Patch for cleaner analog output underrun handling from Ray Kelm

diff --git a/comedi/drivers/ni_mio_common.c b/comedi/drivers/ni_mio_common.c
index 622f57a6548045c477f5aea540abc56b868f65c1..559d4ef979299387a7083011d095ac5763f2aa92 100644 (file)
--- a/comedi/drivers/ni_mio_common.c
+++ b/comedi/drivers/ni_mio_common.c
@@ -567,6 +567,7 @@ static void handle_a_interrupt(comedi_device *dev,unsigned short status,
 
 static void handle_b_interrupt(comedi_device *dev,unsigned short b_status)
 {
+       int ret;
        comedi_subdevice *s=dev->subdevices+1;
        //unsigned short ack=0;
 
@@ -582,8 +583,16 @@ static void handle_b_interrupt(comedi_device *dev,unsigned short b_status)
                s->async->events |= COMEDI_CB_EOA;
        }
 
-       if(b_status&AO_FIFO_Request_St)
-               ni_ao_fifo_half_empty(dev,s);
+       if(b_status&AO_FIFO_Request_St){
+               ret = ni_ao_fifo_half_empty(dev,s);
+               
+               if(!ret){
+                       rt_printk("ni_mio_common: AO buffer underrun\n");
+                       ni_set_bits(dev, Interrupt_B_Enable_Register,
+                               AO_FIFO_Interrupt_Enable|AO_Error_Interrupt_Enable, 0);
+                       s->async->events |= COMEDI_CB_OVERFLOW;
+               }
+       }
 
        b_status=win_in(AO_Status_1_Register);
        if(b_status&Interrupt_B_St){