trying to make sure the interrupt handler doesn't have any races with the hardware

diff --git a/comedi/drivers/cb_pcidas.c b/comedi/drivers/cb_pcidas.c
index 7a41d7ec7d939bffd61dbc84615192526bea144f..3b55ea9b19299471af61abe5055bdb9572fdabde 100644 (file)
--- a/comedi/drivers/cb_pcidas.c
+++ b/comedi/drivers/cb_pcidas.c
@@ -1023,6 +1023,8 @@ static int cb_pcidas_ai_cmd(comedi_device *dev,comedi_subdevice *s)
        outw(devpriv->adc_fifo_bits | EOAI | INT | LADFUL, devpriv->control_status + INT_ADCFIFO);
        // enable s5933 interrupt
        outl(devpriv->s5933_intcsr_bits, devpriv->s5933_config + INTCSR);
+       // make sure mailbox 3 is empty
+       inl(devpriv->s5933_config + INCOMING_MAILBOX(3));
 
 
        // set start trigger and burst mode
@@ -1259,6 +1261,8 @@ static int cb_pcidas_ao_inttrig(comedi_device *dev, comedi_subdevice *s, unsigne
        outw(devpriv->adc_fifo_bits | DAEMI | DAHFI, devpriv->control_status + INT_ADCFIFO);
        // enable s5933 interrupt
        outl(devpriv->s5933_intcsr_bits, devpriv->s5933_config + INTCSR);
+       // make sure mailbox 3 is empty
+       inl(devpriv->s5933_config + INCOMING_MAILBOX(3));
 
        // start dac
        devpriv->ao_control_bits |= DAC_START | DACEN | DAC_EMPTY;
@@ -1303,10 +1307,10 @@ static void cb_pcidas_interrupt(int irq, void *d, struct pt_regs *regs)
 
        if(INTR_ASSERTED & s5933_status)
        {
-               // make sure mailbox 3 is empty
-               inl(devpriv->s5933_config + INCOMING_MAILBOX(3));
                // clear interrupt on amcc s5933
                outl(devpriv->s5933_intcsr_bits | INBOX_INTR_STATUS, devpriv->s5933_config + INTCSR);
+               // make sure mailbox 3 is empty
+               inl(devpriv->s5933_config + INCOMING_MAILBOX(3));
        }
 
        status = inw(devpriv->control_status + INT_ADCFIFO);
@@ -1327,6 +1331,8 @@ static void cb_pcidas_interrupt(int irq, void *d, struct pt_regs *regs)
        // if fifo half-full
        if(status & ADHFI)
        {
+               // clear half-full interrupt latch
+               outw(devpriv->adc_fifo_bits | INT, devpriv->control_status + INT_ADCFIFO);
                // read data
                insw(devpriv->adc_fifo + ADCDATA, data, half_fifo);
                for(i = 0; i < half_fifo; i++)
@@ -1343,11 +1349,11 @@ static void cb_pcidas_interrupt(int irq, void *d, struct pt_regs *regs)
                        }
                }
                async->events |= COMEDI_CB_BLOCK;
-               // clear half-full interrupt latch
-               outw(devpriv->adc_fifo_bits | INT, devpriv->control_status + INT_ADCFIFO);
        // else if fifo not empty
        }else if(status & (ADNEI | EOBI))
        {
+               // clear not-empty interrupt latch
+               outw(devpriv->adc_fifo_bits | INT, devpriv->control_status + INT_ADCFIFO);
                for(i = 0; i < timeout; i++)
                {
                        // break if fifo is empty
@@ -1364,8 +1370,6 @@ static void cb_pcidas_interrupt(int irq, void *d, struct pt_regs *regs)
                        }
                }
                async->events |= COMEDI_CB_BLOCK;
-               // clear not-empty interrupt latch
-               outw(devpriv->adc_fifo_bits | INT, devpriv->control_status + INT_ADCFIFO);
        }else if(status & EOAI)
        {
                comedi_error(dev, "bug! encountered end of aquisition interrupt?");