diff --git a/drivers/staging/comedi/drivers/amplc_dio200.c b/drivers/staging/comedi/drivers/amplc_dio200.c
index 17d2e20663cb..d605fd95cc50 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200.c
@@ -265,16 +265,11 @@ static const struct dio200_board dio200_isa_boards[] = {
 static int dio200_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 {
 	const struct dio200_board *thisboard = comedi_board(dev);
-	struct dio200_private *devpriv;
 	unsigned int irq;
 	int ret;
 
 	irq = it->options[1];
 
-	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
-	if (!devpriv)
-		return -ENOMEM;
-
 	ret = comedi_request_region(dev, it->options[0], thisboard->mainsize);
 	if (ret)
 		return ret;
diff --git a/drivers/staging/comedi/drivers/amplc_dio200.h b/drivers/staging/comedi/drivers/amplc_dio200.h
index e0afe2cee2d6..b21ed526a960 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200.h
+++ b/drivers/staging/comedi/drivers/amplc_dio200.h
@@ -59,13 +59,6 @@ struct dio200_board {
 	unsigned int mainsize;
 };
 
-/*
- * Comedi device private data.
- */
-struct dio200_private {
-	int intr_sd;
-};
-
 int amplc_dio200_common_attach(struct comedi_device *dev, unsigned int irq,
 			       unsigned long req_irq_flags);
 
diff --git a/drivers/staging/comedi/drivers/amplc_dio200_common.c b/drivers/staging/comedi/drivers/amplc_dio200_common.c
index f0d709e0dafc..775263c1471e 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200_common.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200_common.c
@@ -574,19 +574,13 @@ dio200_subdev_intr_init(struct comedi_device *dev, struct comedi_subdevice *s,
 static irqreturn_t dio200_interrupt(int irq, void *d)
 {
 	struct comedi_device *dev = d;
-	struct dio200_private *devpriv = dev->private;
-	struct comedi_subdevice *s;
+	struct comedi_subdevice *s = dev->read_subdev;
 	int handled;
 
 	if (!dev->attached)
 		return IRQ_NONE;
 
-	if (devpriv->intr_sd >= 0) {
-		s = &dev->subdevices[devpriv->intr_sd];
-		handled = dio200_handle_read_intr(dev, s);
-	} else {
-		handled = 0;
-	}
+	handled = dio200_handle_read_intr(dev, s);
 
 	return IRQ_RETVAL(handled);
 }
@@ -1122,15 +1116,11 @@ int amplc_dio200_common_attach(struct comedi_device *dev, unsigned int irq,
 			       unsigned long req_irq_flags)
 {
 	const struct dio200_board *thisboard = comedi_board(dev);
-	struct dio200_private *devpriv = dev->private;
 	const struct dio200_layout *layout = dio200_board_layout(thisboard);
 	struct comedi_subdevice *s;
-	int sdx;
 	unsigned int n;
 	int ret;
 
-	devpriv->intr_sd = -1;
-
 	ret = comedi_alloc_subdevices(dev, layout->n_subdevs);
 	if (ret)
 		return ret;
@@ -1154,14 +1144,14 @@ int amplc_dio200_common_attach(struct comedi_device *dev, unsigned int irq,
 			break;
 		case sd_intr:
 			/* 'INTERRUPT' subdevice */
-			if (irq) {
+			if (irq && !dev->read_subdev) {
 				ret = dio200_subdev_intr_init(dev, s,
 							      DIO200_INT_SCE,
 							      layout->sdinfo[n]
 							     );
 				if (ret < 0)
 					return ret;
-				devpriv->intr_sd = n;
+				dev->read_subdev = s;
 			} else {
 				s->type = COMEDI_SUBD_UNUSED;
 			}
@@ -1176,10 +1166,8 @@ int amplc_dio200_common_attach(struct comedi_device *dev, unsigned int irq,
 			break;
 		}
 	}
-	sdx = devpriv->intr_sd;
-	if (sdx >= 0 && sdx < dev->n_subdevices)
-		dev->read_subdev = &dev->subdevices[sdx];
-	if (irq) {
+
+	if (irq && dev->read_subdev) {
 		if (request_irq(irq, dio200_interrupt, req_irq_flags,
 				dev->board_name, dev) >= 0) {
 			dev->irq = irq;
diff --git a/drivers/staging/comedi/drivers/amplc_dio200_pci.c b/drivers/staging/comedi/drivers/amplc_dio200_pci.c
index fbf05687347f..f4170f899487 100644
--- a/drivers/staging/comedi/drivers/amplc_dio200_pci.c
+++ b/drivers/staging/comedi/drivers/amplc_dio200_pci.c
@@ -359,7 +359,6 @@ static int dio200_pci_auto_attach(struct comedi_device *dev,
 {
 	struct pci_dev *pci_dev = comedi_to_pci_dev(dev);
 	const struct dio200_board *thisboard = NULL;
-	struct dio200_private *devpriv;
 	unsigned int bar;
 	int ret;
 
@@ -373,10 +372,6 @@ static int dio200_pci_auto_attach(struct comedi_device *dev,
 	dev_info(dev->class_dev, "%s: attach pci %s (%s)\n",
 		 dev->driver->driver_name, pci_name(pci_dev), dev->board_name);
 
-	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
-	if (!devpriv)
-		return -ENOMEM;
-
 	ret = comedi_pci_enable(dev);
 	if (ret)
 		return ret;