For dmix, the stop_threshold should be equal to boundary value, thus XRUN check should never be true. If you got xrun with dmix, something is wrong.

DMIX is working now.

but when i am playing with Plug PCM there is some noise in the song why????Is rate conversion algoritm not able to resample it properly? The default linear resampler is not very good quality. You may use some sox resamplers from the alsa-plugins package, but they're more CPU intensive. Check google.

Actually i am working on soc platform(android-S3C6410) and wanted to use DMIX and some good resampler for my software mixing instead of current software mixing and resampling in upper layer(Above alsa-lib).DMIX is working fine but this resampling is causing some jitter.During rate conversion it looks for libasound_module_rate_speexrate.so which i don't have so its using default one causing the jitter. Can i build this .so file (as current way of alsa-plugin downloading will not work for me)?For sox resampler i guess i need to use differnet .so and corresponding changes in asound.conf file?? Can i get speex or sox resampler code so that i can build it for my system????? This code(speex or sox) i guess would have been integrated with alsa-lib so that alsa-lib can call corresponding functions of resampler source code.

OR simply point me to url as googling is not helping.Everywhere i am getting this "you need to download plugins".This will not work in my case.