[alsa-devel] ask about audio latency

hi

I want to get the latency between record and playback, so i use following solution to calculate it.

#audio.sh arecord -d 3 -r 96000 in.wav & sleep 1 aplay mode.wav

model.wav is a sine wave. this file is used for calculate the delta timestamp of record and playback. I have append do_gettimeofday() function in azx_stream_start() in hda_intel.c file. it will printk the dma trigger time after trigger dma.

the result is about 12ms. as far as i known. fifo size is 192, sample rate is 96000, so it will take about 2ms latency, my question is where does the other 10ms latency come from?

Thanks