diff --git a/drivers/comedi/drivers/comedi_parport.c b/drivers/comedi/drivers/comedi_parport.c
index 2604680d86c4..57ee3f9dfba2 100644
--- a/drivers/comedi/drivers/comedi_parport.c
+++ b/drivers/comedi/drivers/comedi_parport.c
@@ -211,6 +211,13 @@ static irqreturn_t parport_interrupt(int irq, void *d)
 	unsigned int ctrl;
 	unsigned short val = 0;
 
+	/*
+	 * Check device is fully attached.  Device interrupts should have
+	 * been disabled, but do this in case of bad hardware.
+	 */
+	if (!dev->attached)
+		return IRQ_NONE;
+
 	ctrl = inb(dev->iobase + PARPORT_CTRL_REG);
 	if (!(ctrl & PARPORT_CTRL_IRQ_ENA))
 		return IRQ_NONE;
@@ -233,6 +240,9 @@ static int parport_attach(struct comedi_device *dev,
 	if (ret)
 		return ret;
 
+	outb(0, dev->iobase + PARPORT_DATA_REG);
+	outb(0, dev->iobase + PARPORT_CTRL_REG);
+
 	if (it->options[1]) {
 		ret = request_irq(it->options[1], parport_interrupt, 0,
 				  dev->board_name, dev);
@@ -288,9 +298,6 @@ static int parport_attach(struct comedi_device *dev,
 		s->cancel	= parport_intr_cancel;
 	}
 
-	outb(0, dev->iobase + PARPORT_DATA_REG);
-	outb(0, dev->iobase + PARPORT_CTRL_REG);
-
 	return 0;
 }