prevented it from switching dma channels when using dual dma and polled, unless a...

has actually occured.

diff --git a/comedi/drivers/das1800.c b/comedi/drivers/das1800.c
index 67009a00d58efd8992dc1129579044a24e1c0061..7be8e768cb9c99bf659b4b7310978a5e1ac4c889 100644 (file)
--- a/comedi/drivers/das1800.c
+++ b/comedi/drivers/das1800.c
@@ -193,7 +193,7 @@ static int das1800_cancel(comedi_device *dev, comedi_subdevice *s);
 static void das1800_interrupt(int irq, void *d, struct pt_regs *regs);
 static int das1800_ai_poll(comedi_device *dev,comedi_subdevice *s);
 static void das1800_ai_handler(comedi_device *dev);
-static void das1800_handle_dma(comedi_device *dev, comedi_subdevice *s);
+static void das1800_handle_dma(comedi_device *dev, comedi_subdevice *s, unsigned int status);
 static void das1800_flush_dma(comedi_device *dev, comedi_subdevice *s);
 static void das1800_flush_dma_channel(comedi_device *dev, comedi_subdevice *s, unsigned int channel, u16 *buffer);
 static void das1800_handle_fifo_half_full(comedi_device *dev, comedi_subdevice *s);
@@ -926,13 +926,8 @@ static void das1800_ai_handler(comedi_device *dev)
        // dma buffer full
        if(devpriv->irq_dma_bits & DMA_ENABLED)
        {
-               if(status & DMATC)
-               {
-                       // clear DMATC interrupt bit
-                       outb(CLEAR_INTR_MASK & ~DMATC, dev->iobase + DAS1800_STATUS);
-               }
                // look for data from dma transfer even if dma terminal count hasn't happened yet
-               das1800_handle_dma(dev, s);
+               das1800_handle_dma(dev, s, status);
        }else if(status & FHF)
        {       // if fifo half full
                das1800_handle_fifo_half_full(dev, s);
@@ -978,7 +973,7 @@ static void das1800_ai_handler(comedi_device *dev)
        return;
 }
 
-static void das1800_handle_dma(comedi_device *dev, comedi_subdevice *s)
+static void das1800_handle_dma(comedi_device *dev, comedi_subdevice *s, unsigned int status)
 {
        unsigned long flags;
        const int dual_dma = devpriv->irq_dma_bits & DMA_DUAL;
@@ -991,26 +986,32 @@ static void das1800_handle_dma(comedi_device *dev, comedi_subdevice *s)
        enable_dma(devpriv->dma_current);
        release_dma_lock(flags);
 
-       if(dual_dma)
+       if(status & DMATC)
        {
-               // read data from the other channel next time
-               if(devpriv->dma_current == devpriv->dma0)
+               // clear DMATC interrupt bit
+               outb(CLEAR_INTR_MASK & ~DMATC, dev->iobase + DAS1800_STATUS);
+               // switch dma channels for next time, if appropriate
+               if(dual_dma)
                {
-                       devpriv->dma_current = devpriv->dma1;
-                       devpriv->dma_current_buf = devpriv->dma_buf1;
-               }
-               else
-               {
-                       devpriv->dma_current = devpriv->dma0;
-                       devpriv->dma_current_buf = devpriv->dma_buf0;
+                       // read data from the other channel next time
+                       if(devpriv->dma_current == devpriv->dma0)
+                       {
+                               devpriv->dma_current = devpriv->dma1;
+                               devpriv->dma_current_buf = devpriv->dma_buf1;
+                       }
+                       else
+                       {
+                               devpriv->dma_current = devpriv->dma0;
+                               devpriv->dma_current_buf = devpriv->dma_buf0;
+                       }
                }
        }
 
        return;
 }
 
-/* utility function used by das1800_flush_dma() and das1800_handle_dma()
- * assumes dma lock is held */
+/* Utility function used by das1800_flush_dma() and das1800_handle_dma().
+ * Assumes dma lock is held */
 static void das1800_flush_dma_channel(comedi_device *dev, comedi_subdevice *s, unsigned int channel, u16 *buffer)
 {
        unsigned int numPoints;