diff --git a/drivers/staging/comedi/drivers/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c
index ad1f347066435b96cc472e24202a5eb9e022efd0..fb9141274e19a0e0a32a6a4f6c20bc2e4f2de5c3 100644
--- a/drivers/staging/comedi/drivers/pcl818.c
+++ b/drivers/staging/comedi/drivers/pcl818.c
@@ -290,7 +290,6 @@ struct pcl818_private {
 	unsigned int ai_data_len;	/*  len of data buffer */
 	unsigned int ai_timer1;	/*  timers */
 	unsigned int ai_timer2;
-	struct comedi_subdevice *sub_ai;	/*  ptr to AI subdevice */
 	unsigned char usefifo;	/*  1=use fifo */
 	unsigned int ao_readback[2];
 };
@@ -1269,7 +1268,6 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 		s->type = COMEDI_SUBD_UNUSED;
 	} else {
 		s->type = COMEDI_SUBD_AI;
-		devpriv->sub_ai = s;
 		s->subdev_flags = SDF_READABLE;
 		if (check_single_ended(dev->iobase)) {
 			s->n_chan = board->n_aichan_se;
@@ -1403,7 +1401,7 @@ static void pcl818_detach(struct comedi_device *dev)
 	struct pcl818_private *devpriv = dev->private;
 
 	if (devpriv) {
-		pcl818_ai_cancel(dev, devpriv->sub_ai);
+		pcl818_ai_cancel(dev, dev->read_subdev);
 		pcl818_reset(dev);
 		if (devpriv->dma)
 			free_dma(devpriv->dma);