mmap is supported by the Samsung drivers.
Thanks for this information which i overlooked.
This looks like the dmix data rates are getting out of sync with what the hardware is doing. Enabling CONFIG_SND_PCM_XRUN_DEBUG will produce more diagnostic information from the driver side
I got the problem and after doing the changes DMIX plugin is working very fine. As you know XRUN was happening and this happening in snd_pcm_update_hw_ptr_post function. This happened because stop_threshold is increased suddenly(Is it done by dmix? If yes then why ?) ?????? In normal condtions this would have been fine but in my code i was multiplying it by some amount causing it to wrap around(stop_threshold=0 );Causing XRUN.So i just removed this multiplying factor.
One more Rate conversion query: ./alsa_aplay -v -D"plug:'dmix:RATE=44100'" bond.wav Playing WAVE 'bond.wav' : Unsigned 8 bit, Rate 11025 Hz, Mono Plug PCM: Rate conversion PCM (44100, sformat=U8) As you can see bond.wav is sampled at 11025k 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?
If i play with ./alsa_aplay -v -D"plug:'dmix:RATE=11025'" bond.wav then no noise.Probably because no resampling happening?
Mark Brown Heartfelt Thanks for your time.