recently,i am tracing the process into the snd_pcm_update_hw_ptr0() and find the statement. i do not understand when the

if (hdelta > runtime->hw_ptr_buffer_jiffies/2) (1)will happen? (2)and the reason? (3)the other question is if the dma interrupt will can enter the snd_pcm_update_hw_ptr0() every time when it ocurrs?

thanks for any suggestion. Best Regards L9jj

=====================code start==============================> if (in_interrupt) { /* we know that one period was processed */

/* delta = "expected next hw_ptr" for in_interrupt != 0 */

delta = runtime->hw_ptr_interrupt + runtime->period_size;

if (delta > new_hw_ptr) {

/* check for double acknowledged interrupts */

hdelta = jiffies - runtime->hw_ptr_jiffies;

if (hdelta > runtime->hw_ptr_buffer_jiffies/2) {

hw_base += runtime->buffer_size;

if (hw_base >= runtime->boundary)

hw_base = 0;

new_hw_ptr = hw_base + pos;

goto __delta;

}

}

<=====================code end============================

-- ------------------------------------ l9jj Regards