make underrun detection play nice with stop_src TRIG_COUNT

diff --git a/comedi/drivers/ni_mio_common.c b/comedi/drivers/ni_mio_common.c
index 167c70420d36956021f15ed674626362fa7aba0f..a61bb6ed400e72a2b2966d217455e561dc44035a 100644 (file)
--- a/comedi/drivers/ni_mio_common.c
+++ b/comedi/drivers/ni_mio_common.c
@@ -367,6 +367,9 @@ static void mite_handle_b_linkc(struct mite_struct *mite, comedi_device *dev)
        new_write_count = async->buf_write_count;
 
        nbytes = mite_bytes_read(mite, AO_DMA_CHAN);
+       if( async->cmd.stop_src == TRIG_COUNT &&
+               (int) (nbytes - async->cmd.stop_arg * sizeof( sampl_t ) ) > 0 )
+               nbytes = async->cmd.stop_arg * sizeof( sampl_t );
        if( (int)(nbytes - devpriv->last_buf_write_count) > 0 ){
                rt_printk("ni_mio_common: DMA underrun\n");
                ni_ao_reset(dev,s);