#endif /*  PCIDMA */
 }
 
-/* e-series boards use the second irq signals to generate dma requests for their counters */
 #ifdef PCIDMA
 static void ni_e_series_enable_second_irq(struct comedi_device *dev,
                                          unsigned gpct_index, short enable)
 {
        struct ni_private *devpriv = dev->private;
+       uint16_t val = 0;
+       int reg;
 
-       if (devpriv->is_m_series)
+       if (devpriv->is_m_series || gpct_index > 1)
                return;
-       switch (gpct_index) {
-       case 0:
-               if (enable) {
-                       devpriv->stc_writew(dev, G0_Gate_Second_Irq_Enable,
-                                           Second_IRQ_A_Enable_Register);
-               } else {
-                       devpriv->stc_writew(dev, 0,
-                                           Second_IRQ_A_Enable_Register);
-               }
-               break;
-       case 1:
-               if (enable) {
-                       devpriv->stc_writew(dev, G1_Gate_Second_Irq_Enable,
-                                           Second_IRQ_B_Enable_Register);
-               } else {
-                       devpriv->stc_writew(dev, 0,
-                                           Second_IRQ_B_Enable_Register);
-               }
-               break;
-       default:
-               BUG();
-               break;
+
+       /*
+        * e-series boards use the second irq signals to generate
+        * dma requests for their counters
+        */
+       if (gpct_index == 0) {
+               reg = Second_IRQ_A_Enable_Register;
+               if (enable)
+                       val = G0_Gate_Second_Irq_Enable;
+       } else {
+               reg = Second_IRQ_B_Enable_Register;
+               if (enable)
+                       val = G1_Gate_Second_Irq_Enable;
        }
+       devpriv->stc_writew(dev, val, reg);
 }
 #endif /*  PCIDMA */