
         }

pcm.dmixer  {
     type dmix
     ipc_key 1234
     slave {
         pcm "hw:0"
         period_time 0
         period_size 1024
         buffer_size 4096
#        periods 128
         rate 44100
         format s16_le
     }
     bindings {
         0 0
         1 1
     }
}

ctl.dmixer {
     type hw
     card 0
}

------
  aplay -f cd -D default audio.wav
ALSA lib pcm_hw.c:324:(snd_pcm_hw_hw_params) SNDRV_PCM_IOCTL_HW_PARAMS 
failed: Device or resource busy
ALSA lib pcm_direct.c:712:(snd_pcm_direct_initialize_slave) unable to 
install hw params
ALSA lib pcm_dmix.c:827:(snd_pcm_dmix_open) unable to initialize slave
aplay: main:502: audio open error: Device or resource busy
------

For fun I tried this syntax:


  pcm.!default {
            type plughw
            slave.pcm "dmixer"
         }


------
  aplay -f cd -D default audio.wav
ALSA lib pcm.c:1900:(snd_pcm_open_conf) Cannot open shared library 
/usr/lib/alsa-lib/libasound_module_pcm_plughw.so
aplay: main:502: audio open error: No such file or directory
------


-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://www.djcj.org - The Linux Audio Users guide
========================================


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